JPH03231008A - Assembly of tire and rim for bicycle - Google Patents

Abstract

PURPOSE:To prevent the occurrence of a puncture without damaging drive stability and a riding feeling by disposing a cushioning body, having a specified crows-sectional area, peripheral length, and cross sectional length, between a tire and a tube disposed in a cavity surrounded with the tire and a rim. CONSTITUTION:An assembly 1 comprises a tire 2, a rim 3 with which the tire 2 is rimmed, a tube 5 disposed in a cavity 4 surrounded with the tire 2 and the rim 3, and a cushioning body 6 located between the tire 2 and the tube 5. In the cushioning body 6, a ratio Aa/Ba between a cross sectional area Aa thereof and an area Ba of the tube 5 is set to 3/7-1.5. A ratio Ab/Cb between a peripheral length Ab of the cushioning body 6 and a peripheral length Cb of the tire 2 is set to 0.6-1.0. A ratio Ac/Cc between a cross-sectional length Ac of the cushioning body 6 and a crosssectional length Cc of the tire 2 is set to 0.8-0.9.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a tire and rim assembly for a two-wheeled vehicle that can prevent the occurrence of banking without impairing running performance.

[Conventional technology]

In motorcycles that travel off-road, the condition of the road surface and driving conditions are different from those in off-road travel, so that punctures occur more frequently than in motorcycles that travel only off-road. Particularly when the tire is driven over gravel, rubble, or rock, there is a high risk that the outer skin of the tire will be locally deformed and the tube will be repeatedly deformed locally, causing a bank. Furthermore, during a motocross race, the tire often deforms locally when landing after a jump, compressing the tube and damaging it.

[Problem to be solved by the invention]

For motorcycle tires that run on such uneven terrain, it is necessary to increase the internal tube pressure, use thick-walled tubes, use double tubes, use special materials such as mousse for the tubes, etc. However, even with such specifications, it has not been possible to eliminate flat tires, and with the above specifications, steering stability and riding comfort are significantly reduced.

Therefore, drivers who drive on rough terrain have been looking forward to the emergence of tires that have less risk of bank formation and that maintain handling stability and ride comfort.

The inventor discovered that by interposing a cushioning material between the tire and the tube, the air inside the tube can maintain steering stability and riding comfort, and the cushioning material can prevent the propagation of impact force to the tube. They discovered a scale that prevents punctures.

The present invention provides a tire and rim assembly for a two-wheeled vehicle, which is based on the provision of a cushioning material between the tire and the tube, and is capable of preventing tire banking while maintaining handling stability and riding comfort. The purpose is

[Means to solve the problem]

The present invention provides a tire, a rim for assembling the tire, a tube disposed in a bore surrounded by the tire and the rim, and a tube disposed between the tire and the tube and extending from the tire equator in a cross section including the tire axis. A tire and rim assembly for a two-wheeled vehicle comprising an annular shock absorber made of a sponge material that extends on both sides and terminates near the tire bead, and has a thinner wall at the end than at the tire's equator. .

Further, the buffer has a ratio A a of the area (Aa) of the buffer in a cross section of the buffer in a pressurized state of the tube to the area (Ba) of the tube surrounded by the outer peripheral surface of the tube in the cross section. /B a is preferably 3/7 or more and 1.5 or less.

Furthermore, the buffer body, in its natural state without being pressurized,
A circumference (Ab) of the buffer passing through the tire equator of the buffer;
The circumference of the tire passing through the tire equator on the inner peripheral surface of the tire (Cb
) is 0.6 or more and 1.0 or less, and the cross-sectional length (Ac ) and the cross-sectional length (Cc) of the tire from one bead end to the other bead end from the tire equator to the other bead end of the inner periphery of the cross-sectional area A c / Cc is 0.8 or more and 0.
．． It is preferable to set it to 9 or less.

Further, it is preferable that the buffer has closed cells and a foaming ratio of 4 or more and 15 or less.

[Effect]

Since a shock absorber made of a sponge material is provided between the tire and the tube, the risk of banking can be reduced without significantly impairing steering stability and riding comfort.

In addition, the buffer body has a thinner wall at the end near the bead than at the equator, so near the equator, where a large impact is applied to the tube, the buffer efficiently absorbs the impact and prevents punctures. In the bead portion, which bends and deforms when an impact force is applied and relieves the impact force, the thin buffer body maintains the bending deformation of the bead portion, reducing steering stability and riding comfort. can be prevented.

Furthermore, when the ratio between the area Aa of the buffer body and the area Ba of the tube is regulated, the steering stability and riding comfort are further stabilized, and the puncture resistance is also improved.

Furthermore, the circumferential length ratio A of the buffer body and tire in a natural state
b/Cb, and the cross-sectional length ratio of the buffer body and tire AC/C
When each of C is regulated, the shape and amount of bubbles of the cushioning body are stabilized when the tire is pressurized, and it becomes easy to ensure steering stability and ride comfort.

Furthermore, when the bubble ratio of the shock absorber is regulated, it becomes easier to maintain the above-mentioned steering stability and riding comfort, and furthermore, the puncture resistance is further improved.

〔Example〕

An embodiment of the present invention will be described below based on the drawings.

In the figure, a tire and rim assembly 1 for a two-wheeled vehicle according to the present invention
A tire 2, a rim 3 for assembling the tire, and a tube 5 disposed in a bore 4 surrounded by the tire 2 and rim 3.
and a buffer body 6 disposed between the tire 2 and the tube 5.

The tire 1 includes a tread portion 12 having a trend pattern formed on its outer peripheral surface, a sidewall portion 13.13 extending radially inward from both ends of the tread portion 12, and a radially inner end side of the sidewall portion 13.13. It has a hollow toroidal shape with a pair of bead parts 5.15 located respectively.

The rim 3 has a ring shape connecting a pair of bead seat parts 17.17 on which bead bottom surfaces 16.16 formed at the radially inner ends of the bead parts 15.15 are respectively seated,
The inner cavity 4 is formed by the tire 2 and the rim 3, and the tube 5 that can apply internal pressure to the tire 2 is arranged in the inner cavity 4.

The buffer body 6 is made of a sponge material with closed cells interposed therein,
Each of the sponge materials having compositions A to E can be formed by blending and producing a plurality of raw materials as shown in Table 1, for example.

In this example, the foaming ratio of the sponge material with each of the above compositions is set to be 4 or more and 15 or less. If it is less than 4, the cushioning properties are lowered and the shock absorbing power is weakened, so that the shock acting on the tire is propagated to the tube 5 without being attenuated, resulting in a decrease in the puncture resistance of the tube 5. On the other hand, if it is 15 or more, the buffer body 6 becomes flexible and becomes thinner due to the internal pressure applied to the tube 5, and as a result, the shock absorbing ability also decreases.

The buffer body 6 has a surface facing the inner circumferential surface 21 of the tire 2, that is, an outer surface 2.
2 extends from the tire equator C to both sides and the bead part 1 of the tire 2
It terminates in the 5 neighborhood.

In this example, the cushioning body 6 is shown in the cross section in the tire axial direction of the cushioning body 6 in a pressurized state where a pressure equal to the normal internal pressure of the tire 2 is applied inside the tube 5, that is, in a cross section.
The area Aa of the tube and the outer circumferential surface 19 of the tube in the cross section
The ratio A a /B a to the area Ba surrounded by is set to be 3/7 or more and 1.5 or less.

If the ratio Aa/Ba is less than 3/7, the shock absorbing power of the shock absorber 6 will be reduced and the effect of preventing punctures will be small, and if it exceeds 1.5, the steering stability will be reduced.

Furthermore, the thickness of the buffer body 6 is made thinner at the end F portion than at the tire equator C portion. Note that the thickness of the buffer body 6 may be formed so as to gradually decrease from the tire equator C toward the end portion F, or may be made uniform in the range of the tread portion 12 including the tire equator C, and the thickness of the tread portion 12
The thickness may be gradually reduced from the end toward the sidewall portion 13 and bead portion 15.

In addition, in the natural state where the buffer body 6 is not pressurized, the ratio A of the circumference Ab of the buffer body 6 passing through the tire equator C and the circumference cb of the tire inner peripheral surface 21 passing through the tire equator.
It is preferable that b/Cb is 0.6 or more and 1.0 or less.

If the ratio A b / Cb is less than 0.6, even when the tube is pressurized, the inner circumferential surface 21 of the tire 2 and the outer circumferential surface 23 of the buffer body 6 will come into contact near the tire equator C. Therefore, there may be cases where no internal pressure acts on the tire 2. On the other hand, if the ratio Ab/cb exceeds 1.0, there will be a gap between the shock absorber 6 and the tire 2 even when the shock absorber 6 is fitted into the tire 2, and the shock absorber 6 will be compressed near the tire equator C. As a result of the decrease in voids, the expected performance of the buffer body 6 may not be obtained. Furthermore, when inserting the buffer body 6 into the inner cavity 4 of the tire 2, there is a possibility that the buffer body 6 may not be inserted into the tire 2 in a homogeneous state, such as wrinkles occurring in the buffer body 6.

Further, the buffer body 6 has a cross-sectional length AC from its terminal end F to the tire equator C to the other terminal end F′ at the outer periphery 23 of the cross section in the natural state where no pressure is applied as described above; The ratio Ac/Cc of the cross section of the tire 2 from one bead end E to the other bead end E'' via the tire equator C is set to be 0.8 or more and 0.9 or less. It is desirable to do so. Note that the buffer body 6 is compressed by applying internal pressure to the tube 5, and the ratio A c / C c 7! ! (If it exceeds 0.9, the terminal end F will extend beyond the bead end E during pressurization, and as a result, the buffer body 6 will be compressed in the transverse length direction, resulting in non-uniformity. Also, the tube 5 There is a risk of local deformation of the tube 5 due to the formation of wrinkles on the inner surface facing toward the tire 2.If the ratio Ac/Cc becomes 0.8 or less, the tire 2 and the tube may be damaged from the bead portion 15 to a part of the sidewall portion 13. As a result of the direct contact between the two parts, when the traveling frame is subjected to the largest bending deformation, the shock absorber 6 is placed near the connecting part between the door part 15 and the side wall part 13.
It means that it does not exist. Therefore, there is a risk that the tube 5 may be pinched by the tire 2 due to repeated deformation of the tire 2, resulting in local deformation that may cause a bank.

〔Example〕

Tire size 80/100-21 for the front wheel of a motorcycle
tires, and tire size 110/90 for the rear wheels.
-19 tires each having the configuration shown in Figure 1 and having the configuration shown in Figure 1.2.
We manufactured a prototype with the specifications shown in the table and tested its performance. For comparison, we also prototyped a tire with a conventional structure without a buffer and tested its performance.

The test was conducted and judged under the following conditions.

The front and rear wheels of a motocross motorcycle were equipped with tires of the same specifications, and the vehicle was run on a motocross course with a lot of gravel and rock.

B) Driving performance Handling performance, straight-line stability, turning stability, shock absorption and ride comfort were judged based on the driver's feeling and evaluated using a five-step method. The larger the numerical value, the better, and 2°5 or more is a pass.

(Example) Durability The above-mentioned course was continuously run for 2 hours and the occurrence of punctures was investigated. The test was repeated three times under the same conditions.

As a result of the test, the tires of the example were able to prevent punctures, and no significant deterioration in running performance was observed in the tires of the example.

〔Effect of the invention〕

As mentioned above, the main feature of the motorcycle tire and rim assembly of the present invention is to provide a cushioning body made of sponge material between the tire and the tube, so that it can be achieved without impairing handling stability and riding comfort. It can prevent punctures.

[Brief explanation of drawings]

FIG. 1 is a sectional view showing one embodiment of the present invention. 2-tire, 3- rim, 4-...inner cavity, 5-
Tube, 6-buffer, 15...-bead part, Aa
-・-Area of the buffer body, Ab...-Perimeter of the buffer body, Ac
- Transverse length of buffer body, Ba・′・area of tube, Ca
-... Tire circumference, Cc - - Tire transverse length, E
, E”--bead end, F, F'-- end of buffer.

Claims (1)

[Scope of Claims] 1. A tire, a rim for assembling the tire, a tube disposed in a bore surrounded by the tire and the rim, and a cross section disposed between the tire and the tube and including the tire shaft. A tire and rim combination for a two-wheeled vehicle comprising an annular shock absorber made of a sponge material that extends from the tire equator to both sides and terminates near the tire bead, the end portion being thinner than the tire equator. Three-dimensional. 2 The buffer has a ratio Aa/Ba of the area (Aa) of the buffer in a cross section of the buffer in a pressurized state of the tube and the area (Ba) of the tube surrounded by the outer peripheral surface of the tube in the cross section. The tire and rim assembly for a two-wheeled vehicle according to claim 1, wherein: is 3/7 or more and 1.5 or less. 3 In the natural state where the buffer is not pressurized, the buffer has a circumference (Ab) of the buffer that passes through the tire equator, and a circumference (Cb) of the inner peripheral surface of the tire that passes through the tire equator.
The ratio Ab/Cb is 0.6 or more and 1.0 or less,
Moreover, at the outer periphery of the cross section of the cushioning material, the cross-sectional length of the cushioning material from the terminal end to the other terminal end via the tire equator (
The ratio Ac/Cc of the cross-sectional inner circumference of the tire from one bead end to the tire equator to the other bead end (Ac) is 0.8 or more and 0.9 The tire and rim assembly for a two-wheeled vehicle according to claim 1 or 2, characterized in that: 4. The tire and rim assembly for a two-wheeled vehicle according to claim 1, 2 or 3, wherein the buffer has closed cells and has an expansion ratio of 4 or more and 15 or less.