JP2633832B2 - Wheel rim and tire assembly - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention is a tire that enables safe driving without the tire bead portion coming off the rim when the internal pressure of the tire is reduced or when sharp cornering is performed. And wheel rim assembly.

[Conventional technology]

Conventionally, in a tire and wheel rim assembly, a tire bead portion is held on a bead seat by a pressing force of a tire internal pressure and a frictional force of rubber between the bead seat and a tire bead bottom. Therefore, when the internal pressure of the tire is reduced, the holding force is reduced. However, when the steering wheel is suddenly turned in response to a sudden decrease in the internal pressure, such as during a puncture, a lateral force is generated due to the turning motion, and the tire is disengaged from the bead portion and becomes unstable. In particular, in the case of a rim having a well provided for mounting a tire, there is a risk that the timer may be completely disengaged from the rim and cause a serious accident. That is, the mechanism of the rim off the bead portion of the tire can be explained as follows.

The lateral force generated when cornering in driving a vehicle shifts the tread portion laterally with respect to the wheel rim and causes deformation, which is transmitted from the carcass to the bead portion. As a result, an axial (lateral) force and a rotational moment about the circumferential line of the bead are generated near the tire contact portion.

At this time, when the tire internal pressure is low, the force raises the heel of the bead portion, so that the friction force between the bead bottom and the bead seat, which is the bead portion holding force, becomes small. As a result, the bead moves the tapered bead seat inward in the axial direction,
With this movement, the tension of the bead core also decreases, so that the bead holding force suddenly disappears, and the bead falls into the well. To solve this problem, use a rim without a well, or use a rim that forms a protrusion (hump) at the part that comes into contact with the bead toe to prevent the bead from moving inward in the axial direction. An assembly with a tire rim in which a protrusion (hump) is provided and an annular groove for fitting the protrusion (hump) is formed in the bottom of the bead of the tire (Japanese Patent Laid-Open No. 49-13802) has been proposed.

[Problems to be solved by the invention]

However, this technique has a problem in mounting and removing the tire by forming a projection on the bead seat, and when a sudden lateral force is applied when the internal pressure is reduced, the bead holding effect is not sufficient.

SUMMARY OF THE INVENTION An object of the present invention is to provide a wheel rim and an assembly of the wheel rim and the tire that can effectively maintain the function of holding the tire bead portion when the tire internal pressure decreases.

[Means for solving the problem]

The present invention provides an assembly including a tubeless tire having a pair of bead portions and a wheel rim having a well for tire attachment, wherein at least one bead portion of the tire has a bead base portion in a meridional section of the tire, A bead base M at the base of the bead, which is seated on the bead seat (5) of the wheel rim, and a non-extensible bead core (12);
Protruding toe portion (1) located radially inward of the tire and extending radially inward from the bead surface M.
3) and the toe portion (13) and the straight bead surface M
Between the heel end and the toe portion with respect to the distance W4 from the heel end to the center of the bead core. The distance W6 to the inner end N1 in the direction is 2.5 to 3.5 times the distance W4, and the hump groove (1
The distance W5 to 4) is set in a range of 2.1 to 2.5 times the distance W4, while the wheel rim is connected to the toe portion (1).
An assembly of a wheel rim and a tire, wherein an annular groove (3) for receiving the tip of (3) is formed.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

FIG. 1 is a partial sectional view of an assembly of a wheel rim 10 and a tire 11 according to the present invention. In the figure, the bead of the tire 11 has a non-extensible bead core 12 and a toe portion 13 extending axially inside and radially inward of the bead core 12. Since the toe portion 13 fits with the annular groove 3 of the wheel rim 10, the shape and size of the toe portion 13 need to be formed corresponding to the annular groove 3, respectively. Although not shown, a bead apex, a bead reinforcing layer, and a chafer can be applied to the bead portion in the same manner as the conventional tire according to the intended use, and the rubber of the toe portion 13 is a relatively hard rubber such as JISA hardness. In the range of 70 to 85 ° is preferable.

Also, the bead core 12 is characterized by being located axially outward from the conventional tire. For example, the distance W4 from the heel end J to the center of the bead core 12 in the tire axial direction from the heel end J to the toe portion 13 The distance W6 to the end N1 is the distance
It is formed in a range of 2.5 to 3.5 times, preferably 2.9 to 3.2 times of W4. In a conventional tire, the above value is at most about 2.2 times. By increasing this value as in the present invention, the bead core 12 can be brought closer to the rim flange 6 and the fitting with the wheel rim 10 can be more firmly held. sell.
The bead base portion of the bead portion is provided with the toe portion 13 at the tire axial direction, that is, at the inner end in the axial direction as described above, and is provided with a bead surface M which is straight from the heel end J and extends in a meridional section of the tire. . The bead surface M is seated on the bead seat 5 of the wheel rim 10. The heel end J is defined as an intersection T on the extension of each of the bead outer surface Q and the bead surface M at the bead base. Next, the radial end N2 of the toe portion 13 needs to project radially inward from the bead surface M at the base of the bead, and the amount of projection L is arbitrary depending on the application and size of the applied tire. Can be selected.

Further, in the bead base portion of the tire of the present invention, a lower open groove extending between the toe portion 13 and the bead surface M in the tire circumferential direction and recessed radially outward from the bead surface M is formed. The hump groove 14 is formed. In this case hump 4
It is suitable for fitting with a wheel rim formed with. But hump groove 14
The tire formed with the above can be similarly applied to a wheel rim without the hump 4. The hump groove 14, the heel end J of the hump 4
The distances W2 and W5 are the same and are set in a range of 2.1 to 2.5 times the distance W4 from the heel end J to the center of the bead core 12.

FIG. 2 is a partial sectional view of a wheel rim used in the present invention. In the figure, the wheel rim 10 has a well 2 for mounting a tire, and an annular groove 3 extending in the tire circumferential direction is formed adjacent to the well 2 in the axial direction outside, and
A bead seat 5 and a rim flange 6 are formed outside the annular groove 3 in the axial direction. Here, the height h of the inner projection 7 formed inside the annular groove 3 from the bead seat 5 is preferably 5 mm or less, and the depth D of the annular groove 3 from the bead seat 5 is preferably 10 mm or less. . In FIG. 2, the inner projection 7 located inside the annular groove 3 in the axial direction projects outside the bead seat 5, but is provided so as to be located inside the step K in reverse as shown in FIG. This facilitates the mounting of the tire bead portion.
The bead seat 5 can be formed in a tapered shape having a constant angle (α) with respect to the axial direction M as shown in FIG. In the present invention, it is necessary that the groove bottom 3e of the annular groove is located radially inward of the bead seat 5.

FIG. 5 is a cross-sectional view of the assembly of the present invention, in which the above-mentioned special structure is employed in the bead portions on both sides. However, it goes without saying that the above-mentioned special structure can be adopted only in one bead portion. The present invention is a passenger car, a motorcycle, a tricycle,
It can be applied to various vehicles such as ATV, truck and bus.

〔The invention's effect〕

As described above, the wheel rim and tire assembly of the present invention is provided with an annular groove to be fitted with the toe portion, and the distance W6 from the heel end to the tire axial inner end of the toe portion is measured from the heel end to the center of the bead core. Because it is 2.5 to 3.5 times the distance W4,
The position of the bead core will be much closer to the rim flange side, and when the internal pressure decreases, the bead holding function can be further enhanced even if lateral force acts, and the distance W5 from the heel end to the hump groove, Since the distance is set to 2.1 to 2.5 times the distance W4, the ratio of the distance W5 to the distance W6 is specified via the distance W4, and the axial length of the bead surface and the toe portion can be appropriately regulated, and the distance between the wheel rim and the wheel rim can be appropriately controlled. The fitting property can be improved.

[Brief description of the drawings]

1 is a partial sectional view of the assembly of the present invention, FIGS. 2 to 4 are partial sectional views of a wheel rim used in the present invention, and FIG. 5 is a sectional view of the assembly of the present invention. 2 ... well, 3 ... annular groove, 4 ... hump, 10 ... wheel rim, 11 ... tire, 12 ... bead core, 13 ... toe portion, 14 ... hump groove.

Claims (1)

(57) [Claims] 1. An assembly comprising a tubeless tire having a pair of bead portions and a wheel rim having a tire mounting well, wherein at least one bead portion of the tire has a bead base portion in a tire meridional section. The bead surface M of the base of the bead, which is seated on the bead seat (5) of the wheel rim and is linear, is located on the axially inner side of the tire of the non-extensible bead core (12) and is higher than the bead surface M. A protruding toe portion (13) extending inward in the radial direction, and a lower open groove located between the toe portion (13) and the linear bead surface M and recessed radially outward from the bead surface M The distance W6 from the heel end to the inner end N1 of the toe portion in the tire axial direction with respect to the distance W4 from the heel end to the center of the bead core is 2.5 to 3.5 times the distance W4. The distance W5 from the end to the hump groove (14) is set in a range of 2.1 to 2.5 times the distance W4, while the wheel rim receives the tip of the toe portion (13) in the annular groove (3). An assembly of a wheel rim and a tire, wherein a tire is formed.