JP2004161220A - Tire/wheel assembly body and run-flat supporting body - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a tire/wheel assembly body and a run-flat supporting body which facilitate the simultaneous rim assembly operation of a pneumatic tire and the run-flat supporting body. <P>SOLUTION: In the tire/wheel assembly body into which the run-flat supporting body 3, which comprises a ring-shaped shell 4 wherein the external peripheral side is used for a supporting face and the internal peripheral side is also forked into two legs and elastic rings 5 for supporting the forked end sections on the rim, is inserted, the elastic ring 5<SB>o</SB>positioned on the front side of a wheel out of the elastic rings 5 is provided with a part whose flexural rigidity in a tire axis direction is lower than that in a residual range in the peripheral length range of 1/4 to 1/2. <P>COPYRIGHT: (C)2004,JPO

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a tire / wheel assembly and a run flat support, and more particularly, to a tire / wheel assembly and a run flat support that facilitates rim assembly.
[0002]
[Prior art]
Many technologies have been proposed that enable emergency traveling of about several hundred km even when a pneumatic tire is punctured while the vehicle is running. Among these many proposals, the proposal in Patent Document 1 and the like is based on mounting a core on a rim inside a hollow portion of a rim-assembled pneumatic tire and supporting a punctured tire with the core to run flat. It made it possible to run. The run flat support has elastic rings attached to both legs of an annular shell having an outer peripheral side as a support surface, and is supported on a rim via the elastic rings. This run-flat support has the advantage that it can be used without any special modifications to existing wheels / rims, thus making it acceptable without disrupting the market.
[0003]
However, the run flat support has the above-mentioned advantages, but on the other hand, it becomes an obstacle when assembling the rim with the pneumatic tire at the same time, and causes a problem that rim assembling workability is deteriorated. That is, generally, the rim assembling work is performed as shown in FIG. 6, in which the run-flat support 3 is first inserted inside the pneumatic tire 2, and the bead positioned on the back side of the wheel 10 (inside when the vehicle is mounted). The portion 2b and the elastic ring 5 are set on the rim sheet 1s of the rim 1. Next, the bead portion 2b on the front side (outside when the vehicle is mounted) of the wheel 10 and the elastic ring 5o must be made to pass over the rim flange 1f.
[0004]
However, since the inner diameters of the bead portion 2b and the elastic ring 5o are smaller than the outer diameter of the rim flange 1f, the bead portion 2b and the elastic ring 5o are located on opposite sides of the tire shaft in order to get over this. One of the inner peripheral edges must be dropped into the rim drop 1d having the minimum radius, and the inner peripheral edge on the opposite side must be made radially clear so as to pass through the outer edge of the rim flange 1f.
[0005]
However, when the run flat support 3 is inserted inside the pneumatic tire 2 as described above, the run flat support 3 is used to drop one of the bead portion 2b and the inner peripheral edge of the elastic ring 5o into the rim drop 1d. The body 3 becomes a resistor, making the dropping operation extremely difficult. Therefore, simultaneous rim assembling operation of the pneumatic tire 2 and the run flat support 3 becomes difficult.
[0006]
[Patent Document 1]
JP 10-297226 A
[Problems to be solved by the invention]
SUMMARY OF THE INVENTION An object of the present invention is to provide a tire / wheel assembly and a run flat support that solve the above problems and facilitate simultaneous rim assembling operations of a pneumatic tire and a run flat support. is there.
[0008]
[Means for Solving the Problems]
To achieve the above object, a tire / wheel assembly according to the present invention provides an annular shell having a support surface on the outer peripheral side and a bifurcated inner peripheral side in a hollow portion of a pneumatic tire, and the bifurcated leg. In a tire / wheel assembly in which a run-flat support comprising an elastic ring supporting an end portion on a rim is inserted, one-quarter to one-half of the elastic ring located on the front side of the wheel among the elastic rings. A portion having a lower bending rigidity in the tire axial direction than the remaining region is provided over the circumferential length region.
[0009]
In addition, the run flat support of the present invention includes an annular shell having an outer peripheral side as a support surface and an inner peripheral side with a forked open leg, and an elastic ring for supporting the forked open leg end on a rim. A run-flat support comprising: an elastic ring, which is located on the front side of the wheel among the elastic rings, has a flexural rigidity in the tire axial direction that is smaller than that of the remaining region over a quarter of its circumference region. A low portion is provided.
[0010]
As described above, a portion having a lower flexural rigidity in the tire axial direction than the remaining region is provided in a region having a 1/4 to 1/2 circumference of the elastic ring located on the front side of the wheel. After the bead part and the elastic ring located on the back side are seated on the rim seat on the back side, the bead part and the elastic ring on the front side of the wheel are replaced with a part of the elastic ring having a low bending rigidity of 1/4 to 1/2 circumference. If the bead portion is pushed from the outside to the inside of the rim, the portion having low bending rigidity easily bends inward and can be dropped into the drop together with the bead portion.
[0011]
If the area of 1/4 to 1/2 circumference is dropped into the drop, it is easy to drop the entire elastic ring and bead portion into the drop thereafter. Then, when the tire pressure is increased by filling air as is well known, the bead portion and the elastic ring can ride on the rim seat and be seated.
[0012]
BEST MODE FOR CARRYING OUT THE INVENTION
In the present invention, the run flat support is formed as an annular body inserted into the cavity of the pneumatic tire. The run flat support is formed to have a smaller outer diameter than the inner diameter of the hollow portion so as to keep a constant distance from the inner surface of the hollow portion of the pneumatic tire, and the inner diameter is substantially the same as the inner diameter of the bead portion of the pneumatic tire. It is formed in dimensions. The run flat support is inserted into the pneumatic tire and rim assembled to the wheel together with the pneumatic tire to form a tire / wheel assembly. If the tire is punctured while the tire / wheel assembly is mounted on a vehicle and running, the punctured and crushed tire is supported on the outer peripheral surface of the run flat support, enabling run flat running. I do.
[0013]
The run flat support is mainly composed of an annular shell and an elastic ring. The annular shell forms a continuous support surface to support a punctured tire on the outer peripheral side (outer diameter side), and the inner peripheral side (inner diameter side) has a bifurcated shape with left and right side walls as legs. I have. The support surface on the outer peripheral side is formed such that the shape in a cross section orthogonal to the circumferential direction is a convex surface on the outer diameter side. The number of convex portions on the outer peripheral side of the annular shell may be one or two or more. However, when the number of protrusions is plural, the load supported during run flat traveling can be dispersed to the plurality of protrusions, so that the durability of the annular shell can be improved as a whole.
[0014]
The elastic rings are respectively attached to the ends of the bifurcated legs on the inner diameter side of the annular shell, and support the annular shell by abutting on the left and right rim sheets. The elastic ring is made of rubber or elastic resin, and reduces shocks and vibrations applied to the annular shell from a punctured tire and stably supports the annular shell by preventing the rim sheet from slipping.
[0015]
Since the run flat support of the present invention must support the weight of the vehicle via punctured tires, the annular shell is made of a rigid material. Metal, resin, and the like are used as the constituent materials. Examples of the metal include steel and aluminum. The resin may be either a thermoplastic resin or a thermosetting resin. Examples of the thermoplastic resin include nylon, polyester, polyethylene, polypropylene, polystyrene, polyphenylene sulfide, and ABS. Examples of the thermosetting resin include an epoxy resin and an unsaturated polyester resin. The resin may be used alone, or may be used as a fiber reinforced resin by blending reinforcing fibers.
[0016]
In the run flat support of the present invention, a part of the left and right elastic rings in the circumferential direction of the elastic ring located on the front side of the wheel is provided with a portion having a lower bending rigidity in the tire axial direction than the remaining region, By utilizing the portion having low bending rigidity, it is easy to drop into the rim drop in the simultaneous rim assembling work of the pneumatic tire and the run flat support.
[0017]
The reason why the elastic ring provided with the portion having low bending rigidity is an elastic ring located on the front side of the wheel is that a drop on the rim is generally formed closer to the front side of the wheel. Further, the reason why the portion having low bending rigidity is limited to the region of 1/4 to 1/2 circumference is that when the circumference is less than 1/4 circumference, bending deformation of the elastic ring in the axial direction is difficult to obtain. On the other hand, if the circumference exceeds 1/2, the support of the puncture tire becomes incomplete, and the run-flat running property becomes unstable.
[0018]
It is preferable to set the size of the portion having low bending rigidity as follows.
[0019]
As shown in FIG. 5, the run-flat support 3 is stably supported by the rigid support for measurement 10, and a load is applied to the inner peripheral end of the elastic ring 5 of the run-flat support 3 by a presser in the tire axial direction. When F = 20N is given and the bending stiffness R when the amount of deflection generated at that time is D mm is defined by R = F / D, the bending stiffness R of the portion where the bending stiffness is low is the bending stiffness of the remaining region. It is preferably set at least 7% lower than R, and the upper limit is preferably set to 40%. More preferably, it is good to make it into the range of 15 to 40%. If the difference in the bending stiffness R is less than 7%, it is difficult to improve the rim assemblability, and if it exceeds 40%, the run-flat running performance deteriorates.
[0020]
The means for reducing the axial bending stiffness of the elastic ring is not particularly limited. For example, a slit may be provided as described below, or a rubber or elastic resin having a lower hardness than other regions may be provided. The direction of the slit is not particularly limited, but may be a radial direction or a circumferential direction. When the bending stiffness in the axial direction is reduced in this way, the compression stiffness in the radial direction at that location should be substantially the same as the other parts in the circumferential direction so as not to impair run-flat running performance. And it is preferable that the decrease be kept to less than 5%.
[0021]
Hereinafter, the present invention will be specifically described with reference to the drawings.
[0022]
FIG. 1 is a tire width direction cross-sectional view (meridian cross-sectional view) showing a main part of a tire / wheel assembly (wheel) according to an embodiment of the present invention.
[0023]
1 is a rim on the outer periphery of the wheel, 2 is a pneumatic tire, and 3 is a support for run flat. The rim 1, the pneumatic tire 2, and the run flat support 3 are formed coaxially annularly around a rotation axis of a wheel (not shown).
[0024]
The run flat support 3 includes an annular shell 4 formed of a rigid material such as metal or resin, and an elastic ring 5 formed of an elastic material such as hard rubber or elastic resin. The annular shell 4 is formed so that convex portions 4a and 4b formed of two convex curved surfaces are arranged on the outer peripheral side in the tire width direction. Both side walls on the inner peripheral side of the annular shell 4 are bifurcated as legs 6, 6, and elastic rings 5, 5 are attached to ends thereof.
[0025]
With the run-flat support body 3 configured as described above, the elastic rings 5 and 5 are simultaneously attached to the rim sheets 1 s and 1 s of the rim 1 together with the bead portions 2 b and 2 b in a state of being inserted inside the pneumatic tire 2. Have been. A bead core 7 is annularly embedded in each bead portion 2b along the circumferential direction of the tire, and the embedding of the bead core 7 gives rigidity to the bead portion 2b. The bead core 7 is formed by winding a steel wire in a plurality of rounds.
[0026]
The run flat support 3 inserted in the tire / wheel assembly is configured as shown in FIG. Elastic rings 5 and 5 are attached to the left and right legs 6 and 6 of the run flat support 3, respectively. Among them, the elastic rings provided on the front side of the wheel (outside when the vehicle is mounted, left side in FIG. 1) are provided. 5o, a plurality of radial slits 8 are provided in the region of length L in the circumferential direction at a pitch p. By providing the plurality of slits 8, the bending rigidity in the tire axial direction in the region of the length L is lower than the bending rigidity in the remaining region.
[0027]
The slit 8 as a means for reducing the bending stiffness may penetrate the elastic ring 5o in and out, or may have a bottom stopped halfway, but is preferably the former. This is because, when a slit is formed, the portion between the two adjacent slits 8 is shaped like a plate supported on one side, so that it is easily bent against a load in the tire axial direction. In this case, it is preferable that the radial compression stiffness is maintained substantially uniform in the circumferential direction.
[0028]
The length L is set in the range of 1/4 to 1/2 circumference. When the bending stiffness is specified by the bending stiffness R defined above, the bending stiffness R in the region of the length L is set to be 7 to 40% lower than the bending stiffness R in the remaining region, and preferably 15 to 40. % Lower. In order to set such a bending rigidity, the pitch p of the slit 8 is preferably set to about 30 to 70 mm. Further, in order to set such a bending rigidity, in addition to providing the slit 8 in the region of the length L, the region may be formed of rubber or elastic resin having lower hardness than the remaining region.
[0029]
By providing the elastic ring 5o on the front side of the wheel with a portion having a low flexural rigidity R in the range of 1/4 to 1/2 circumference, the pneumatic tire 2 and the run flat support 3 are attached to the rim 1. When the rim is assembled simultaneously, the bead portion 2b on the front side of the wheel and the elastic ring 5o can be easily dropped into the rim drop 1d, so that the rim assemblability can be improved.
[0030]
FIG. 3 shows another embodiment of the run flat support of the present invention.
[0031]
In this embodiment, a circumferential slit 8 'is provided as means for lowering the bending stiffness of the elastic ring 5o located on the front side of the wheel in a region of 1/4 to 1/2 circumference. The slit 8 'may penetrate the inside and outside of the elastic ring 5o, or may have a bottom with a halfway depth. Further, the area where the slit 8 'is provided may be made of rubber or elastic resin having lower hardness than the remaining area.
[0032]
By providing the circumferential slit 8 'in the region of 1/4 to 1/2 circumference in this way, the bending rigidity R in this region is set to be 7 to 40% lower than the bending rigidity R in the remaining region. And the rim assemblability can be improved.
[0033]
FIG. 4 shows still another embodiment of the run flat support of the present invention.
[0034]
In this embodiment, the JIS-A hardness when the area 9 of the 1/4 to 1/2 circumference of the elastic ring 5o on the front side of the wheel is measured at a temperature of 25 ° C., that is, the JIS-A hardness (25 ° C.) Is formed of rubber or elastic resin of 50 to 65, preferably 53 to 60, and the rest of the remaining region has a JIS-A hardness (25 ° C.) greater than that of the rubber or elastic resin of region 9 by 5 points or more. Alternatively, it is formed of an elastic resin.
[0035]
By using a combination structure of two or more types of rubber or elastic resin, the bending rigidity R of the region 9 can be set to be 7 to 40% lower than the bending rigidity R of the remaining region. Simultaneous rim assembly workability of the tire and the run flat support can be improved.
[0036]
【The invention's effect】
As described above, according to the present invention, a portion having a lower flexural rigidity in the tire axial direction than the remaining region is provided in a region of 1/4 to 1/2 circumference of the elastic ring located on the front side of the wheel. Simultaneous dropping of the elastic ring located on the front side and the tire bead portion into the rim drop can be facilitated, and simultaneous rim assembling of the pneumatic tire and the run flat support can be improved.
[Brief description of the drawings]
FIG. 1 is a meridional sectional view showing a main part of a tire / wheel assembly according to an embodiment of the present invention.
FIG. 2 is a perspective view showing a main part of a run flat support incorporated in the tire / wheel assembly of FIG. 1;
FIG. 3 is a perspective view showing a main part of a run flat support according to another embodiment of the present invention.
FIG. 4 is a perspective view showing a main part of a run flat support according to still another embodiment of the present invention.
FIG. 5 is an explanatory view showing a method for measuring the bending stiffness of the elastic ring in the tire axial direction according to the present invention.
FIG. 6 is an operation explanatory diagram when a pneumatic tire and a run flat support are simultaneously assembled to a rim.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Rim 1d Drop (of rim) 2 Pneumatic tire 2b Bead part 3 Support for run flat 4 Annular shell 5 Elastic ring 5o Elastic ring 8, 8 'slit (located on the front side of wheel)

Claims (10)

A run-flat formed in a cavity of a pneumatic tire, an annular shell having an outer peripheral side as a support surface and an inner peripheral side opened in a forked shape, and an elastic ring for supporting the forked open leg on a rim. In the tire / wheel assembly in which the supporting body is inserted, the elastic ring located on the front side of the wheel among the elastic rings is bent in the tire axial direction more than the remaining area over a quarter of its circumference area. A tire / wheel assembly provided with a low rigidity portion. When the bending stiffness R is defined as F / D from the amount of deflection Dmm when a load F = 20 N is applied to the inner peripheral end of the elastic ring in the tire axial direction, the bending stiffness R of the low bending stiffness portion is calculated. 2. The tire / wheel assembly of claim 1 wherein said tire / wheel assembly is at least 7% lower than said remaining area. The tire / wheel assembly according to claim 1 or 2, wherein the portion having a low bending rigidity is formed by providing a plurality of radial slits. The tire / wheel assembly according to claim 1 or 2, wherein the portion having low bending rigidity is formed by providing a plurality of circumferential slits. The portion having a low flexural rigidity is formed of rubber or elastic resin having a JIS-A hardness (25 ° C.) of 50 to 65, and the remaining portion has a JIS-A hardness (25 ° C.) higher than that of the low portion rubber or elastic resin. The tire / wheel assembly according to claim 1, wherein the tire / wheel assembly is formed of a rubber or an elastic resin that is larger by 5 points or more. A run flat support comprising an annular shell having an outer peripheral side as a support surface and an inner peripheral side having a forked open leg and an elastic ring for supporting the forked open leg end on a rim, A run-flat support member in which an elastic ring located on the front side of the wheel among elastic rings is provided with a portion having a lower bending rigidity in the tire axial direction than a remaining region over a circumferential length region of 〜 to そ の thereof. When the bending stiffness R is defined as F / D from the amount of deflection Dmm when a load F = 20 N is applied to the inner peripheral end of the elastic ring in the tire axial direction, the bending stiffness R of the low bending stiffness portion is calculated. 7. The run-flat support of claim 6, wherein the support is at least 7% lower than the remaining area. The run flat support according to claim 6 or 7, wherein the portion having low bending rigidity is formed by providing a plurality of radial slits. The run flat support according to claim 6 or 7, wherein the portion having a low bending rigidity is formed by providing a plurality of circumferential slits. The portion having a low flexural rigidity is formed of rubber or elastic resin having a JIS-A hardness (25 ° C.) of 50 to 65, and the remaining portion has a JIS-A hardness (25 ° C.) higher than that of the low portion rubber or elastic resin. The run-flat support according to claim 6, wherein the support is formed of a rubber or an elastic resin having a size larger than 5 points.

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