WO2019171553A1 - Pneu - Google Patents

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Publication number
WO2019171553A1
WO2019171553A1 PCT/JP2018/009070 JP2018009070W WO2019171553A1 WO 2019171553 A1 WO2019171553 A1 WO 2019171553A1 JP 2018009070 W JP2018009070 W JP 2018009070W WO 2019171553 A1 WO2019171553 A1 WO 2019171553A1
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WO
WIPO (PCT)
Prior art keywords
tire
groove
pneumatic tire
central
width
Prior art date
Application number
PCT/JP2018/009070
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English (en)
Japanese (ja)
Inventor
孝志 芝井
Original Assignee
横浜ゴム株式会社
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
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Application filed by 横浜ゴム株式会社 filed Critical 横浜ゴム株式会社
Priority to JP2019536320A priority Critical patent/JP6729808B2/ja
Priority to PCT/JP2018/009070 priority patent/WO2019171553A1/fr
Publication of WO2019171553A1 publication Critical patent/WO2019171553A1/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
    • 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

Definitions

  • the present invention relates to a pneumatic tire, and more particularly to a pneumatic tire that can suppress the center uneven wear of the tread portion and improve the linearity of steering stability.
  • a pneumatic tire is generally disposed in a tire tread portion extending in the tire circumferential direction, a pair of sidewall portions disposed on both sides of the tread portion, and on the inner side in the tire radial direction of the sidewall portions.
  • An object of the present invention is to provide a pneumatic tire capable of suppressing the center uneven wear of the tread portion and improving the linearity of steering stability.
  • a pneumatic tire according to the present invention includes a tread portion that extends in the tire circumferential direction to form an annular shape, a pair of sidewall portions disposed on both sides of the tread portion, and the sidewall portions.
  • a pneumatic tire provided with a pair of bead portions arranged on the inner side in the tire radial direction of Loads corresponding to 40%, 75%, and 100% of the maximum load capacity defined in the standard are W40, W75, and W100 (kN), respectively, and the pneumatic tire is filled with an air pressure of 230 kPa, and the load W40,
  • the cornering powers measured under the conditions of loading W75 and W100 are CP40, CP75 and CP100 (kN / °), respectively, the flatness ratio of the pneumatic tire is R, and the outer diameter is D (mm).
  • the loads W40, W75, W100 and the cornering power CP40, CP75, CP100 are 0.05 ⁇ (R ⁇ D / 2A) 2 ⁇ [(CP100 ⁇ CP75) / (W100 ⁇ W75)] / [(CP75 ⁇ CP40) / (W75 ⁇ W40)] ⁇ 0.50 is satisfied,
  • the pneumatic tire is filled with air pressure of 230 kPa, and the maximum contact width in the tire width direction when grounded under the condition of applying the load W75 is WB1, and the tread portion is the maximum contact width WB1 centering on the tire equator.
  • the groove area Sc of the central area and the grooves of the outer area satisfies the relationship of 0.80 ⁇ Sc / Ss ⁇ 0.98.
  • the groove area Sc of the central region and the groove area Ss of the outer region satisfy the relationship of 0.80 ⁇ Sc / Ss ⁇ 0.98, and the groove area Sc in the central region is reduced, thereby reducing the tread. It is possible to secure the rigidity in the central region of the portion and suppress the center uneven wear. Further, by reducing the groove area Sc in the central region and increasing the rigidity in the central region of the tread portion, it is possible to ensure high cornering power from the low load region.
  • the loads W40, W75, W100 and the cornering powers CP40, CP75, CP100 are 0.05 ⁇ (R ⁇ D / 2A) 2 ⁇ [(CP100 ⁇ CP75) / (W100 ⁇ W75)] / [(CP75 ⁇ CP40) /(W75 ⁇ W40)] ⁇ 0.50 is satisfied, it is possible to suppress an excessive increase in cornering power in the high load region. As a result, the tire moves without delay from the initial steering of the steering wheel, and an appropriate cornering power is exhibited as the load increases, so that the linearity of steering stability can be improved.
  • a central main groove extending in the tire circumferential direction, an outer main groove extending in the tire circumferential direction at a position outside the central main groove in the tire width direction, and a tire width direction from the outer main groove A tread pattern in which a plurality of central lateral grooves extending in the tire width direction at the inner position is formed can be employed.
  • the following structure in order to secure rigidity in the center region of the tread portion, to suppress uneven wear in the center of the tread portion, and to secure high cornering power from a low load region, the following structure may be employed. That is, it is preferable that the inclination angle ⁇ cl formed by the side wall of the central lateral groove with respect to the normal line of the tread surface satisfies the relationship of 0 ° ⁇ ⁇ cl ⁇ 10 °.
  • the groove depth Dcl of the central lateral groove preferably satisfies the relationship of 0.20 ⁇ Dcl / GDc ⁇ 0.90 with respect to the groove depth GDc of the central main groove.
  • the central lateral groove has a bottom raised portion in a part of the longitudinal direction, and the groove depth Da at the bottom raised portion has a relationship of 0.20 ⁇ Da / Dcl ⁇ 0.90 with respect to the groove depth Dcl of the central lateral groove. It is preferable to satisfy. It is preferable that the groove depth GDc of the central main groove satisfies the relationship 0.85 ⁇ GDc / GDs ⁇ 1.00 with respect to the groove depth GDs of the outer main groove.
  • the groove depth Dcl of the central lateral groove is equal to the groove depth Dsl of the outer lateral groove. It is preferable that the relationship of 0.50 ⁇ Dcl / Dsl ⁇ 1.00 is satisfied. Furthermore, it is preferable that all of the central lateral grooves formed on the inner side in the tire width direction than the outer main groove have a groove width of 1.0 mm or less. Alternatively, it is preferable that all the grooves except the central main groove and the outer main groove formed in the tread portion have a groove width of 1.0 mm or less.
  • a pneumatic tire is filled with an air pressure of 230 kPa, and the tires in the circumferential direction when grounded under the conditions of loading 40%, 75%, and 100% of the maximum load capacity defined by the standard, respectively.
  • the maximum contact lengths are LA1, LB1, and LC1, respectively
  • the maximum contact widths in the tire width direction are WA1, WB1, and WC1, respectively
  • the maximum contact lengths LA1, LB1, and LC1 and the external contact lengths LA2, LB2, and LC2 are 1.02 ⁇ (LB2 / LB1) / (LA2 / LA1) ⁇ 1.25, 1.00 ⁇ (LC2 / LC1) / (LB2 / LB1) ⁇ 1.20, 0.75 ⁇ LB2 / It is preferable to satisfy the relation B1 ⁇ 1.00.
  • the tread portion when the tread portion includes a plurality of belt cords that are inclined with respect to the tire circumferential direction, and a plurality of belt layers in which the belt cords intersect with each other are embedded, It is preferable that the inclination angle ⁇ with respect to the tire circumferential direction satisfies the relationship of 21 ° ⁇ ⁇ ⁇ 30 °.
  • the load dependency of the cornering power is controlled by suppressing the increase in the rigidity of the belt layer, and the linearity of steering stability is further improved. Can do.
  • the inclination angle ⁇ of the belt cord with respect to the tire circumferential direction at the tire center position and the inclination angle ⁇ of the belt cord with respect to the tire circumferential direction at the belt end position satisfy the relationship of 18 ° ⁇ ⁇ ⁇ 30 °. Is preferred.
  • the inclination angle ⁇ at the belt end position of the belt cord to a small value, shoulder uneven wear can be suppressed, and the increase in rigidity of the belt layer in the central region of the tread is suppressed, and the cornering power depends on the load.
  • the controllability can be controlled and the linearity of steering stability can be further improved.
  • the pneumatic tire of the present invention is preferably a passenger car tire having an aspect ratio of 0.65 or less.
  • ADVANTAGE OF THE INVENTION According to this invention, in the tire for passenger cars in which the linearity of steering stability is requested
  • the cornering power is set such that the camber angle is set to 0 °, the speed is set to 10 km / h under the condition that a predetermined load is applied in a state where a tire is assembled on a regular rim and a predetermined air pressure is filled.
  • the cornering force is measured while changing the angle, and is calculated based on the cornering force in the range where the slip angle is 0 ° to 1 °.
  • the ground contact shape of the tread portion is measured under a condition in which a tire is assembled on a regular rim and filled with a predetermined air pressure, placed vertically on a plane and loaded with a predetermined load.
  • the outer diameter of the pneumatic tire is measured at the tire center position in a state where the tire is assembled on a regular rim and filled with a predetermined air pressure.
  • the “regular rim” is a rim determined for each tire in the standard system including the standard on which the tire is based, for example, a standard rim for JATMA, “Design Rim” for TRA, or ETRTO. Then, “Measuring Rim” is set.
  • the air pressure is 230 kPa.
  • the predetermined load is a load of 40%, 75% or 100% of the maximum load capacity defined by each standard for each tire in a standard system including the standard on which the tire is based.
  • FIG. 1 is a meridian cross-sectional view showing a pneumatic tire according to an embodiment of the present invention.
  • FIG. 2 is a development view showing a tread pattern of the pneumatic tire of FIG.
  • FIG. 3 is a plan view showing a ground contact shape (40% load) of the pneumatic tire of FIG.
  • FIG. 4 is a plan view showing a ground contact shape (75% load) of the pneumatic tire of FIG.
  • FIG. 5 is a plan view showing a ground contact shape (100% load) of the pneumatic tire of FIG. 6 is a cross-sectional view showing a central main groove, an outer main groove, and an outer lateral groove (lug groove) formed in the tread portion of the pneumatic tire of FIG.
  • FIG. 7 is a cross-sectional view showing a central lateral groove (lag groove) formed in the tread portion of the pneumatic tire of FIG.
  • FIG. 8 is a cross-sectional view showing an outer lateral groove (lag groove) formed in the tread portion of the pneumatic tire of FIG.
  • FIG. 9 is a development view showing a tread pattern of a pneumatic tire according to another embodiment of the present invention.
  • FIG. 10 is a development view showing a tread pattern of a pneumatic tire according to still another embodiment of the present invention.
  • FIG. 11 is a cross-sectional view showing a central lateral groove (sipe) formed in the tread portion of the pneumatic tire of FIGS. 9 and 10.
  • FIG. 12 is a cross-sectional view showing a modification of the central lateral groove (sipe).
  • FIG. 13 is a development view showing a belt layer constituting the pneumatic tire of the present invention.
  • FIG. 1 and 2 show a pneumatic tire according to an embodiment of the present invention.
  • CL is a tire center position
  • Tc is a tire circumferential direction
  • Tw is a tire width direction.
  • the pneumatic tire of the present embodiment includes a tread portion 1 that extends in the tire circumferential direction and has an annular shape, and a pair of sidewall portions 2, 2 disposed on both sides of the tread portion 1. And a pair of bead portions 3 and 3 disposed inside the sidewall portion 2 in the tire radial direction.
  • the carcass layer 4 is mounted between the pair of bead portions 3 and 3.
  • the carcass layer 4 includes a plurality of carcass cords extending in the tire radial direction, and is folded back from the inside of the tire to the outside around the bead core 5 disposed in each bead portion 3.
  • a bead filler 6 made of a rubber composition having a triangular cross-section is disposed on the outer periphery of the bead core 5.
  • a plurality of belt layers 7 are embedded on the outer peripheral side of the carcass layer 4 in the tread portion 1.
  • These belt layers 7 include a plurality of belt cords inclined with respect to the tire circumferential direction, and are arranged so that the belt cords cross each other between the layers.
  • a steel cord is preferably used as the belt cord constituting the belt layer 7.
  • an organic fiber cord such as nylon or aramid is preferably used as the band cord constituting the belt reinforcing layer 8.
  • the tread portion 1 includes a pair of central main grooves 11, 11 extending in the tire circumferential direction at positions on both sides of the tire center position CL, and the tire main body 11, 11 outside the central main grooves 11, 11.
  • a pair of outer main grooves 12 and 12 extending in the tire circumferential direction at the position are formed.
  • the central main groove 11 and the outer main groove 12 may have a straight shape or may have a zigzag shape.
  • a center land portion 20 is defined between the central main grooves 11 and 11, and a middle land portion 30 is defined between the central main groove 11 and the outer main groove 12.
  • a shoulder land portion 40 is defined in the area.
  • a plurality of central lateral grooves 31 extending in the tire width direction are formed in each of the middle land portions 30.
  • the central lateral groove 31 includes a central lug groove 31A having a groove width on the tread surface in the range of 1.1 mm to 9.0 mm and a central sipe 31B having a groove width on the tread surface of 1.0 mm or less. .
  • the central lug grooves 31A and the central sipes 31B are alternately arranged along the tire circumferential direction.
  • a circumferential narrow groove 32 extending in the tire circumferential direction and having a zigzag shape is formed on one side of the middle land portion 30.
  • Each of the shoulder land portions 40 is formed with a plurality of outer lateral grooves 41 extending in the tire width direction.
  • the outer lateral groove 41 includes at least one of an outer lug groove 41A having a groove width of 1.1 mm to 9.5 mm on the tread surface and an outer sipe 41B having a groove width of 1.0 mm or less on the tread surface. Yes.
  • the outer lug grooves 41A and the outer sipes 41B are alternately arranged along the tire circumferential direction.
  • the loads corresponding to 40%, 75% and 100% of the maximum load capacity defined by the standards are W40, W75 and W100 (kN), respectively, and the pneumatic tire is filled with an air pressure of 230 kPa.
  • the cornering powers measured under the conditions of loads W40, W75, and W100 are CP40, CP75, and CP100 (kN / °), respectively, the flatness ratio of the pneumatic tire is R, and the outer diameter is D (mm). And the nominal cross-sectional width is A (mm).
  • the loads W40, W75, W100 and the cornering powers CP40, CP75, CP100 are 0.05 ⁇ (R ⁇ D / 2A) 2 ⁇ [(CP100 ⁇ CP75) / (W100 ⁇ W75)] / [(CP75 ⁇ CP40) / (W75 ⁇ W40)] ⁇ 0.50 is satisfied.
  • FIGS. 3 to 5 show the ground contact shapes (40% load, 75% load, 100% load) of the pneumatic tire of FIG. 1, respectively.
  • the maximum contact length in the circumferential direction is LA1, LB1, LC1 (mm)
  • the maximum contact width in the tire width direction is WA1, WB1, WC1 (mm)
  • External contact lengths in the tire circumferential direction at positions 40% of the widths WA1, WB1, and WC1 are LA2, LB2, and LC2 (mm), respectively.
  • the maximum in the tire circumferential direction when the pneumatic tire is filled with 230 kPa of air pressure and contacted with a load of 40% of the maximum load capacity defined in the standard is applied.
  • the contact length is LA1
  • the maximum contact width in the tire width direction is WA1
  • the external contact length in the tire circumferential direction at a position 40% of the maximum contact width WA1 from the tire center position CL toward the outer side in the tire width direction is LA2.
  • the external ground contact length LA2 is an average value of measured values on both sides of the tire center position CL.
  • the contact length is LB1
  • the maximum contact width in the tire width direction is WB1
  • the external contact length in the tire circumferential direction at a position 40% of the maximum contact width WB1 from the tire center position CL toward the outer side in the tire width direction is LB2.
  • the external contact length LB2 is an average value of measured values on both sides of the tire center position CL.
  • the contact length is LC1
  • the maximum contact width in the tire width direction is WC1
  • the external contact length in the tire circumferential direction at the position of 40% of the maximum contact width WC1 from the tire center position CL toward the outer side in the tire width direction is LC2.
  • the external contact length LC2 is an average value of measured values on both sides of the tire center position CL.
  • the tread portion 1 includes a tire having a width corresponding to 53% of the maximum ground contact width WB1 around the tire equator (that is, the tire center position CL) and the tire within the maximum ground contact width WB1 than the center region Xc.
  • the groove area Sc (mm 2 ) of the central region Xc and the groove area Ss (mm 2 ) of the outer region Xs satisfy the following relationship. 0.80 ⁇ Sc / Ss ⁇ 0.98
  • the groove area Sc of the central region Xc means the total area of the groove components formed in the central region Xc on the tire circumference
  • the groove area Ss of the outer region Xs is the groove component formed in the outer region Xs on the tire circumference. It means the total area.
  • the groove component has a chamfered portion
  • the area of the chamfered portion is also included in the total area of the groove component.
  • the groove area Sc of the central region Xc and the groove area Ss of the outer region Xs satisfy the relationship of 0.80 ⁇ Sc / Ss ⁇ 0.98, and the groove area Sc in the central region Xc is By reducing it, the rigidity in the center area
  • the loads W40, W75, W100 and the cornering powers CP40, CP75, CP100 are 0.05 ⁇ (R ⁇ D / 2A) 2 ⁇ [(CP100 ⁇ CP75) / (W100 ⁇ W75)] / [(CP75 ⁇ CP40) /(W75 ⁇ W40)] ⁇ 0.50 is satisfied, it is possible to suppress an excessive increase in cornering power in the high load region.
  • the tire moves without delay from the initial steering of the steering wheel, and an appropriate cornering power is exhibited as the load increases, so that the linearity of steering stability can be improved. That is, it is possible to provide a tire in which yaw does not suddenly rise after a few seconds after inputting a constant turning steering.
  • the maximum contact lengths LA1, LB1, and LC1 and the external contact lengths LA2, LB2, and LC2 may satisfy the following relationship. 1.02 ⁇ (LB2 / LB1) / (LA2 / LA1) ⁇ 1.25 1.00 ⁇ (LC2 / LC1) / (LB2 / LB1) ⁇ 1.20 0.75 ⁇ LB2 / LB1 ⁇ 1.00
  • LA2 / LA1 means the rectangular ratio at 40% load
  • LB2 / LB1 means the rectangular ratio at 75% load
  • LC2 / LC1 means the rectangular ratio at 100% load.
  • the value of (LB2 / LB1) / (LA2 / LA1) is specified as an index for controlling the ground contact shape in the low load area
  • (LC2 / LC1) / By defining the value of (LB2 / LB1), the linearity of steering stability can be improved more precisely.
  • LB2 / LB1 in order to extend the wear life, it is desirable to set LB2 / LB1 within the above range under a load condition of 75% that is regarded as a general service load.
  • LB2 / LB1 When LB2 / LB1 is smaller than 0.75, the wear life is shortened. Conversely, when LB2 / LB1 is larger than 1.00, it is difficult to tune the linearity of steering stability. In particular, it is desirable to satisfy the relationship of 0.80 ⁇ LB2 / LB1 ⁇ 0.95.
  • the central main groove 11 extending in the tire circumferential direction
  • the outer main groove 12 extending in the tire circumferential direction at a position outside the central main groove 11 in the tire width direction, and the outer main groove 12.
  • the rigidity in the central region Xc of the tread portion 1 is secured.
  • the structure shown in FIGS. 6 to 8 can be employed in order to suppress the center uneven wear of 1 and to ensure high cornering power from a low load range.
  • the inclination angle ⁇ cl formed by the side wall of the central lateral groove 31 (particularly, the central lug groove 31A) with respect to the normal line of the tread surface should satisfy the relationship of 0 ° ⁇ ⁇ cl ⁇ 10 °.
  • the rigidity in the central region Xc of the tread portion 1 can be ensured.
  • ⁇ cl is smaller than 0 ° and the side wall has an overhang shape, the rigidity in the central region Xc is lowered.
  • it is larger than 10 ° the drainage is adversely affected.
  • the groove depth Dcl of the central transverse groove 31 should satisfy the relationship of 0.20 ⁇ Dcl / GDc ⁇ 0.90 with respect to the groove depth GDc of the central main groove 11.
  • region Xc of the tread part 1 is securable.
  • Dcl / GDc is smaller than 0.20, the drainage performance is adversely affected.
  • Dcl / GDc is larger than 0.90, the rigidity in the central region Xc is lowered.
  • the central lateral groove 31 (particularly, the central lug groove 31A) has a bottom raised portion 33 in a part of its longitudinal direction, and the groove depth Da at the bottom raised portion 33 is 0. 0 relative to the groove depth Dcl of the central lateral groove 31. It is preferable that the relationship of 20 ⁇ Da / Dcl ⁇ 0.90 is satisfied.
  • the bottom raised portion 33 is disposed at a position opening adjacent to the outer main groove 12. By providing such a raised portion 33, the rigidity in the central region Xc of the tread portion 1 can be ensured.
  • Da / Dcl is greater than 0.90, the effect on rigidity is reduced, and conversely if it is less than 0.20, drainage is adversely affected.
  • the groove depth GDc of the central main groove 11 should satisfy the relationship of 0.80 ⁇ GDc / GDs ⁇ 1.00 with respect to the groove depth GDs of the outer main groove 12. Thereby, the rigidity in the center area
  • GDc / GDs is smaller than 0.80, the drainage is adversely affected.
  • GDc / GDs is larger than 1.00, it is difficult to ensure rigidity in the central region Xc of the tread portion 1. .
  • the groove depth Dcl of the central lateral groove 31 is the groove depth of the outer lateral grooves 41. It is preferable to satisfy a relationship of 0.50 ⁇ Dcl / Dsl ⁇ 1.00 with respect to Dsl (see FIGS. 7 and 8). Thereby, the rigidity in the center area
  • Dcl / Dsl is smaller than 0.50, the drainage is adversely affected.
  • Dcl / Dsl is larger than 1.00, it is difficult to ensure rigidity in the central region Xc of the tread portion 1. .
  • FIG. 9 and 10 each show a tread pattern of a pneumatic tire according to another embodiment of the present invention.
  • 9 and 10 the same components as those in FIG. 2 are denoted by the same reference numerals, and detailed description thereof is omitted.
  • all of the central lateral grooves 31 formed on the inner side in the tire width direction from the outer main groove 12 are constituted by a central sipe 31B having a groove width of 1.0 mm or less.
  • the rigidity in the central region Xc of the tread portion 1 is ensured, the center uneven wear is suppressed, and from the low load region. High cornering power can be secured.
  • the circumferential narrow groove 32 formed on the inner side in the tire width direction from the outer main groove 12 is also configured to have a groove width of 1.0 mm or less.
  • all the grooves excluding the central main groove 11 and the outer main groove 12 formed in the tread portion 1 have a groove width of 1.0 mm or less. In this case, rigidity can be ensured over the entire area of the tread portion 1.
  • the central sipe 31B may have a constant groove width from the tread surface to the groove bottom as shown in FIG. 11, or, as shown in FIG. 12, the chamfered portion 34 is formed at the opening to the tread surface. You may have.
  • a similar structure can be adopted for the outer sipe 41B.
  • the tread portion 1 when the tread portion 1 includes a plurality of belt cords C that are inclined with respect to the tire circumferential direction, and a plurality of belt layers 7 in which the belt cords C cross each other are embedded, As shown in FIG. 13, the inclination angle ⁇ of the belt cord C with respect to the tire circumferential direction at the tire center position CL preferably satisfies the relationship of 21 ° ⁇ ⁇ ⁇ 30 °.
  • the inclination angle ⁇ of the belt cord C at the tire center position CL By not reducing the inclination angle ⁇ of the belt cord C at the tire center position CL extremely, the increase in rigidity of the tread portion 1 caused by the belt layer 7 is suppressed, and the load dependency of the cornering power is controlled and controlled. The stability linearity can be further improved.
  • the inclination angle ⁇ is smaller than 21 °, it becomes difficult to control the linearity of the steering stability due to the increase in rigidity of the belt layer 7, and conversely if it is larger than 30 °, the cornering characteristics and the like are deteriorated. Not right.
  • the inclination angle ⁇ of the belt cord C with respect to the tire circumferential direction at the tire center position CL and the inclination angle ⁇ of the belt cord C with respect to the tire circumferential direction at the belt end position BE have a relationship of 18 ° ⁇ ⁇ ⁇ 30 °. It is good to be satisfied.
  • shoulder uneven wear can be suppressed, and the inclination angle ⁇ of the belt cord C at the tire center position CL can be extremely reduced.
  • the difference between the inclination angle ⁇ and the inclination angle ⁇ is preferably 3 ° or more.
  • a structure in which the inclination angle ⁇ of the belt cord C with respect to the tire circumferential direction at the belt end position BE is smaller than the inclination angle ⁇ of the belt cord C with respect to the tire circumferential direction at the tire center position CL is preferable.
  • the belt cord C may be inclined at a constant angle with respect to the tire circumferential direction over the entire width, and the inclination angles ⁇ and ⁇ may be set to the same value, or ⁇ ⁇ .
  • the belt layer 7 has a high angle region Ac on the center side in which the inclination angle of the belt cord C is in the range of ⁇ ⁇ 1 ° and a shoulder in which the inclination angle of the belt cord C is in the range of ⁇ ⁇ 1 °.
  • the low-angle region As on the side, the width Lc of the high-angle region Ac is 1 ⁇ 2 or more of the total width L of the belt layer 7, and the width Ls of each low-angle region As is 1 of the total width L of the belt layer 7. It is good that it is / 8 or more.
  • the rigidity distribution of the tread portion 1 can be optimized.
  • the width Lc of the high angle region Ac is smaller than 1 ⁇ 2 of the entire width L of the belt layer 7, the function as the belt layer 7 is deteriorated, and the width Ls of the low angle region As is the entire width of the belt layer 7. If it is smaller than 1/8 of L, the rigidity in the tire circumferential direction in the outer region Xs of the tread portion 1 cannot be sufficiently increased.
  • the width Lc of the high angle area Ac and the width Ls of the low angle area As are set based on the total width L of each belt layer 7.
  • the pneumatic tire described above is suitable as a tire for passenger cars having a flatness ratio of 0.65 or less.
  • a tire for a passenger car in which linearity of steering stability is strictly required it is possible to achieve both uneven wear resistance and steering stability.
  • a tread pattern including four main grooves in the tread portion has been described.
  • the present invention includes a tread pattern including three main grooves in the tread portion, and a V-shaped main groove in the tread portion. It is applicable also to the tread pattern which contains.
  • a carcass layer is mounted between a pair of bead portions, two belt layers are embedded outside the carcass layer in the tire radial direction of the tread portion, and the tread portion extends in the tire circumferential direction.
  • the tire circumference at the tire cord center position of the belt cord The inclination angle ⁇ with respect to the direction, the inclination angle ⁇ with respect to the tire circumferential direction at the belt end position of the belt cord, the groove depth GDs of the outer main groove, the groove depth Dsl of the outer lateral groove, and the ratio GDc / G s, inclination angle ⁇ cl of the side wall of the central lateral groove, groove depth GDc of the central main groove, groove depth Dcl of the central lateral groove, ratio Dcl / GDc, groove depth Da at the raised portion of the central lateral groove, ratio Da / Dcl, Ratio Dcl / Dsl, groove width of the central lateral groove, groove width of the outer lateral groove, ratio Sc / Ss of the groove
  • Uneven wear resistance shoulder region, center region: Each test tire is mounted on a wheel with a rim size of 16 ⁇ 6.5J and mounted on a friction energy measurement tester. Under the conditions of air pressure of 230 kPa and load load of 4.5 kN, average friction in the shoulder region and center region of the tread portion Energy was measured. The measured values are obtained by measuring the frictional energy at a total of four points of 2 locations in the tire width direction ⁇ 2 locations in the tire circumferential direction, which are 10 mm intervals in each region, and averaging them.
  • the evaluation result uses the reciprocal of the measured value, and the uneven wear resistance in the shoulder region is indicated by an index with Comparative Example 1 as 100, and the uneven wear resistance in the center region is an index with Comparative Example 2 as 100. Showed. The larger the index value, the better the uneven wear resistance.
  • Steering stability linearity Each test tire is mounted on a wheel with a rim size of 16 x 6.5 J and mounted on a front-wheel drive vehicle with a displacement of 2 liters. The vehicle is filled with the specified air pressure, and a running test is conducted by a paneler on a test course consisting of a paved road. Then, sensory evaluation was performed on the linearity of steering stability. The evaluation results are shown as an index with Comparative Example 1 as 100. The larger the index value, the better the linearity of steering stability.

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  • Tires In General (AREA)

Abstract

L'invention concerne un pneu qui peut supprimer une usure centrale irrégulière dans une bande de roulement et améliorer la linéarité de la stabilité de direction. Les puissances en virage CP40, CP75 et CP100 (kN/°), qui sont respectivement obtenues par des mesures selon la condition que les charges W40, W75, W100 (kN) correspondant respectivement à 40 %, 75 %, et 100 % d'une capacité de transport de charge maximale standard stipulée sont appliquées à un pneu rempli de 230 kPa d'air, un rapport d'aspect R, un diamètre extérieur D (mm) et une largeur de section nominale A (mm) satisfont la relation suivante : 0,05 ≤ (R × D/2A) 2× [(CP100 - CP75)/(W100 - W75)]/[(CP75 - CP40)/(W75 - W40)] ≤ 0,50. Lorsqu'une bande de roulement (1) est divisée en une région centrale ayant une largeur correspondant à 53 % de la largeur de contact de masse maximale WB1 avec la charge W75 appliquée et des régions extérieures qui sont à l'extérieur de la région centrale, la zone de rainure Sc de la région centrale et les zones de rainure Ss des régions extérieures satisfont la relation suivante : 0,80 ≤ Sc/Ss ≤ 0,98.
PCT/JP2018/009070 2018-03-08 2018-03-08 Pneu WO2019171553A1 (fr)

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JP2019162912A (ja) * 2018-03-19 2019-09-26 横浜ゴム株式会社 空気入りタイヤ
JP2020032888A (ja) * 2018-08-30 2020-03-05 横浜ゴム株式会社 空気入りタイヤ
USD913204S1 (en) 2020-03-25 2021-03-16 Omni United (S) Pte Ltd. Tire tread
WO2023042474A1 (fr) * 2021-09-17 2023-03-23 横浜ゴム株式会社 Pneumatique
WO2023042473A1 (fr) * 2021-09-17 2023-03-23 横浜ゴム株式会社 Pneumatique

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JP2011230737A (ja) * 2010-04-30 2011-11-17 Yokohama Rubber Co Ltd:The 空気入りタイヤ
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JP2019162912A (ja) * 2018-03-19 2019-09-26 横浜ゴム株式会社 空気入りタイヤ
JP7031401B2 (ja) 2018-03-19 2022-03-08 横浜ゴム株式会社 空気入りタイヤ
JP2020032888A (ja) * 2018-08-30 2020-03-05 横浜ゴム株式会社 空気入りタイヤ
JP7107104B2 (ja) 2018-08-30 2022-07-27 横浜ゴム株式会社 空気入りタイヤ
USD913204S1 (en) 2020-03-25 2021-03-16 Omni United (S) Pte Ltd. Tire tread
WO2023042474A1 (fr) * 2021-09-17 2023-03-23 横浜ゴム株式会社 Pneumatique
WO2023042473A1 (fr) * 2021-09-17 2023-03-23 横浜ゴム株式会社 Pneumatique

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