DESCRIPTION OF THE PRIOR ART A tubeless tire serves to provide an airtightness to the tire itself to thereby allow the tire and a rim to directly maintain an air pressure. The tubeless tire is adhered to by a liner of airtightness-rich rubber to maintain an airtightness therein and to prevent a puncture thereof.

As a prior art of preventing a puncture of a tubeless tire by inserting a separate inside material in the tire, Korean laid-open utility model No. 96-13692 (laid open on May 17,1996) is disclosed. The utility model No. 96-13692 includes, as shown in Figure 1, a tire 4 inserted on a periphery of a rim 2, and the tire 4 is formed at an inner side thereof with an inside material 10 adhered thereto and formed with a multitude of air chambers 6. The inside material 10 consists of a great many spheres of rubbery material, each sphere intermingled therein and having an air chamber 6 therein. An air pressure chamber 12 of a predetermined pressure filled with air is formed between the inside material 10 and the rim 2. The tubeless tire thus constructed does not rapidly leak air due to the inside material 10, even poked by a needle-like substance, to thereby lend a vehicle an assistance in safe operation.

SUMMARY OF THE INVENTION

However, there is a problem in the tubeless tire thus constructed in that the inside material cannot maintain solid stable state. Thus, the inside material is lopsidedly placed, for example, by centrifugal force when a vehicle corners to cause a fear of deforming the inside material, thereby resulting in an unbalance to the tire and trembling to a body of the vehicle and deteriorating a rideability.

There is another problem in that, when a needle-like substance deeply penetrates the tire to touch the inside material, a sphere first touched by the needle-like substance is destroyed, and when one sphere is disrupted, another sphere nearby is pushed into an empty space formed by the destroyed sphere by air pressure, and the sphere thus pushed thereinto is also broken by the needle- like substance, such that these sequential destruction of spheres occur continuously within a short period of time, destroying nearly whole inside material.

There is still another problem in that the inside material is remarkably reduced in volume thereof when spheres in the inside material having a predetermined volume are ruptured in the tire, thereby decreasing air pressure in the tire abruptly to deteriorate obtainment of running stability during puncture of the tire.

There is still further problem in that the air chamber in the inside material is disrupted when the inside material is heated to thereby be expanded, thereby decreasing durability of the inside material.

The present invention is thus provided to solve the aforementioned problems and it is an object of the present invention to provide an inside material of puncture-preventing tire and its manufacturing method by which high-weighted and durability-rich inside material can assuredly prevent leak of air from inside of the tire when a vehicle is flat to thereby guarantee safe running.

It is another object of the present invention to provide an inside material of puncture-preventing tire and its manufacturing method by which stably-

formed inside material is so closely adhered to an inner surface of the tire that its shape is not affected by any external force, thereby preventing a bad rideability, a bad steering stability and a lower fuel consumption due to unbalanced tires.

In accordance with one object of the present invention, there is provided an inside material of a tubeless tire closely adhered to an inner surface thereof for preventing puncture, wherein the inside material comprises a plurality of element members having a plurality of grooves forming airtight chambers, each adhered therebetween to formed a ring.

The element members are either formed in a snap ring shape having both free ends adhered to a rim by being longitudinally cut and having a predetermined thickness in circumferential direction of the tire or formed in ring shapes of different diameters by being horizontally cut and having a predetermined thickness in diametral direction of the tire. The airtight chambers can be filled with air but are preferred to be filled with helium gas.

In accordance with another object of the present invention, there is provided a manufacturing method of an inside material of puncture-preventing tubeless tire, wherein the method of forming the inside material comprises the steps of: forming a plurality of grooves respectively at a plurality of element members of predetermined shapes, mutually combining the plurality of element members within a helium-gassed chamber to form airtight chambers filled with helium gas in the grooves.

It is preferred to combine the element members to form external shape of the inside material and thereafter to coat inner and outer circumferential surfaces thereof with urethane.

BRIEF DESCRIPTION OF THE DRAWINGS

For fuller understanding of the nature and object of the invention, reference should be made to the following detailed description taken in conjunction with the accompanying drawings in which: Figure 1 is a sectional view of a tubeless tire having inside material for puncture prevention according to the prior art; Figure 2 is a longitudinal sectional view of a tubeless tire adhered by inside material at an inner surface thereof according to a first embodiment of the present invention; Figure 3 is a perspective view for illustrating part of element member in Figure 2; Figure 4 is a sectional view taken along line A-A in Figure 3; Figure 5 is a sectional view of element member according to a second embodiment of the present invention; Figure 6 is a sectional view of element member according to a third embodiment of the present invention; Figure 7 is a constitutional diagram of inside material where element members are continuously adhered to form a ring-shaped inside material; Figure 8 is a longitudinal sectional view for illustrating a tubeless tire adhered by inside material at an inner surface thereof according to a fourth embodiment of the present invention; Figure 9 is a perspective view for illustrating part of the element members in Figure 8; Figure 10 is a sectional view taken along line B-B in Figure 9; Figure 11 is a longitudinal sectional view for illustrating a tubeless tire adhered by inside material at an inner surface thereof according to a fifth embodiment of the present invention; Figure 12 is a perspective view for illustrating part of element members in Figure 11; and Figure 13 is a sectional view taken along line C-C in Figure 12.

DETAILED DESCRIPTION OF THE INVENTION

Preferred embodiments of the present invention will now be described in detail with reference to the accompanying drawings.

Figure 2 is a longitudinal view of a tubeless tire adhered by inside material at an inner surface thereof according to a first embodiment of the present invention. As illustrated in Figure 2, a rim 22 comprising a wheel is inserted at a periphery thereof by an opened tip end of a tire 24 and the tire 24 is closely adhered to at an inner peripheral surface thereof by an inside material 26 of a predetermined thickness.

The rim 22 is formed at a tip end thereof with a bent part 28 which is outwardly bent for the tire 24 to be inserted and hitched thereby. The rim 22 is centrally coupled with an air valve 30 through which air can be infused. The rim 22 is coupled at an inner side thereof with a disk, a spoke, a spider and the like which are already well-known as the prior art, and is inserted into an axle.

The tire 24 is made of rubber known in the art and is formed therein with a void opened toward the rim 22.

The inside material 26 is made of urethane material and is formed at walls thereof with a plurality of airtight chambers 32. The inside material 26 is also formed with an air chamber 34 opened toward the rim. Both ends of the inside material are adhered to a bent part 28 of the rim 22 to further maintain an airtightness. Each airtight chamber 32 is filled with helium gas. The helium gas is inert gas which shows no reaction at all at temperature ranges from -40 C to 1, 200°C, such that there is not problem of thermal expansion and light in weight. In other words, the helium gas poses no problem of thermal expansion caused by friction force generated when the tire touches the ground surface, and lightens the tire.

Element members (36,38, 40, ), each separated at a predetermined angle, are coupled along the circumference to thereby form the ring-shaped inside material 26, as illustrated in Figure 3. Each element (36,38, 40, w), is

formed at side thereof with a plurality of grooves (42,44, 46,48) as illustrated in Figure 4, from which the plurality of element members (36,38, 40) are intercoupled at sides thereof in helium-gased chamber of predetermined pressure, thereby forming the inside material 26.

Each element member has a predetermined thickness towards circumferential direction of the tire, longitudinally cut and forms a snap ring shape having free ends at both sides thereof.

The airtight grooves (42,44, 46,48) thus comprise the airtight chamber 32 filled with helium gas, thereby forming a ring-shaped inside material adhereable to an inner surface of the tire, as illustrated in Figure 7. A combined line (L1) of element members is shown in Figure 7.

Meanwhile, the air in the airtight chamber 32 can be filled in by coupling of the plurality of element members in the air chamber of predetermined pressure.

It is preferred to form grooves at the element members, followed by polyurethane coating on the respective element members (36,38, 40, w). This coating expedites coupling of the element members and increases airtightness.

Furthermore, airtightness can be further improved when the element members (36,38, 40,) are coupled to formed an external shape of the inside material 26 and to coat inner and outer peripheral surfaces thereof with polyurethane.

The coupling of each element member is done by adhesives known in the art which retains high adhesiveness even in the high temperature.

As mentioned above, there is an advantage in the inside material of tubeless tire according to the present invention in that the inside material is hardly affected at its shape by external force such as centrifugal force because it is stably adhered to an inner surface of the tire, thereby preventing deterioration of rideability and steering safety due to unbalanced tires. There is another

advantage in that no continuous break-up of the airtight chambers occurs because only an airtight chamber directly touch and poked by needle-like substance is destroyed leaving other airtight chambers nearly intact, such that durability is excellent and safe operation of a vehicle is guaranteed even during a puncture of tires. There is still another advantage in that helium-filled inside material is light in weight because of low specific gravity of helium such that there is no fear of a bad fuel consumption and steering stability of a vehicle.

There is still further advantage in that helium gas is hardly affected by heat, such that durability of the inside material is not deteriorated by heat expansion.

It should be also noted that cylindrical grooves (42', 44', 46', 48') are formed at both sides of the element members to form a plurality of airtight diaphragms as illustrated in Figure 5, or semi-spherical grooves (72,74, 76,78) are formed at both sides of the element members, each groove facing the opposite groove, to form a plurality of airtight chambers, as illustrated in Figure 6.

Figure 8 is a longitudinal sectional view for illustrating inside material adhered to an inner surface of a tubeless tire according to a fourth embodiment of the present invention. Inside material 126 according to the fourth embodiment comprises a plurality of ring-shaped element members (136,138, 140, w) adhered together, as shown in Figure 9.

Each element members has a predetermined thickness toward diametral direction of the tire, horizontally cut and forms ring shapes of respectively different diameters.

The element member having a smallest diameter is adhered to a rim to thereby maintain an airtightness.

As illustrated in Figure 10, a plurality of grooves (142,144, 146,148) are formed at sides of the element members and the plurality of grooves (142, 144,146, 148) at the plurality of element members (136,138, 140, w) are

coupled in helium-gassed chamber of predetermined pressure, each facing therebetween, to thereby produce the inside material. Interior of the grooves (142,144, 146,148) therefore becomes the airtight chamber 32 filled with helium gas. A coupled line thereof (L2) is shown in Figure 8.

Figure 11 is a longitudinal sectional view for illustrating a tubeless tire adhered by inside material according to a fifth embodiment of the present invention, where an airtight chamber 152 formed at inside material 156 is shown as a rectangular void.

As for these kinds of structures shown in Figures 12 and 13, a plurality of element members (166,168, 170, w) are formed at only one side thereof with rectangular grooves (172,174, 176, 178), and the plurality of element members (166, 168, 170,) are coupled in helium-gassed chamber having a predetermined pressure to the airtight chamber 152, thereby producing the inside material. A coupled line thereof (L3) is shown in Figure 11.

In the above, the descriptions were made based on the specific embodiments of the present invention with reference to the attached drawings.

However, it should be understood that the present invention is not to be limited to the specific embodiments, but various changes and modifications can be added without departing from the scope of the present invention as defined in the appended claims.

As apparent from the foregoing, there is an advantage in the puncture- preventing inside material according to the present invention in that the inside material is closely adhered to an inner circumferential surface of the tire, such that, even needle-like substances penetrate deep into the tire, there is no fear of air being leaked from the tire, thereby providing a safe running of a vehicle.

There is another advantage in that durability is excellent and a safe driving is guaranteed even during puncture of tire because there is no fear of the plurality of airtight chambers being continuously destroyed as only an airtight

chamber directly touched and disrupted by needle-like substances is destroyed, leaving other ambient airtight chambers intact.

There is still another advantage in that the inside material is adhered to an inner circumferential surface of the tire in a stable predetermined shape, such that the inside material is hardly changed in its shape even though it is affected by external force such as centrifugal force, thereby causing no fear of deteriorating rideability due to unbalanced tires.

There is still another advantage in that the inside is made of light polyurethane and if respective airtight chambers are filled with helium gas, the inside material becomes lighter in weight, such inside material-inserted tires do not deteriorate fuel consumption nor the running stability of a vehicle. There is still further advantage in that durability of the inside material is not deteriorated due to thermal expansion because the helium gas is hardly affected by the heat expansion.