Tube tire

Abstract: To provide a tube tire which can avoid damage to a tube in charging a sealant, and can prevent the sealant from plugging an air valve of the tube. A first tube half 4i and a second tube half 4o having the same side and circular cross sections are joined together in the condition of raw rubber, and next vulcanized, thereby forming a tube 2 consisting of the two tube halves 4i and 4o integrated in a seamless condition. An air chamber 3 is defined in the first tube half 4i, and a sealant chamber 7 filled with a sealant 8 is defined in the second tube half 4o. When the tube 2 is pierced, the sealant 8 repairs a pierced hole to prevent the puncture. Further, the air chamber 3 is separated from the sealant chamber 7, so that an air valve 6 provided on the air chamber 3 is not plugged with the sealant 8.

Description: The present invention relates to a process for manufacturing a tube tire adapted to be mounted on an outer circumference of a rim, and a tube accommodated in a space adapted to be defined by the rim and the tire, and a tube tire manufactured by such a process. In the case that a tube of a general tube tire is pierced by a nail or the like, the air in the tube passes from a pierced hole of the tube through a fine gap between the tire and the tube to a nipple hole of a rim, and leaks from the nipple hole to the outside, thus readily becoming a so-called punctured condition. It is known to preliminarily inject into a tube a proper amount of liquid sealant for automatically temporarily repairing a pierced hole opened through the tube (see Japanese Patent Laid-open No. 58-74342). However, in the above conventional tube tire, a capsule filled with the sealant is preliminarily put in the tube in forming the tube, and the capsule is broken to charge the sealant into the tube after forming the tube. Accordingly, the tube is apt to be damaged in applying an external force to the capsule to break it. Further, in some case, the sealant may plug an air valve of the tube or may plug a pressure gauge in measuring an air pressure in the tube. DE 200 672 C shows a double-tube arrangement for a tire. An air tube is surrounded by a second tube containing a sealing mass. The second tube is simply disposed at the circumference of the air tube, but not connected thereto. The sealing mass is a viscous fluid containing feathers of a bird. If the tire is pierced, the feathers are pressed into the pierced hole so that the hole is blocked. FR 2 102 954 A shows a self-sealing protecting inlay e.g. for tires. The inlay comprises a mass of water-wetted cotton sealed between outer layers and can be mounted between the outer skin of a tire and the thread of this tire. A hole penetrating one of the skins is blocked by swelling cotton fibers. Document US-A-3 186 468 shows an instant puncture sealing cover or jacket for a tire; the sealing cover comprises several layers and is secured circumferentially to the outer surface of a tube by an appropriate cement layer. To achieve a reliable sealing in case of a puncture, no air should be contained within the sealant chamber. It is accordingly an object of the present invention to provide a process for manufacturing a tube tire having a sealant contained in a sealant chamber, which process prevents the inclusion of air inside the sealant chamber. According to the invention as defined in claim 1, there is provided a process for manufacturing a tube tire including a tire adapted to be mounted on an outer circumference of a rim, and a tube accommodated in a space adapted to be defined by said rim and said tire; the process comprising forming said tube by joining a first tube half and a second tube half each having a circular cross section in a condition of raw rubber at substantially a half of an outer circumferential surface of each, and next vulcanizing said first and second tube halves joined together, such that an air chamber adapted to be filled with air being defined in said first tube half located radially inside of said tire, and a sealant chamber adapted to be filled with a sealant being defined in said second tube half located radially outside of the said air chamber, wherein in the joining step, the first tube half material and the second tube half material are overlaid each other and pressed to be flattened, and wherein prior to charging the sealant, air is supplied from an air valve into the air chamber to expand it, thereby completely expelling the air out of the sealant chamber. By supplying air into the air chamber prior to charging the sealant, air is completely expelled out of the sealant chamber, so that the finished tube tire includes no air within the sealant chamber. In case of a puncture, the sealant will show its full sealing performance. The invention provides further a tube tire as defined in claim 5 manufactured by the process of the invention. The sealant chamber filled with the sealant is provided radially outside of the air chamber. Accordingly, even when the tube is pierced by a nail or the like, a puncture can be quickly repaired by the sealant to thereby prevent leakage of the air from the air chamber. Further, since it is unnecessary to break a capsule in the tube, there is no possibility that the tube may be damaged upon breakage of the capsule. Further, when a radial load is applied to the tire, the tube pressed against the rim through the tire becomes four layers, thereby improving the strength of the tube to prevent damage to a rim striking portion of the tube. Further, the first tube half and the second tube half are joined together in the condition of raw rubber, and thereafter vulcanized. Accordingly, the two tube halves can be completely integrated in a seamless condition. Further, the tube is simple in structure obtained by joining the first tube half and the second tube half each having a simple circular cross section, and charging the sealant into the sealant chamber defined in the second tube half. Accordingly, no increases in weight and manufacturing cost are invited. According to the invention as defined in claim 2 including the limitation of claim 1, said first tube half and said second tube half have the same diameter in their free condition. According to the invention as defined in claim 2, the first tube half and the second tube half have the same diameter in their free condition. Accordingly, the two tube halves can be easily manufactured and joined. In addition, the sealant chamber in the tube completed can be extended to the opposite side walls of the tire. A preferred embodiment of the present invention will now be described with reference to the attached drawings. FIG. 1 is a transverse sectional view of a wheel having a tube tire. FIG. 2 is an illustration of a manufacturing process for a tube. FIG. 3 is a perspective view showing a joined condition of the outer circumferential surfaces of two tube half materials. FIG. 4 is a plan view showing a joining condition of the opposite ends of the two tube half materials. FIG. 5 is a cross section taken along the line 5-5 in FIG. 4. FIG. 6 is a sectional view showing the operation when the tire runs onto an obstacle. As shown in FIG. 1, a rim R of a wheel for a motorcycle is connected through a plurality of wire spokes S to a hub (not shown). A tube tire T consisting of a tire 1 and a tube 2 accommodated in the tire 1 is mounted on the rim R. The tube 2 is composed of a first tube half 4i having a substantially circular shape in cross section and a second tube half 4o having a substantially arcuate shape (circular shape in its free condition) in cross section. The first tube half 4o is located on the radially inside of the tire 1, and the second tube half 4i is located on the radially inside of the first tube half 40. The outer surfaces of the first and second tube halves 4i and 4o are joined together at their substantially half circumferences. Air is charged in an air chamber 3 defined inside the first tube half 4i, and a known liquid sealant 8 is charged in a sealant chamber 7 defined inside the second tube half 4o. An air valve 6 for charging air into the air chamber 3 is provided at a radially inside portion of the first tube half 4i. The rim R is provided with an annular rim body portion 11 extending in the circumferential direction of the tube tire T and a pair of flange portions 12 extending radially outward from the axial opposite ends of the rim body portion 11 to retain the inner circumference of the tire 1. The air valve 6 provided on the tube 2 to charge air into the air chamber 3 is passed through an air valve mounting portion 13 formed at one circumferential position of the rim body portion 11, and is fixed to the air valve mounting portion 13 by nuts 14 and 15. The sealant chamber 7 of the tube 2 is maintained to have a shape along the inner surface of the tire 1 by the air pressure in the air chamber 3. Accordingly, even when a centrifugal force due to rotation of the wheel is applied to the sealant 8 charged in the sealant chamber 7, the sealant 8 can be prevented from being deflected to the outer circumferential side of the tube 2. Accordingly, in the event that the tube 2 is pierced by a nail or the like, a puncture can be quickly filled up with the sealant 8 and repaired to thereby retard leakage of the air from the air chamber 3. Further, the sealant 8 is encapsulated in the sealant chamber 7, and does not flow out to the air chamber 3. Therefore, there is no possibility that the sealant 8 may plug the air valve 6 and a pressure gauge or the like attached to the air valve 6. When the tube tire T runs onto an obstacle 20 on a road surface to receive an impact load as shown in FIG. 6, the tire 1 and the tube 2 are partially compressed in their racial direction by this load. At this time, the tire 1 and the tube 2 are nipped between the radially outward projecting flange portions 12 of the rim R and the obstacle 20, so that the opposed inner wall surfaces of the tube 2 come into contact with each other. However, the wall thickness of the tube 2 pressed by the tire 1 is increased by the first tube half 4i having become two layers and the second tube half 4o also having become two layers, thereby improving the strength of the tube 2. Accordingly, a damage to the tube 2 due to striking of the rim thereagainst can be effectively prevented. Furthermore, since the sealant 8 is charged in the sealant chamber 7, a shock absorbing effect is exhibited by movement of the sealant 8 upward of the tube 2 due to compression of the sealant chamber 7 in the vicinity of an obstacle contact portion of the tire 1. Accordingly, the damage to the tube 2 due to the rim striking can be more effectively prevented. Further, even if the tube 2 is damaged by the rim striking, the damage to the tube 2 can be repaired by the sealant 8 charged in the sealant chamber 7, thereby preventing leakage of the air from the air chamber 3. A manufacturing method for the tube 2 will now be described. As shown in FIG. 2, the manufacturing process for the tube 2 is composed of a material kneading step, tube material extruding step, cutting step, hole forming step, air valve mounting step, joining step, first vulcanizing step, sealant charging step, raw rubber sheet attaching step, second vulcanizing step, and inspecting step. First, a kneaded material obtained in the material kneading step is extruded in the tube material extruding step to thereby obtain a sectionally circular tube material 4m of raw rubber. In the next cutting step, the tube material 4m is cut into pieces each having a given length to thereby obtain a first tube half material 4i' and a second tube half material 4o' of the same size. In the next hole forming step, an air valve mounting hole 41 is formed through the first tube half material 4i', and a sealant charging hole 4 2 is formed through the second tube half material 4o'. In the next air valve mounting step, the air valve 6 is mounted into the air valve mounting hole 4 1 . In the next joining step, the first tube half material 4i' and the second tube half material 4o' are overlaid each other and pressed to be flattened as shown in FIG. 3. The opposite end portions of the first and second tube half materials 4i' and 4o' are next clamped by clamps 16 1 and 16 2 of splicers 16 to join the opposite end surfaces of the two half materials 4i' and 4o'. Since the first and second tube half materials 4i' and 4o' have the same diameter and the same length, the fabrication and joining operations therefor can be easily carried out. While the opposite end surfaces of the first and second tube half materials 4i' and 4o' are simultaneously joined together in this preferred embodiment, the joining of the opposite end surfaces of the first tube half material 4i' and the joining of the opposite end surfaces of the second tube half material 4o' may be separately carried out. In the next first vulcanizing step, the first and second tube half materials 4i' and 4o' joined together are inserted into a heating mold, and heated air or high-temperature steam is supplied from the air valve 6 into the air chamber 3 in the first tube half material 4i', thereby making the half circumference of the first tube half material 4i' and the half circumference of the second tube half material 4o' into close contact with the heating mold, and making the remaining half circumferences of the two tube half materials 4i' and 4o' into close contact with each other. In this condition, the heating mold is heated to carry out vulcanization. That is, in the hold forming step, the sealant charging hole 4 2 is formed through the second tube half material 4o'. Accordingly, when the first tube half material 4i' is expanded by the heated air or high-temperature steam supplied, air is expelled from the inside of the second tube half material 4o' pressed by the first tube half material 4i' through the sealant charging hole 4 2 . As a result, the first and second tube half materials 4i' and 4o' come to close contact with each other, and are vulcanized in this condition. In this manner, the first tube half material 4i' and the second tube half material 4o' are joined and vulcanized in the condition of raw rubber to thereby improve the strength of the tube 2 obtained by completely integrating the two tube half materials 4i' and 4o'. In the next sealant charging step, the sealant 8 is charged from the sealant charging hole 4 2 into the sealant chamber 7 in the second tube half material 4o'. Prior to charging the sealant 8, air is supplied from the air valve 6 into the air chamber 3 to expand it, thereby completely expelling the air out of the sealant chamber 7. In this condition, the charging of the sealant 8 is started. By thus starting the charging of the sealant 8 in the condition that the air in the sealant chamber 7 has been completely expelled, mixing of air with the sealant 8 can be effectively prevented, and only the sealant 8 can be charged. Further, since air is supplied into the air chamber 3 by utilizing the air valve 6, it is unnecessary to form an air charging hole through the first tube half material 4i'. In the next raw rubber sheet attaching step, a raw rubber sheet 19 is attached so as to cover the sealant charging hole 4 2 , and in the next second vulcanizing step, the raw rubber sheet 19 is locally vulcanized in the vicinity thereof to close the sealant charging hole 4 2 , thus completely the tube 2. Since the raw rubber sheet 19 of the same material as that of the tube 2 is used to close the sealant charging hole 4 2 , the strength of the closed portion can be improved to thereby effectively prevent leakage of the sealant 8. In the final inspecting step, the completed tube 2 is inspected to end the manufacturing process. The first tube half material 4i' and the second tube half material 4o' have the same side, so that the sealant chamber 7 can be formed over substantially the half of the circumference of the completed tube 2 as viewed in transverse section. Accordingly, even when any portion of the tread of the tire 1 is pierced by a nail or the like, the puncture can be prevented. If the second tube half material 4o' is smaller in diameter than the first tube half material 4i', the sealant chamber 7 becomes small, so that when a side portion of the tire 1 is pierced, the puncture cannot be prevented. On the contrary, if the second tube half material 4o' is larger in diameter than the first tube half material 4i', the opposite side portions of the sealant chamber 7 project from the air chamber 3, so that the transverse sectional shape of the tube 2 as a whole becomes noncircular. The invention provides a tube tire which can avoid damage to a tube in charging a sealant, and can prevent the sealant from plugging an air valve of the tube. A first tube half 4i and a second tube half 4o having the same side and circular cross sections are joined together in the condition of raw rubber, and next vulcanized, thereby forming a tube 2 consisting of the two tube halves 4i and 4o integrated in a seamless condition. An air chamber 3 is defined in the first tube half 4i, and a sealant chamber 7 filled with a sealant 8 is defined in the second tube half 4o. When the tube 2 is pierced, the sealant 8 repairs a pierced hole to prevent the puncture. Further, the air chamber 3 is separated from the sealant chamber 7, so that an air valve 6 provided on the air chamber 3 is not plugged with the sealant 8.

Claims: Process for manufacturing a tube tire including a tire (1) adapted to be mounted on an outer circumference of a rim (R), and a tube (2) accommodated in a space adapted to be defined by said rim (R) and said tire (1); the process comprising the steps of forming said tube (2) by joining a first tube half (4i) and a second tube half (4o) each having a circular cross section in a condition of raw rubber at substantially a half of an outer circumferential surface of each, and next vulcanizing said first and second tube halves joined together, such that an air chamber (3) adapted to be filled with air being defined in said first tube half (4i) located radially inside of said tire (1), and a sealant chamber (7) adapted to be filled with a sealant (8) being defined in said second tube half (4o) located radially outside of said air chamber (3), wherein in the joining step, the first tube half material (4i') and the second tube half material (40') are overlaid each other and pressed to be flattened, and wherein prior to charging the sealant (8), air is supplied from an air valve (6) into the air chamber (3) to expand it, thereby completely expelling the air out of the sealant chamber (7). A process according to claim 1, wherein said first tube half (4i) and said second tube half (4o) have the same diameter in their free condition. A process according to claim 1 or 2, wherein, after filling the sealant chamber (7) with sealant through a sealant charging hole (4 2 ), said sealing charging hole (4 2 ) is closed by a raw rubber sheet (19) vulcanized in the vicinity of said sealant charging hole (4 2 ). A process according to one of the preceding claims, wherein the completed tube (2) is inspected by a final inspecting step. Tube tire including a tire (1) adapted to be mounted on an outer circumference of a rim (R), and a tube (2) accommodated in a space adapted to be defined by said rim (R) and said tire (1); wherein said tube tire is obtainable by a process comprising the steps of forming said tube (2) by joining a first tube half (4i) and a second tube half (4o) each having a circular cross section in a condition of raw rubber at substantially a half of an outer circumferential surface of each, and next vulcanizing said first and second tube halves joined together, such that an air chamber (3) adapted to be filled with air being defined in said first tube half (4i) located radially inside of said tire (1), and a sealant chamber (7) adapted to be filled with a sealant (8) being defined in said second tube half (4o) located radially outside of said air chamber (3), wherein in the joining step, the first tube half material (4i') and the second tube half material (4o') are overlaid each other and pressed to be flattened, and wherein prior to charging the sealant (8), air is supplied from an air valve (6) into the air chamber (3) to expand it, thereby completely expelling the air out of the sealant chamber (7). A tube tire according to claim 5, wherein said first tube half (4i) and said second tube half (4o) have the same diameter in their free condition. A tube tire according to claim 5 or 6, wherein, after filling the sealant chamber (7) with sealant through a sealant charging hole (4 2 ), said sealing charging hole (4 2 ) has been closed by a raw rubber sheet (19) vulcanized in the vicinity of said sealant charging hole (4 2 ).

Inventors: NAKAYAMA KENGO, TAKAHASHI HIROHISA, YAMAGIWA TOSHIO, YAMAZAKI KATSUTOSHI, NAKAYAMA, KENGO, TAKAHASHI, HIROHISA, YAMAGIWA, TOSHIO, YAMAZAKI, KATSUTOSHI
Applicants: HONDA MOTOR CO LTD, HONDA GIKEN KOGYO KABUSHIKI KAISHA
Application year: 1997
Main classification: B60C17
IPC codes: B29L23, B29C73, B60C5, B60C19, B29L30