JPH08437B2 - Tire manufacturing method - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention, when a tire is mounted on a rim, prevents air pockets from being formed between the outer surface of the bead portion and the rim flange of the rim to prevent rim displacement and durability. The present invention relates to a method for manufacturing a tire capable of improving running accuracy and stabilizing the assembling accuracy of a rim assembly and maintaining running stability.

[0002]

2. Description of the Related Art Pneumatic tires, for example, heavy-duty tires used for buses, trucks, etc.
The load is increasing as the load increases, and the rim is fitted with a strong fitting force as the load increases. Further, in tires that receive such a high load, so-called tubeless tires that do not use tire tubes are remarkably widespread, and in tubeless tires, they are fitted to the rim with a particularly strong fitting force. Tubeless tires for passenger cars are also becoming more tubeless.

[0003]

When assembling such a tire with a rim, as shown in FIG. 4, the bead bottom surface b of the bead portion a is firmly fitted to the rim seat portion d of the rim c without any gap. However, the bead outer side surface f guided by the flange e of the rim c is located between the lower side of the outer side surface f and the flange e by the outer side surface f coming into close contact with the tip of the flange e at the time of rim assembly. A void g is generated in

The gap g gradually decreases as the outer surface f becomes familiar with the use of the tire, but the rim assembly accuracy changes as the gap g decreases.
The uniformity of tires such as radial force variation, lateral force variation, and balance may deteriorate, and vibration may be induced in actual vehicle running. Further, the contact area between the bead portion and the rim is reduced, so that the frictional force between the rim and the bead portion is reduced, and when sudden braking is applied, a rim shift may occur between the bead portion and the rim seat. It impedes straightness and reduces durability.

[0005]

As a result of earnest research aimed at solving the above-mentioned problems, the inventor has used it in a post-cure inflator process (hereinafter referred to as PCI process) which is a cooling process after vulcanizing a tire. For the shape retention rim that is used,
When assembling the vulcanized tire into the rim, if there is a void similar to the above between the bead portion and the shape-retaining rim, the bead portion is modeled with the void formed and the bead portion is formed. I knew that the shape of was decided.

Therefore, even when the tire thus shaped is fitted to the regular rim after the tire is completed, a gap exists between the regular rim and the bead portion, and this gap is regular. It was found that it cannot be easily removed when assembled with the rim. As a result, it has been found that a method of accurately fitting and cooling the shape-retaining rim in the tire manufacturing process, particularly in the PCI process, is required,
In addition, the manufacturing method of the present invention was completed by paying attention to providing an air vent hole in the rim flange of the shape-retaining rim.

According to the present invention, in the step of cooling a vulcanized tire, the rim flange of the shape-retaining rim used in the step is basically provided with four or more air vent holes, and the rim is assembled to the regular rim. At the same time, it is an object of the present invention to provide a tire manufacturing method capable of preventing rim displacement and maintaining running stability.

[0008]

SUMMARY OF THE INVENTION The present invention is a method for manufacturing a tire including a step of fitting a tire vulcanized and molded by a vulcanizer to a shape-retaining rim and cooling the tire with internal pressure filled. , The rim flange of the shape retaining rim to which the bead portion of the tire is attached has a hole diameter of 0.
Manufacture of a tire characterized in that at least four air vent holes of 5 mm or more and 5 mm or less are arranged in the circumferential direction in a height region between the rim base and 0.5 times or less the height of the rim flange. Is the way.

Further, it is preferable that the rim flange is provided with a narrow groove for connecting the air vent hole to the inner surface of the rim flange that supports the bead portion.

[0010]

The method of manufacturing a tire according to the present invention includes a step of cooling a vulcanized tire using a shape-retaining rim having an air vent hole having the above-mentioned structure. Therefore, when the rim is assembled to the shape-retaining rim, the air existing in the gap between the outer surface of the bead and the rim flange is discharged through the air vent hole, so that the bead portion can closely contact the rim flange and the bead portion Can be shaped to fit the contour rim.

Therefore, the tire cooled by using the shape-retaining rim having the above-mentioned structure can be fitted accurately along the regular rim when the rim is assembled to the regular rim, and the bead portion and the rim flange of the regular rim are fitted together. There is no gap between them.
Therefore, the accuracy of the rim assembly with respect to the regular rim is increased and the accuracy does not change over time, so that the uniformity of the tire is maintained, and the running stability can be maintained for a long period of time without the vibration being induced in the actual vehicle running. Moreover, since the rim does not come off, the durability of the tire can be improved.

If the number of air vent holes is 4 or less, when the bead portion is rim-assembled to the shape-retaining rim at the intermediate portion between the holes, a gap is likely to be formed between the rim flange and the side surface of the bead portion. Further, if the diameter of the air vent hole is less than 0.5 mm, the air flow path is narrow and easily clogged during use, resulting in insufficient discharge of air, resulting in the formation of the void. On the other hand, if the diameter of the air vent hole exceeds 5 mm, the strength of the rim flange will decrease,
Since it is easily deformed, the rim assembly accuracy is inferior because the tire assembled to the shape retaining rim is wavy.

When the height of the air vent hole from the rim base is higher than 0.5 times the height of the rim flange, the bead portion and the rim flange closely contact each other to block the air vent hole. Exhaust of air in the vicinity becomes insufficient, and air tends to remain in the gap.

When a narrow groove is formed on the inner surface of the rim flange to connect the air vent hole, the air existing in the gap between the bead portion, the outer surface and the rim flange is guided to the air vent hole through the narrow groove. It is possible to bring the bead portion into close contact with the rim flange more accurately.

[0015]

DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings. 1 to 3, a tire manufacturing method (hereinafter referred to as a method) includes a so-called PCI step in which a tire TO vulcanized and molded by a vulcanizer is fitted to a shape-retaining rim JO and cooled in a state of being filled with an internal pressure. I'm out.

The completed tire T1 is rim-assembled with a regular rim J1 fitted to the tire T1 as shown in FIG.

The completed tire T1 is formed as a pneumatic tire, and is located on both sides of the tread portion 12 inward in the tire radial direction and inside of the sidewall portion 13 in the radial direction. The tire bead portions 2 and 2 are provided, and the toroidal carcass 17 passing through the sidewall portions 13 and 13 and the tread portion 12 is bridged between the bead cores 16 and 16 provided in the tire bead portions 2 and 2. The belt layer 19 is arranged on the outer side in the radial direction and inside the tread portion 12.

The carcass 17 is a so-called radial or semi-radial direction array in which the carcass cords are arranged at an angle of 60 to 90 degrees with respect to the equator C of the tire in this embodiment, and as the carcass cord, nylon or polyester is used. Fiber cords such as rayon and aromatic polyamide are used.

The belt layer 19 is provided with belt cords which are inclined with respect to the respective belt plies forming the belt layer 19 and intersect with each other. The belt cords, like the carcass 17, are nylon, polyester, rayon, Steel cords are used in addition to fiber cords such as aromatic polyamide.

The regular rim J1 is a rim base 5A on which the bead bottom surface 3 of the bead portion 2 is seated, as shown in FIG.
And the bead portion 2 from the outer end in the tire axial direction of the rim base 5A.
And a rim flange 6A rising along the outer side surface 4 of the.

The shape-retaining rim JO is a rim used for maintaining the regular shape of the tire TO which has been vulcanized and molded as described above.
As shown in FIG. 5, the rim base 5B is formed in substantially the same shape and size as the regular rim J1 and on which the bead bottom surface 3 of the tire TO is seated, and the rim flange 6B that supports the outer side surface 4 of the bead portion 2 are provided.

The rim flange 6B of the shape-retaining rim JO is provided with a plurality of air vent holes 7 ... As shown in FIGS. The air vent hole 7 has an inner surface 9 of the rim flange 6B,
Four or more are penetrated between the outer surfaces 10 and are arranged at substantially equal intervals along the circumferential direction. The hole diameter D is set to 0.5 mm or more and 5 mm or less.

The air vent hole 7 has a rim base 5B,
It may be arranged in a height region H2 which is 0.5 times or less of the height H1 of the rim flange 6B, and the respective air vent holes 7 ... May have different heights within the height region.

The pitch P between the adjacent air vent holes L7, 7 is preferably three times or more the air vent hole diameter D in order to secure the rigidity and strength of the rim flange 7B.

Further, in this embodiment, a narrow groove 11 connecting the air vent holes 7 ... to the inner surface 9 of the rim flange 6B of the shape-retaining rim JO.
Is recessed. The narrow groove may be a straight groove connecting the air vent holes 7, 7 with a straight line, a curved groove as shown in FIG. 3, or a zigzag groove. The groove width of the narrow groove 11 is preferably in the range of the hole diameter of the air vent hole 7, that is, 0.5 to 5 mm, and the groove depth is preferably 0.25 times or less the thickness of the rim flange 6B.

When the vulcanized tire TO is cooled, it is fitted on the shape-retaining rim JO. When the outer surface 4 of the bead portion is brought closer to the rim flange 6B during fitting, the air present between the outer surface 4 and the inner surface of the rim flange 6B is discharged to the outside through the air vent holes 7. Therefore, the gap g does not remain along the outer surface near the bottom surface of the bead as shown in FIG. Therefore, in the PCI step of performing the cooling, the bead portion 2 is accurately formed along the shape-retaining rim JO.

As a result, even when the completed tire T1 is rim-assembled to the regular rim J1, a highly accurate rim assembly can be performed without forming a gap between the bead portion 2 and the rim flange 6A.

[0028]

As described above, according to the manufacturing method of the present invention, the rim flange of the shape-retaining rim used for cooling the vulcanized tire has a regulated hole diameter and penetrates at least 4 mm.
Since the purpose is to provide individual air vent holes in the area of regulated height, when fitting a vulcanized tire to the shape-retaining rim, there is a gap due to an air pocket between the rim flange of the bead portion and the rim flange. It is possible to fit the bead portion along the shape-retaining rim with high accuracy without existing. Therefore, by accurately molding the bead portion in the cooling step, a rim assembly with high accuracy can be formed on the regular rim even when the rim is assembled after the tire is completed, and there is no rim displacement which has been apt to occur in the past, and uniformity is enhanced. Therefore, it is possible to suppress the occurrence of vibration during traveling, improve the traveling stability, and improve the durability of the tire.

[Brief description of drawings]

FIG. 1 is a cross-sectional view showing a tire formed by using the manufacturing method of the present invention in a state where a tire is assembled to a regular rim.

FIG. 2 is a partial cross-sectional view showing a vulcanized tire and a shape-retaining rim in a rim-assembled state.

FIG. 3 is a perspective view showing a main part of the shape-retaining rim.

FIG. 4 is a cross-sectional view showing a conventional technique.

[Explanation of symbols]

 2 Bead part 5B Rim base 6B Rim flange D Hole diameter JO Shape retention rim TO Vulcanized tire

Claims (2)

[Claims] 1. A method of manufacturing a tire, comprising the steps of fitting a tire vulcanized and molded by a vulcanizer to a shape-retaining rim and cooling the tire while the internal pressure is filled, wherein a bead portion of the tire is attached. In the rim flange of the shape-retaining rim, at least four air vent holes penetrating the rim flange and having a hole diameter of 0.5 mm or more and 5 mm or less are formed on the rim base and 0.5 times or less of the height of the rim flange. A tire manufacturing method characterized in that the tires are arranged in a circumferential direction in a height region between them. 2. The method for manufacturing a tire according to claim 1, wherein the rim flange is provided with a narrow groove connecting the air vent hole to the inner surface of the rim flange supporting the bead portion.