JPH05201213A - Assembly of tire and rim for bicycle - Google Patents

Abstract

PURPOSE:To obtain an assembly of a tire and a rim of a bicycle which can prevent puncture without lowering driving performance. CONSTITUTION:This assembly is provided with a tire 2, a rim 3 on which the tire 2 is assembled, a tube 5 arranged in an inner cavity 4 surrounded by the tire 2 and the rim 3, and a buffer 6 made of a rubber composition arranged between the tire 2 and the tube 5 and extending from a tire equator C to both sides on a sectional face including a tire axis and forming a ring with the section of a crescent with the height position of 0.4 to 0.6 times of the tire sectional height Ha from a bead bottom face 16 as its side end.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a tire / rim assembly for a two-wheeled vehicle capable of preventing punctures without impairing running performance.

[0002]

2. Description of the Related Art A motorcycle that travels off-road has a higher frequency of punctures than one that travels only on-road because the condition of the road surface and the traveling conditions differ from those when traveling on-road. . In particular, when running on gravel, rubble, or rock, the tire skin is locally deformed, and there is a high risk of puncture due to repeated local deformation of the tube. Further, in a motocross race, the tire is locally deformed at the time of landing after the jump, so that the tube is often pinched and damaged.

[0003]

In the tire for a motorcycle which travels on such an uneven terrain, it is possible to increase the internal pressure of the tube, use a thick tube, use a double tube, or use a mousse or the like for the tube. Puncture is prevented by using a special material, but even with such specifications, the puncture has not been extinct. Further, with the above-mentioned specifications, steering stability and riding comfort are significantly reduced.

Therefore, it has been expected that tires that are less likely to cause a flat tire and that maintain driving stability and riding comfort will be developed among drivers traveling on rough terrain.

By interposing a cushioning material between the tire and the tube, the inventor can maintain the steering stability and riding comfort by the air in the tube, and the cushioning material prevents the propagation of impact force to the tube. It was found that punctures can be prevented by doing so.

The present invention is based on the fact that a cushioning material is interposed between a tire and a tube, and a tire-rim assembly for a motorcycle capable of preventing flat tires while maintaining steering stability and riding comfort. The purpose is to provide.

[0007]

According to the present invention, there is provided a tire, a rim assembled to a bead portion of the tire, a tube disposed in an inner space surrounded by the tire and the rim, and between the tire and the tube. With a cushioning member made of an annular rubber composition having a crescent-shaped cross section extending from the tire equator to both sides in the meridian direction in a transverse section including the tire shaft, and the cushioning member is in a pressurized state of a tube. The height H from the bottom surface of the bead at both ends is defined as the tire cross-section height Ha, which is the distance from the bottom surface of the bead of the tire to the radially outer end.
It is an assembly of a tire and a rim for a motorcycle that is 4 times or more and 0.6 times or less.

Further, it is preferable that the buffer body has closed cells and the expansion ratio thereof is 4 or more and 15 or less.

[0009]

Since the cushioning body made of solid rubber or sponge material is provided between the tire and the tube, the risk of puncture can be reduced without significantly impairing steering stability and riding comfort.

Further, since the shock absorber has an annular body having a crescent-shaped cross section extending from the equatorial plane to both sides in the tire axial direction, the shock absorber efficiently absorbs the shock in the vicinity of the tire equator where a large shock acts on the tube. In the sidewall part and the bead part that prevent puncture while bending and deforming by applying an impact force to reduce the impact force, the bending of the bead part is caused by the fact that the cushioning body reduces its thickness and is interrupted. The deformation is retained, and the deterioration of driving stability and riding comfort can be prevented.

The height H at the both ends of the buffer is the cross-sectional height H.
If it is less than 0.4 times a, the cushioning body suppresses the bending deformation of the sidewall portion and the bead portion, and as a result, the riding comfort deteriorates. If the height H at both ends exceeds 0.6 times the cross-sectional height Ha, the shock absorbing capacity of the cushioning body will decrease, the risk of puncture will increase, and the side wall portion will be affected by shock. In the buttresses, the bending deformation may be large and the tire may be damaged.

Further, when the bubble ratio of the buffer is regulated, it becomes easy to maintain the steering stability and riding comfort, and the puncture resistance is further improved.

[0013]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings. In the drawings, a tire-rim assembly 1 for a motorcycle according to the present invention includes a tire 2, a rim 3 for assembling the tire, and a tube 5 disposed in an inner cavity 4 surrounded by the tire 2 and the rim 3. A cushion 6 arranged between the tire 2 and the tube 5.
It has

The tire 1 has a tread portion 12 having a tread pattern formed on its outer peripheral surface, and side wall portions 13 and 13 extending from both ends thereof inward in the tire radial direction.
A hollow toroidal shape is formed having a pair of bead portions 15, 15 respectively located on the radially inner end sides of the side wall portions 13, 13.

The rim 3 has a ring shape in which a pair of bead seat portions 17 and 17 on which bead bottom surfaces 16 and 16 formed on the radially inner ends of the bead portions 15 and 15 are respectively seated are connected. The inner cavity 4 is formed by the rim 3 and the rim 3, and the tube 5 capable of applying an inner pressure to the tire 2 is arranged in the inner cavity 4.

The cushioning body 6 forms a crescent-shaped annular body which extends in a lateral cross section including the tire shaft while reducing its thickness from the tire equator C to both sides.

In this embodiment, the buffer body 6 is made of a sponge-like rubber composition having closed cells interposed therein. By mixing and forming a plurality of raw materials as shown in Table 1, each of the compositions A to E is prepared. A sponge material can be formed.

In this embodiment, the expansion ratio of the rubber having each of the above compositions is 4 or more and 15 or less. If it is 4 or less, the cushioning property is deteriorated and the impact absorbing power is weakened, so that the shock acting on the tire is propagated to the tube 5 without being attenuated, and as a result, the puncture resistance of the tube 5 is deteriorated. On the other hand, when it is 15 or more, the shock absorbing body 6 becomes flexible and becomes thin due to the inner cavity pressure applied to the tube 5, so that the shock absorbing ability also decreases.

Further, the buffer body 6 has a bead bottom surface 1 at both side ends F of the buffer body 6 when the tube 2 is under pressure.
The height H from 6 is 0.4 times or more and 0.6 times or less of the tire section height Ha, which is the distance from the bead bottom surface 14 to the bead bottom surface 16 of the tire 2 to the outermost end in the tire radial direction. There is. Therefore, the tire 2 has its tread portion 1
2, and the inner peripheral surface 2 of the buttress of the sidewall portion 13
The cushioning body 6 comes into close contact with the contact member 3.

The cushioning body 6 is provided with a uniform thickness portion having a uniform sectional thickness in the vicinity of the tire equator, and both side ends F, F from the uniform thickness portion.
It can also be formed so that the thickness gradually decreases.

Further, the cushioning body 6 is a case where a long nail is inserted from the tread portion 2 by setting the rubber thickness on the equatorial plane C of the tire within the range of 5 to 15 mm regardless of the tire size. However, the nail can be prevented from penetrating the tube 5.

[0022]

[Example] Tire size 80/1 for front wheels of a motorcycle
For tires 00-21, tire size 1 for rear wheels
Tires of 10 / 90-19 were prototyped according to the specifications shown in Table 1 and Table 2 with the configuration shown in FIG. 1, and the performance was tested. For comparison, a tire having a conventional structure without a cushioning body was prototyped and the performance was also tested.

The test was conducted and judged under the following conditions. The tires of the same specifications were mounted on the front and rear wheels of the motorcycle for motocross, and the motocross course with a lot of gravel and bedrock was run.

(A) Running performance The handling, straight running stability, curving stability, shock absorption and riding comfort were each judged by the driver's feeling and evaluated by the 5-step method. The larger the value, the better, and the value of 2.5 or more is acceptable.

B) Durability The above course was continuously run for 2 hours, and the presence or absence of puncture was investigated. The test was repeated 3 times under the same conditions.

As a result of the test, in the examples, punctures could be prevented, and in the examples, the running performance was not significantly deteriorated.

[0027]

As described above, the tire-rim assembly for a motorcycle according to the present invention is characterized in that a cushioning member made of a rubber composition is provided between the tire and the tube.
A puncture can be prevented without impairing driving stability and riding comfort.

[Brief description of drawings]

FIG. 1 is a sectional view showing an embodiment of the present invention.

[Explanation of symbols]

 2 tire 3 rim 4 lumen 5 tube 6 buffer 15 bead part C tire equator F side end of buffer

[Table 1]

[Table 2]

Claims (2)

[Claims] 1. A tire, a rim assembled to a bead portion of the tire, a tube disposed in an inner space surrounding the tire and the rim, and a cross section disposed between the tire and the tube and including a tire shaft. With a cushioning body made of a ring-shaped rubber composition having a crescent-shaped cross section extending from the tire equator to both sides in the meridian direction, the cushioning body has a height from the bottom surface of the bead at both ends in a pressurized state of the tube. A tire-rim assembly for a two-wheeled vehicle, wherein the height H is 0.4 times or more and 0.6 times or less of a tire cross-sectional height Ha which is a distance from the bead bottom surface of the tire to an outer end in the radial direction. 2. The tire-rim assembly for a motorcycle according to claim 1, wherein the buffer body has closed cells and a foaming ratio thereof is 4 or more and 15 or less.