JP2007050779A - Tire/wheel assembly - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a tire/wheel assembly improved in run-flat durability, while maintaining good riding comfort. <P>SOLUTION: This tire/wheel assembly is formed by arranging an annular run-flat support 3 formed with a support surface 15 on the peripheral side thereof on a rim 1 inside a cavity part 2Y of a pneumatic tire 2. The peripheral end 15a of the support surface 15 of the run-flat support 3 is positioned in a range at 70-90% of cross sectional height SHa from the rim diameter position t to the inner surface i positioned on the equator surface CL of the pneumatic tire 2. Rigidity of the run-flat support 3 is set in a range at 60-90% of rigidity of the pneumatic tire 2. Reinforcing rubber members 12 are annularly arranged in the inner surface 11a of both of side wall parts 11 of the pneumatic tire 2 along the tire circumferential direction. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a tire / wheel assembly, and more particularly to a tire / wheel assembly designed to improve run flat durability.

  In recent years, an annular run-flat support body having an outer peripheral side formed on a support surface is arranged in a hollow portion of a pneumatic tire assembled with a rim, and a run-flat running is enabled by supporting a punctured tire with the support body. Many core-type tire / wheel assemblies have been proposed (see, for example, Patent Documents 1 and 2).

  In this core type tire / wheel assembly, the height of the run-flat support is kept low to some extent in order to avoid contact of the tread portion of the tire with the run-flat support during normal running. Therefore, the amount of deflection of the sidewall portion of the tire supported by the run flat support during run flat traveling is large.

  In particular, in a tire / wheel assembly having a high tire cross-section height and a wide RV or SUV tire, the sidewall portion of the tire is greatly bent locally during run-flat running, and the bent portion due to the repetition of the bending is repeated. There is a problem that the bent portion is likely to burst due to heat generation and the run flat durability is low.

Therefore, as a countermeasure, if the height of the run-flat support is increased in order to reduce the amount of deflection of the sidewall portion, the tire tread portion contacts the run-flat support during normal driving. Decrease significantly.
JP-A-10-297226 JP-T-2001-519279

  An object of the present invention is to provide a tire / wheel assembly capable of improving run-flat durability while maintaining good riding comfort.

  The present invention that achieves the above-described object is a tire in which a pneumatic tire is mounted on a rim of a wheel, and an annular run-flat support body having an outer peripheral side formed on a support surface is disposed on a rim in a cavity of the pneumatic tire. In the wheel assembly, the outer peripheral end of the support surface of the run-flat support is positioned in the range of 70 to 90% of the cross-sectional height from the rim diameter position to the inner surface located on the equator plane of the pneumatic tire, The run-flat support has a rigidity set in a range of 60 to 90% of the rigidity of the pneumatic tire, and reinforcing rubber members are annularly arranged along the tire circumferential direction on the inner surfaces of both sidewall portions of the pneumatic tire. It is characterized by that.

  According to the above-described present invention, the tread portion of the pneumatic tire is brought into contact with the run-flat support during normal running by setting the outer peripheral end of the support surface of the run-flat support to a position of 90% or less of the cross-sectional height. On the other hand, by reducing the rigidity of the run flat support to 90% or less of the rigidity of the pneumatic tire, the pneumatic tire may be greatly bent during normal driving, and the tread portion may contact the run flat support. However, the ride comfort will not be greatly impaired.

  In addition, since the outer peripheral end of the support surface of the run flat support is at a position higher than 70% of the cross-sectional height above the conventional level, the sidewall portion of the pneumatic tire supported by the run flat support during run flat travel The amount of bending can be made smaller than before. As a result, the local bending at the sidewall portion is reduced, and it is possible to suppress the burst of the bending portion due to heat generation or the like.

  On the other hand, the durability of the run-flat support is lowered in order to reduce the rigidity of the run-flat support, but the rigidity of the run-flat support is maintained at 60% or more of the rigidity of the pneumatic tire, while the reduced amount Is made up by a reinforcing rubber member provided on the inner surface of the sidewall portion, so that it is possible to avoid a decrease in durability due to breakage of the run-flat support.

  Therefore, the run flat durability can be improved while maintaining good riding comfort.

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings.
FIG. 1 is a meridian cross-sectional view showing a main part of a tire / wheel assembly according to an embodiment of the present invention. Reference numeral 1 denotes a wheel rim, 2 is a pneumatic tire, and 3 is a run-flat support. The rim 1, the pneumatic tire 2, and the run-flat support 3 are formed in an annular shape coaxially with a wheel rotation center axis (not shown) as a center, and on the rim 1 in the cavity 2 </ b> Y of the pneumatic tire 2 attached to the rim 1. It is the structure which has arrange | positioned the run-flat support body 3 in this.

  The pneumatic tire 2 has a carcass layer 5 extending between the left and right bead portions 4. Both ends of the carcass layer 5 are folded back from the inside to the outside of the tire so as to sandwich a bead filler 7 around a bead core 6 embedded in the bead portion 4. Two belt layers 9 are disposed on the outer peripheral side of the carcass layer 5 of the tread portion 8, and a belt cover layer 10 is provided on the outer peripheral side thereof.

  On the tread portion 8 side of the inner surfaces 11a of both sidewall portions 11, a reinforcing rubber member 12 is annularly extended along the tire circumferential direction. In FIG. 1, the reinforcing rubber member 12 is a single-layer rubber member projecting from the inner surface 11a. However, as shown in FIG. 2, a plurality of convex bodies 12a extending annularly in the tire circumferential direction are provided. A bellows-like rubber member connected in the tire radial direction may be used, and as shown in FIG. 3, convex portions 12b extending in the tire radial direction are annularly arranged on the inner surface 11a at predetermined intervals in the tire circumferential direction. A rib-shaped rubber member may be used.

  The cross-sectional shape of the reinforcing rubber member 12 is preferably approximately crescent. The reinforcing rubber member 12 is composed of only rubber in the illustrated example, but the rubber may contain a reinforcing material such as short fiber.

  The run-flat support 3 includes an annular shell 13 formed from a rigid material such as metal or resin, and left and right elastic rings 14 formed from an elastic material such as rubber or elastic resin. The annular shell 13 forms a support surface 15 having two convex curved surfaces 15A having a radius of curvature on the outer peripheral side in the shell width direction. The support surface 15 is a tread portion 8 of a tire that is crushed when the pneumatic tire 2 is punctured. It comes to support. On the inner peripheral side of the annular shell 4, both side walls are legged as leg portions 16, and an elastic ring 14 is attached to the inner peripheral side.

  The run-flat support 3 is positioned in the range of 70 to 90% of the cross-sectional height SHa from the outer peripheral end 15a of the support surface 15 to the inner surface i positioned on the equator plane CL of the pneumatic tire 2 from the rim diameter position r. The height of the run flat support 3 is made higher than before. Further, the rigidity of the run-flat support 3 is set in a range of 60 to 90% of the rigidity of the pneumatic tire 2. Here, the rigidity of the pneumatic tire 2 and the rigidity of the run-flat support 3 are defined as follows.

  The rigidity of the pneumatic tire 2 was pressed while gradually increasing the load load on the test surface of the tread surface of the pneumatic tire 2 assembled with the rim under the conditions of the standard rim specified by JATMA and the air pressure corresponding to the maximum load capacity. In the graph in which the change in compression amount (mm) is measured, and the horizontal axis represents the compression amount and the vertical axis represents the load load, the slope of the linearly changing portion is the stiffness of the pneumatic tire 2 Is an index that represents The rigidity of the run-flat support 3 is the same as that described above in the state of being mounted on the standard rim (the same as the state of being mounted on the tire / wheel assembly). It is an index to represent. The greater the inclination, the higher the rigidity.

  According to the present invention described above, the outer peripheral end 15a of the support surface 15 of the run-flat support 3 is positioned at 90% or less of the cross-sectional height SHa, so that the tread portion 8 of the pneumatic tire 2 can be run during normal running. By avoiding contact with the flat support 3 and further reducing the rigidity of the run-flat support 3 to 90% or less of the rigidity of the pneumatic tire 2, the pneumatic tire 2 is greatly bent during normal running, and the tread portion 8. Even if there is a case in which the run-flat support 3 comes into contact with the run-flat support 3, the riding comfort is not greatly impaired.

  Further, by setting the outer peripheral end 15a of the support surface 15 of the run flat support 3 to a position higher than 70% of the sectional height SHa, which is higher than the conventional level, the pneumatic tire supported by the run flat support 3 during the run flat running. The amount of bending of the second sidewall portion 11 can be suppressed. Therefore, the local bending in the sidewall portion 11 becomes smaller than in the conventional case, and the bending portion can be prevented from bursting due to heat generation or the like.

  On the other hand, the durability of the run flat support 3 is reduced by lowering the rigidity of the run flat support 3, but the rigidity of the run flat support 3 is maintained at 60% or more of the rigidity of the pneumatic tire 2, Since the reduced amount is supplemented by the reinforcing rubber member 12, it is possible to prevent a decrease in durability due to breakage of the run-flat support 3.

Therefore, the run flat durability can be improved while maintaining good riding comfort.
When the outer peripheral edge 15a of the support surface 15 of the run flat support 3 is at a position less than 70% of the cross-sectional height SHa, the sidewall portion 11 of the pneumatic tire 2 supported by the run flat support 3 during run flat travel. It becomes impossible to effectively suppress the amount of bending. On the other hand, if the position exceeds 90%, the tread portion 8 of the pneumatic tire 2 is likely to come into contact with the run-flat support 3 during normal running.

  If the rigidity of the run-flat support 3 is less than 60% of the rigidity of the pneumatic tire 2, the run-flat support 3 is likely to be damaged during run-flat travel. On the other hand, if it exceeds 90%, when the tread portion 8 comes into contact with the run-flat support 3 during normal running, there is a feeling of bottoming and the riding comfort is lowered.

  In the present invention, the reinforcing rubber member 12 is disposed in the side wall portion inner surface region Z located between the position P of 50% of the sectional height SH of the pneumatic tire 2 and the end portion of the belt layer 9, and the reinforcing rubber The tire radial width W1 of the member 12 is preferably in the range of 40 to 100% of the tire radial width W2 of the sidewall portion inner surface region Z. In addition, the position Q on the tire radial direction outer side of the sidewall portion inner surface area Z referred to here is the position of the intersection of the normal line n drawn from the edge E of the belt layer 9a having the widest width to the tire inner surface and the tire inner surface. It is.

  If the tire radial direction width W1 is less than 40% of the tire radial direction width W2 of the sidewall portion inner surface region Z, the reinforcing effect to compensate for the reduced rigidity of the run-flat support 3 becomes insufficient. If it exceeds 100%, the tire performance may be adversely affected due to an increase in weight. If the reinforcing rubber member 12 is disposed at a position outside the sidewall portion inner surface region Z, it is difficult to sufficiently exert a reinforcing effect that compensates for the reduced rigidity of the run-flat support 3 while suppressing an increase in weight. Become.

  The maximum thickness of the reinforcing rubber member 12 is preferably 1.0 to 3.0 times the minimum thickness of the sidewall portion 11. If the maximum thickness of the reinforcing rubber member 12 is less than 1.0 times the minimum thickness of the sidewall portion 11, the reinforcing effect that compensates for the reduced rigidity of the run-flat support 3 becomes insufficient. Conversely, if it exceeds 3.0 times, the tire performance may be adversely affected due to an increase in weight.

  As the reinforcing rubber member 12, the same rubber as that used for tire reinforcing members such as a belt layer and a carcass layer can be used. The various properties of the rubber composition are JIS-A hardness of 50 to 95, loss tangent tan δ of 0.05 to 0.3, and 100% modulus at a temperature of 20 ° C. of 0.5 to 15.0 MPa. The loss tangent tan δ is measured using a viscoelastic spectrometer (manufactured by Toyo Seiki Seisakusho) under conditions of a temperature of 60 ° C., a frequency of 20 Hz, an initial strain of 10%, and a dynamic strain of ± 2%.

  In the above-described embodiment, the tire / wheel assembly including the run-flat support body 3 including the annular shell 13 and the left and right elastic rings 14 has been described. However, the present invention is not limited to the rim in the hollow portion 2Y of the pneumatic tire 2. 1 is applicable to any tire / wheel assembly provided with a run-flat support of the type arranged on 1 and supporting a punctured tire during run-flat running with a support surface formed on the outer peripheral side. it can.

  The present invention is particularly preferable for a tire / wheel assembly equipped with a tire having a high tire cross-sectional height and a wide width, such as a tire for an RV (recreational vehicle), SUV (sport-utility vehicle), or LTR (light truck). Although it can be used, it is not limited thereto.

  The tire size is 215 / 65R16 and the rim size is 16 × 6 1 / 2JJ, and the run-flat support stiffness relative to the position of the outer peripheral edge of the support surface of the run-flat support and the stiffness of the pneumatic tire is as shown in Table 1. The tire / wheel assemblies 1 to 3 (Examples 1 to 3) and the comparative tire / wheel assemblies 1 to 4 (Comparative Examples 1 to 4) of the present invention having the configuration shown in FIG. A tire / wheel assembly (conventional example) was produced.

  The reinforced rubber member of the tire / wheel assembly of the present invention and the comparative tire / wheel assembly has a tire radial direction width of 60% of the tire radial direction width of the sidewall portion inner surface region and a maximum thickness of 2 which is the minimum thickness of the sidewall portion. Double and common.

  These test tire / wheel assemblies were mounted on a 2.5 liter SUV and subjected to an evaluation test of riding comfort and run-flat durability by the following measurement method. The results shown in Table 1 were obtained. It was.

Riding comfort Each test tire / wheel assembly was adjusted to an air pressure of 230 kPa, and a feeling test by a test driver was performed on the test course, and the evaluation result was shown as an index value with the conventional tire / wheel assembly as 100. The larger this value, the better the ride comfort.

Run-flat durability The test tire / wheel assembly attached as the front right wheel was set to 0 kPa, and the air pressure was set to 230 kPa, and the distance when the test course was run at 90 km / h until it became impossible to run was measured. The results are shown as index values with the conventional tire / wheel assembly as 100. The larger this value, the better the run flat durability.

  From Table 1, it can be seen that the tire / wheel assembly of the present invention can improve the run-flat durability while ensuring the same riding comfort as the conventional one.

It is principal part sectional drawing of one Embodiment of the tire / wheel assembly of this invention. It is sectional drawing which shows the other example of a reinforced rubber member. It is principal part perspective explanatory drawing which shows the further another example of a reinforced rubber member.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Rim 2 Pneumatic tire 2Y Cavity part 3 Run-flat support body 5 Carcass layer 8 Tread part 9, 9a Belt layer 11 Side wall part 11a Inner surface 12 Reinforcement rubber member 15 Support surface 15a Outer peripheral edge CL Equatorial plane P position SH, SH Cross section Height W1, W2 Tire radial width Z Side wall inner surface area i Inner surface r Rim diameter position

Claims (5)

In a tire / wheel assembly in which a pneumatic tire is mounted on a rim of a wheel, and an annular run-flat support body having an outer peripheral side formed on a support surface is disposed on a rim in a hollow portion of the pneumatic tire.
While the outer peripheral end of the support surface of the run flat support is positioned in the range of 70 to 90% of the cross-sectional height from the rim diameter position to the inner surface located on the equatorial plane of the pneumatic tire, the run flat support The tire / wheel assembly in which the rigidity of the pneumatic tire is set in a range of 60 to 90% of the rigidity of the pneumatic tire, and reinforcing rubber members are annularly arranged along the tire circumferential direction on the inner surfaces of both sidewall portions of the pneumatic tire Solid.   The pneumatic tire has a belt layer on the outer peripheral side of the carcass layer of the tread portion, and the reinforcing rubber member is located between a position of 50% of the sectional height of the pneumatic tire and an end of the belt layer. The tire / wheel assembly according to claim 1, wherein the tire / wheel assembly is disposed in an inner surface area of the sidewall portion.   The tire / wheel assembly according to claim 2, wherein a tire radial width of the reinforcing rubber member is 40 to 100% of a tire radial width of the sidewall portion inner surface region.   The tire / wheel assembly according to claim 1, 2 or 3, wherein the maximum thickness of the reinforcing rubber member is 1.0 to 3.0 times the minimum thickness of the sidewall portion.   The reinforcing rubber member is made of a rubber composition having a JIS-A hardness of 50 to 95, a loss tangent tan δ of 0.05 to 0.3, and a 100% modulus of 0.5 to 15.0 MPa. 5. The tire / wheel assembly according to 3 or 4.

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