JPH08216284A - Manufacture of solid tire - Google Patents

Abstract

PURPOSE: To raise uniformity of a finished tire by excluding eccentricity of a green cover, and motion on a clip ring of a base rubber by a method wherein a sheet-like base rubber is wound on a winding frame of a molding former which is made the same shape as that of the clip ring of a vulcanizing mold. CONSTITUTION: A base rubber part 5 forming a base rubber layer 2 winds a sheet-like base rubber A in multi-layers from a radial direction inside toward its outside on a winding frame 10 or a molding former 11 having the same shaped outer surface 10A as that of an outer surface supporting a tire bead part of a clip ring 9 of a vulcanizing mold 7. Further, a tread rubber part 6 forming a tread rubber layer 3 is formed having a larger width WT than a width W outside in a radial direction of a base rubber part 5 by winding a sheet-like tread rubber in multi-layers from inside to outside in the radial direction, and a donut-like green cover 12 is formed. The green cover 12 wound on the clip ring 9 is pressurized with a bottom force 15 and a top force 16 of the vulcanizing mold 7 having a tire equatorial surface of a solid tire 1 to be molded as divided surface, and vulcanized.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a solid tire manufacturing method capable of efficiently producing a solid tire having high uniformity.

[0002]

2. Description of the Related Art A pneumatic solid tire t is, as shown in FIG. 4, a base rubber layer a made of hard rubber or short fiber reinforced rubber on the rim r side, and arranged on the outer side in the radial direction thereof. A two-layer structure having a JIS A hardness of 60 to 70 ° and a tread rubber layer b made of a rubber softer than the base rubber layer a is known.

Further, as shown in FIG. 5, the base rubber layer a is conventionally formed by winding a sheet-shaped base rubber ar in multiple layers from the inner side to the outer side in the radial direction on a drum-shaped molding home c. Doughnut-shaped raw cover tr that is formed into a sheet shape and has a sheet-shaped tread rubber br wound in multiple layers on the radial outside of the base rubber ar.
The solid tire t is manufactured by applying a pressing pressure in a vulcanization mold and integrally vulcanizing.

[0004]

However, in the case where the raw cover tr molded on the molding homer c is put into a vulcanization mold, as shown in FIG. 6, the tire holding of this vulcanization mold is performed. Since the doughnut-shaped raw cover tr having a substantially rectangular cross section is wound around the clip ring d for use with the tire, a gap g is generated between the outer peripheral surface d1 for forming the tire bead portion of the clip ring d and the raw cover tr. However, the eccentricity of the raw cover tr during vulcanization, the uneven movement of the base rubber ar, and the like impair the uniformity of the finished tire, resulting in an increase in radial runout.

Further, in the conventional one using the sheet-shaped tread rubber br, it takes a lot of time to wind the tread rubber br, the productivity may be lowered, and the solid raw cover tr is vulcanized. There is also a problem that vulcanization for a very long time is required and further productivity is reduced.

The present invention is based on the fact that a sheet-shaped base rubber is wound around a winding frame of a molding home having the same shape as the clip ring of the vulcanizing die, and the raw cover is used as the clip ring of the vulcanizing die. It is an object of the present invention to provide a method for manufacturing a solid tire that can eliminate the eccentricity of the raw cover and the movement of the base rubber onto the clip ring during installation, improve the uniformity of the finished tire, and particularly reduce the radial runout.

[0007]

The present invention is a solid tire manufacturing method for manufacturing a pneumatic solid tire comprising a base rubber layer on the rim side and a tread rubber layer on the tread surface side. Multiple layers of sheet-shaped base rubber are wound on the winding frame of the molding homer that has the same shape as the clip ring of the metal mold to form a base rubber portion close to the finished width of a solid tire, and the radial direction of this base rubber portion. A raw cover is molded by arranging a tread rubber portion on the outside, and the raw cover is vulcanized by a vulcanization mold.

The base rubber layer preferably includes a reinforcing layer made of steel cord or organic fiber cord.

The tread rubber portion is preferably formed in a ring shape by injection molding.

[0010]

The base rubber portion of the green cover is formed by winding the sheet-shaped base rubber in multiple layers on the winding frame of the molding home having the same shape as the clip ring of the vulcanizing die.
Therefore, when removing the raw cover from the molding home and winding it around the clip ring of the vulcanization mold, it is possible to prevent eccentricity of the raw cover or uneven movement of the base rubber portion,
It can improve the uniformity of the finished tire, increase the roundness, and especially reduce the radial runout. As a result, by using the manufacturing method according to the present invention, the solid tire is
Vibration during traveling can be suppressed and riding comfort can be improved.

Further, in the invention of claim 2, when the base rubber layer is provided with a reinforcing layer made of steel cord or organic fiber cord, the fitting force with the rim can be increased and rim slip can be effectively prevented. In addition, since the base rubber layer can be easily reinforced by the reinforcing layer when the base rubber is wound, the productivity can be improved without mixing the short fiber cord into the base rubber.

Further, in the invention of claim 3, when the tread rubber portion is formed by injection molding, the molding is easier and the vulcanization time can be shortened and the productivity is improved as compared with the case where the sheet-shaped tread rubber is wound. With the possibility
It has less thermal expansion during vulcanization and can prevent appearance deterioration such as trim cracks and improve the appearance. Further, it is possible to reduce the risk that bubbles are generated in the tread rubber layer and further improve the uniformity of the tire.

[0013]

DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings. The pneumatic solid tire 1 manufactured by the manufacturing method of the present invention includes a base rubber layer 2 on the rim side and a tread rubber layer 3 on the tread surface side as shown in FIG.

The base rubber layer 2 has a height HB from the bead base line BL of 30 to 30 which is a tire cross-section height TH.
The rubber composition is set in the range of 70%, is reinforced with carbon, and is formed using a rubber composition in which short fibers having a JIS A hardness of 75 to 90 ° are not mixed or a mixed rubber composition.

The height HB is 30 which is the tire cross-section height TH.
If it is less than 70%, the fitting force with the rim cannot be maintained, and conversely, if it exceeds 70%, the cushioning property is significantly deteriorated.

The base rubber layer 2 also comprises a reinforcing layer 4.
The reinforcing layer 4 is a plurality of sheets formed by spirally winding an organic fiber cord covered with topping rubber in the present embodiment in the tire circumferential direction and at a small angle with respect to the tire equator. It consists of plies.

The organic fiber cord is a cord for fabric such as nylon, polyester, etc., and the elastic modulus is preferably 600 kg / cm ² or more, and the 300% modulus is 40 to 150 when the cords are aligned.
A band-shaped ply for spiral winding can be formed by topping with a calendar using a rubber of kg / cm ² .
A steel cord may be used instead of the organic fiber cord.

The tread rubber layer 3 uses a rubber having a JIS A hardness of 50 to 70 °, and has a rubber composition excellent in abrasion resistance, crack resistance and gripping property, such as natural rubber, isoprene rubber and styrene. -A so-called tread compound in which a predetermined amount of carbon is compounded in a diene rubber such as butadiene rubber is used. If the JIS A hardness is less than 50 °, the wear resistance is poor, and conversely if it exceeds 70 °,
The grip performance is reduced.

The base rubber portion 5 forming the base rubber layer 3 is the same as the outer surface 9A (shown in FIG. 2) that supports the tire bead portion of the clip ring 9 of the vulcanization mold 7, as shown in FIG. By winding the sheet-shaped base rubber in multiple layers from the inner side to the outer side in the radial direction on the winding frame 10 of the molding home 11 having the outer surface 10A in a shape, a width W close to the finished width of the solid tire 1 is obtained. Formed.

When the base rubber is wound, the reinforcing layer 4 is interposed between the laminated base rubbers.

On the outer side in the radial direction of the base rubber portion 5,
The tread rubber portion 6 forming the tread rubber layer 3,
A sheet-shaped tread rubber is wound in multiple layers from the inner side to the outer side in the radial direction to have a width WT larger than the width W, thereby forming the doughnut-shaped raw cover 12.

The raw cover 12 is, as shown in FIG.
The clip ring 9 of the vulcanization mold 7 is wound around the outer surface 9A. At this time, the base rubber portion 5 is the molding home 1
Since it is formed on the winding frame 10 having the same shape as the clip ring 9 of No. 1, the eccentricity when the raw cover 12 is wound around the clip ring 9 and the unevenness of the base rubber portion 5 at the time of vulcanization afterwards Such movements can be suppressed as much as possible, and the uniformity of the solid tire 1 can be improved.

The green cover 12 wound around the clip ring 9 is pressed by the lower mold 15 and the upper mold 16 of the vulcanizing mold 7 having the tire equator of the solid tire 1 to be molded as a dividing surface. Then, the solid tire 1 is manufactured by vulcanization.

The tread rubber portion 6 is connected to the lower mold 1 by
It is also possible to form a ring shape by so-called injection molding in which a fluid rubber composition is injected into a space formed on the outer side in the radial direction of the base rubber portion 5 by superimposing the upper mold 16 and the upper mold 16.

In this case, since the rubber composition forming the tread rubber portion 6 is in a fluidized state, bubbles are not generated in the tread rubber layer 3 formed by this rubber composition, and a more homogeneous solid is obtained. The tire 1 can be produced.

By using injection molding, the vulcanization time can be shortened, the thermal expansion at the time of vulcanization can be reduced, the occurrence of trim cracks can be reduced, and the appearance can be improved.

[0027]

SPECIFIC EXAMPLE A solid tire having a tire size of 7.00-12 was prototyped by the manufacturing method of the present invention (example product),
Radial runout was measured. The conventional method (Fig. 6)
Also shown for the prototype (conventional product)
In addition, the radial runout was measured. The test results are shown in Table 1.

[0028]

[Table 1]

From the test results shown in Table 1, it was confirmed that the example product reduced the radial runout as compared with the conventional product.

[0030]

As described above, according to the method for producing a solid tire of the present invention, the base rubber portion of the green cover has the same shape as the clip ring of the vulcanization mold, and the sheet-shaped base is formed on the winding frame of the molding homer. It is formed by winding rubber in multiple layers. Therefore, when the raw cover is removed from the molding home and wound around the clip ring of the vulcanization mold, it is possible to prevent the eccentricity of the raw cover and the uneven movement of the base rubber portion,
It can improve the uniformity of the finished tire, increase the roundness, and especially reduce the radial runout. As a result, by using the manufacturing method according to the present invention, the solid tire is
Vibration during traveling can be suppressed, and riding comfort and steering stability can be improved.

Further, in the invention of claim 2, when the base rubber layer is provided with a reinforcing layer made of a steel cord or an organic fiber cord, the fitting force with the rim can be increased and rim slip can be effectively prevented. In addition, since the base rubber layer can be easily reinforced when the base rubber is wound without mixing the short fiber cord with the base rubber, the productivity can be improved.

Further, in the invention of claim 3, when the tread rubber portion is formed by injection molding, the molding is easier and the vulcanization time can be shortened and the productivity is improved as compared with the case where the sheet-shaped tread rubber is wound. With the possibility
It has less thermal expansion during vulcanization and can prevent appearance defects such as trim cracks and improve appearance. Further, it is possible to reduce the risk that bubbles are generated in the tread rubber layer and further improve the uniformity of the tire.

[Brief description of drawings]

FIG. 1 is a cross-sectional view showing a solid tire formed by a manufacturing method of the present invention together with a vulcanizing mold.

FIG. 2 is a cross-sectional view illustrating a raw cover together with a clip ring.

FIG. 3 is a cross-sectional view illustrating a raw cover with a molding homer.

FIG. 4 is a sectional view of a solid tire for explaining a conventional technique.

FIG. 5 is a cross-sectional view for explaining a conventional technique.

FIG. 6 is a cross-sectional view for explaining a conventional technique.

[Explanation of symbols]

 2 Base rubber layer 3 Tread rubber layer 4 Reinforcing layer 5 Base rubber part 6 Tread rubber part 7 Vulcanizing mold 9 Clip ring 10 Reel 11 Forming home 12 Raw cover

Claims (3)

[Claims] 1. A method for producing a solid tire, comprising a base rubber layer on the rim side and a tread rubber layer on the tread surface side, for producing a pneumatic solid tire, which is the same as the clip ring of the vulcanizing die. Multi-layered sheet-shaped base rubber is wound on the winding frame of a shaped homer to form a base rubber part close to the finished width of a solid tire, and a tread rubber part is arranged radially outside of this base rubber part. Thus, the raw cover is molded, and the raw cover is vulcanized by a vulcanization mold, which is a method for producing a solid tire. 2. The method for producing a solid tire according to claim 1, wherein the base rubber layer comprises a reinforcing layer made of a steel cord or an organic fiber cord. 3. The method for producing a solid tire according to claim 1, wherein the tread rubber portion is formed into a ring shape by injection molding.