JPS6343125Y2 - - Google Patents

Description

[Detailed description of the invention] This invention relates to the structure of a tire, and in particular, as a molded member on at least one of the inner and outer sides of the tire, a plurality of grooves opening on at least one of both end faces in the width direction are formed on the surface. By pasting the unvulcanized rubber sheet formed on the rubber sheet, failures due to air pockets on the surface to which the rubber sheet is pasted are prevented.

Conventionally, sheets made of unvulcanized rubber have been used when assembling and molding green tires. For example, in tubeless tires, a rubber sheet is attached to the inner surface of the tire as a molded member of the inner liner. FIG. 1 is a half-sectional view of a tubeless tire, and shows the structure of part X of the sandwall portion 2. As shown in FIG. 2
Layer the inner liner 4 and adhere the second layer.
A carcass layer 5 is stuck on the inner liner 4 of the layer, and a side tread rubber layer 6 is stuck on the surface of the carcass layer 5.

Among these tire molding members, rubber sheets used as, for example, the inner liners 3 and 4 have been conventionally finished with smooth surfaces on both the front and back surfaces.

However, when assembling and molding raw tires, if unvulcanized rubber sheets with smooth surfaces are used and pasted onto the forming drum, air that gets into the bonded surfaces between the rubber sheets can be completely eliminated. This is difficult, and air that is not removed remains on a portion of the adhesive surface, creating a cavity. Even after vulcanizing a green tire with such cavities, the cavities often remain, and an air pocket 7 as shown in Figure 3 is formed on a part of the inner surface of the tire. There is a problem in that this causes tire failure.

There is also a method in which a large number of small through holes are provided in an unvulcanized rubber sheet to eliminate air that has entered the bonding surface between the rubber sheets from the through holes. Although this prevents the formation of cavities, it is easy for water and dust to enter the through holes, and blisters and dust reduce the adhesive strength between the rubber sheets, so as mentioned above, this can cause damage to the tire. There is a problem that it can lead to failure.

This invention was made to solve the above problem, and the purpose of this invention is to attach an unvulcanized rubber sheet with multiple grooves opening on at least one of both end faces in the width direction of the surface. Another object of this invention is to provide a tire having a structure that does not cause failures due to air pockets on the surface to which the rubber sheet is attached.

That is, as shown in the examples and drawings described below, this invention has a plurality of grooves 12 on at least one surface of an unvulcanized rubber sheet 10 for molding a green tire, respectively, on both widthwise end surfaces of the sheet. The unvulcanized rubber sheet 10 is formed with an opening on at least one side, and the unvulcanized rubber sheet 10 is molded on at least one of the inner and outer sides of the tire with its width direction being the same as the axial direction when wrapping the green tire on the forming drum. The present invention relates to a structure of a tire characterized by being attached as a member.

Examples of this invention will be described below with reference to the drawings.

FIG. 4 is a perspective view showing an example of an unvulcanized rubber sheet used as a molding member for a tire of this invention.

On the surface of the unvulcanized rubber sheet 10, a sheet is drawn in the drawing direction (lengthwise direction from the top end to the bottom end in the drawing).
A large number of V-shaped grooves 12 are formed at regular intervals with respect to the center line. This groove 12
are open at both end faces in the width direction of the rubber sheet 10 and are continuously provided over the entire surface of the rubber sheet 10 from one end face to the other end face.

The dimensions of the groove 12 described above are, for example, the size of the rubber sheet 1
When the width of 0 is 700 mm and the thickness is 2 mm, it is preferable to set as follows (see Figure 5).

Groove spacing A = 10 mm Groove upper edge width B = 2 mm Groove bottom width C = 1.5 mm Groove depth D = 0.07 mm Figure 6 shows a molding drum using the unvulcanized rubber sheet of this invention for an inner liner. (not shown) shows a green tire wrapped on top.

This green tire is manufactured by pasting two inner liner rubber layers 14 and 16 on a forming drum, pasting a carcass layer 18 on the second inner liner rubber layer 16, and beating both ends of the carcass layer 18. 19, and a side tread rubber layer 20 and a tread rubber layer 22 are sequentially adhered on top of the carcass layer 18 and molded.

7 and 8 respectively show the steps from assembly and molding of the green tire shown in FIG. 6 to vulcanization for part Y of the sidewall portion. In both figures, the upper row shows each molded member before assembly, the middle row shows the molded member in a pasted state, and the lower row shows the molded member in a vulcanized state.

Figure 7 shows the first layer of inner liner rubber layer 1.
4 is an example of use in which a conventional unvulcanized rubber sheet is pasted, and the unvulcanized rubber sheet of this invention is pasted as the second inner liner rubber layer 16 with the surface where the grooves 12 are processed on the back side. be. The width direction of the inner liner rubber layer 16 is the same as the axial direction of the molding drum (the direction of the arrow in FIG. 6), and the grooves 12 are opened on both end faces, so that the inner liner rubber layers 14 and 16 The air that has entered the adhesive surface between the inner liner rubber layer 16 of the second layer
After pasting the inner liner rubber layer 1, when a stitching roller is applied to the surface and pressed, the inner liner rubber layer 1
It passes through the grooves 12 of No. 6 and is discharged to the outside from the openings on both end faces in the width direction. Therefore, no cavities are created due to air pockets. In addition, since the inner liner rubber layers 14 and 16 are in an unvulcanized state,
The groove 12 itself is crushed into a smooth surface by the pressing force of the stitching roller, or the first
The inner liner rubber layer 14 of the layer is press-fitted into the groove 1.
Since the groove 2 is in a closed state, the air that has entered the groove 12 is eventually completely exhausted.

FIG. 8 shows that the unvulcanized rubber sheets of this invention are used for both the first and second inner liner rubber layers 14 and 16, and the surfaces processed with grooves 12 and 12, respectively, are placed on the front side. This is the usage side when it is pasted. In this case as well, the air that has entered the bonding surface between both inner liner rubber layers 14 and 16 and the bonding surface between the second inner liner rubber layer and the carcass layer 18 is removed by the stitching roller. At times, the inner liner rubber layers 14, 16 are discharged through the grooves 12, 12 of the respective inner liner rubber layers 14, 16.
The air that has entered into the grooves 12, 12 also flows into the grooves 12, 12.
12 is crushed and disappears, resulting in a completely ejected state.

Running tests were conducted to compare the performance of tubeless tires in which the unvulcanized rubber sheet of this invention and the conventional unvulcanized rubber sheet were used as inner liner molding members. The failure rate is 0.01
%, whereas with conventional tires it was confirmed that failure occurred at a high rate of 0.42%.

The arrangement shape of the grooves formed on the surface of the unvulcanized rubber sheet of this invention is not limited to the above-mentioned embodiments, but can be any shape. Further, it is also possible to use an unvulcanized rubber sheet in which grooves are formed not only on one surface but also on both surfaces.

Further, although the grooves in the above embodiment are open on both end faces in the width direction of the rubber sheet, grooves may be formed that are open only on one end face, and furthermore, either one end of each groove may be formed. The openings may be formed separately on either end face of the rubber sheet.

In addition, in the above usage example, the case where the unvulcanized rubber sheet of this invention is used as an inner liner on the inner side of a tire was explained, but this invention is not limited to the inner liner of a tire, but can also be used on the outer sidewall part. Alternatively, it can also be used as a rubber layer in the tread portion.

As is clear from the above explanation, the tire of this invention has an unvulcanized rubber sheet formed with multiple grooves opened on at least one end surface in the width direction of the surface, on the inner surface of the tire. The structure is such that at least one of the outer surface and the outer surface is a molded member.
Therefore, according to this invention, no cavities are formed due to air entering the bonding surface of the rubber sheet, and a tire with high strength bond between the rubber sheets can be obtained, thereby preventing failures caused by air pockets. decreases dramatically.

In addition, when applying the unvulcanized rubber sheet of this invention as a molding member on the outer surface of a tire, if the grooved surface of the rubber sheet is used as the front side, it is possible to avoid contact with the mold during vulcanization of the green tire. At the same time, an effect is obtained in which the air trapped between the grooves can be dispersed through the grooves.

[Brief explanation of drawings]

Figure 1 is a perspective view of a semi-meridian cross section of the tire, Figure 2 is an enlarged view of the X part of Figure 1, Figure 3 is a cross-sectional view of a part of the tire with air pockets, and Figure 4 is a diagram of this invention. FIG. 5 is a perspective view showing an example of an unvulcanized rubber sheet, FIG. 5 is a partial side view thereof, FIG. 6 is a half-longitudinal sectional view showing a green tire of this invention, and FIGS. 7 and 8 are respectively FIG. 7 is a process explanatory diagram of an example of use of the Y section in FIG. 6; In the figure, 10 is the unvulcanized rubber sheet of this invention, 1
2 is a groove.

Claims (1)

[Scope of utility model registration request] A plurality of grooves are formed on at least one surface of an unvulcanized rubber sheet for molding a raw tire, each opening at at least one of both end faces in the width direction of the sheet, and the unvulcanized rubber sheet has a width 1. A tire structure characterized in that the tire is attached as a molding member to at least one of the inner and outer surfaces of the tire in the same direction as the axial direction when the green tire is wound on a molding drum.