JP2011189666A - Method for manufacturing bladderless pneumatic tire - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for manufacturing a bladderless pneumatic tire further reduced in cost by forming a toe part of a bead part accurately and surely into desired shape and simplifying a manufacturing process and a manufacturing apparatus in part. <P>SOLUTION: The method for manufacturing the bladderless pneumatic tire by vulcanization-molding after mounting a green tire into a vulcanizer comprising a die for molding tire shape and a bead ring, includes sticking a toe member made of crude rubber, to the outer peripheral surface of the bead ring over the circumferential direction, mounting the green tire into the vulcanizer so that a bead part of the green tire abuts on the toe member stuck to the bead ring, and then vulcanizing the green tire and the toe member integrally. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a method for manufacturing a bladderless pneumatic tire.

  Conventionally, in a method for manufacturing a pneumatic tire, a green tire is set in a vulcanizer mold, a bladder is inserted inside the green tire, and high-temperature and high-pressure steam or hot water is supplied into the bladder to remove the bladder. The raw tire was inflated and pressed against the inner surface of the mold for vulcanization.

  However, when a raw tire is vulcanized using a bladder, heat transfer from the high-temperature and high-pressure heated pressurized fluid to the raw tire is performed through the bladder, so that heat transfer is hindered by the bladder and energy efficiency is lowered. Further, as a result of the exposure of the bladder to the high-temperature and high-pressure heated pressurized fluid, the bladder is damaged in a short period of time, and the bladder needs to be replaced, resulting in an increase in cost. Furthermore, it is difficult to reduce costs because it requires a step of setting the bladder in a vulcanizer and a step of applying a release agent for peeling the bladder from the formed tire to the outer surface of the bladder. It was.

  Therefore, in order to eliminate these disadvantages in the tire manufacturing method using a bladder, a bladderless pneumatic tire manufacturing method in which vulcanization molding is performed without using a bladder has been proposed.

  In such a method of manufacturing a bladderless pneumatic tire, a raw tire is set in a vulcanizer, and then a heated and pressurized fluid is directly supplied into the raw tire so that the raw tire is pressed against a mold and a bead ring. It is possible to improve energy efficiency without hindering heat transfer by the bladder, eliminating the need for a bladder, eliminating the need for a step for setting a bladder and a step for applying a release agent, thereby reducing costs. I was able to.

  On the other hand, in the manufacturing method using the bladder, the raw tire is pressed against the mold or bead ring by the bladder whose internal pressure is increased, so that the toe tip at the tip of the bead portion receives the pressing force from the bladder and the bead ring, and the toe tip It was possible to form a toe part with a sharp tip at the tip of the raw rubber, but because the bladderless pneumatic tire manufacturing method does not use a bladder, the rubber at the toe part of the bead part Rubber flow did not occur, and the toe was rounded, resulting in low product value.

  Therefore, a bladderless pneumatic tire manufacturing method and manufacturing apparatus (Japanese Patent Application Laid-Open No. Hei 2-21205) capable of forming the toe tip into an acute angle shape by sandwiching and vulcanizing the bead portion with a bead ring and a gripping member. JP, 2001-315128, A) was proposed.

JP-A-2-21205 JP 2001-315128 A

  These bladderless pneumatic tire manufacturing methods and manufacturing apparatuses sandwich a bead portion with a gripping member and a bead ring at the time of vulcanization, and generate a rubber flow at the toe portion of the bead to form a sharp toe tip. It is possible to do that.

  In the bladderless pneumatic tire disclosed in Patent Document 1, a green tire is set in a mold of a vulcanizer, and a gripping member for gripping a bead portion of the green tire is contracted from a center position of the green tire. After that, the gripping member is expanded in the outer circumferential direction of the raw tire, the bead portion of the raw tire is sandwiched between the gripping member and the bead ring, the raw tire is sealed, and then steam or hot water is injected into the raw tire. Thus, the raw tire is inflated, and the raw tire is vulcanized by pressure contact with the inner surface of the vulcanization mold.

  A bladderless pneumatic tire vulcanizer disclosed in Patent Document 2 includes a pair of gripping members that respectively press a pair of tire bead portions against a bead ring of a mold at a center position of a mold that accommodates a raw tire. A center mechanism for displacing the tire in the tire radial direction and the tire axial direction is provided, and the pushing amount of the gripping member with respect to the bead ring can be changed according to the volume of the tire bead portion.

  In the method of manufacturing a bladderless pneumatic tire described in Patent Document 1, in order to form the bead portion of the raw tire into an acute-angled shape, the bead portion of the raw tire is sandwiched and held between the grip member and the bead ring. Since the displacement amount for sandwiching the bead portion of the gripping member is constant, the volume of the space required to form the bead portion formed by the gripping member and the bead ring in the state where the bead portion is sandwiched is fixed. Since the amount of raw rubber in the bead portion of the raw tire is less than the volume of space required to form the bead portion, it cannot be properly handled, so the rubber flow in the bead portion does not occur and the bead portion The toe tip shape could not be formed into the desired shape.

  Furthermore, when manufacturing tires with different toe tip shapes, in order to accurately form the toe tip shape, the volume of the space existing between the bead ring, the sector and the mold in accordance with the different toe tip shapes. It is necessary to match the volume of raw rubber in the bead part with each other, and the bead ring, sector and mold of the manufacturing apparatus must be changed for each different shape of the toe tip, which increases the manufacturing process and enormous cost. It has occurred.

  Further, in the vulcanizer described in Patent Document 2, as a means for improving the reproducibility of the toe tip shape of the bead part, the pressing amount of the gripping member that presses the bead part on the bead ring can be freely set according to the volume of the bead part. The changeable means can be used for manufacturing different toe tip shapes, but the center of displacement in the tire radial direction and the tire axial direction so that the pushing amount of the gripping member can be freely changed. A mechanism is required and a great manufacturing cost cannot be avoided.

  Even if the pressing amount of the gripping member can be freely changed, if the pressing amount of the gripping member is increased, a gap is generated between the divided gripping members, and the rubber of the bead portion pressed from the gap As a part of the flowed out, burrs were generated in the vulcanized and molded bead part, and the product accuracy was inferior. Further, in order to remove this burr, a separate manufacturing process is required, which further increases the cost.

  The present invention overcomes such difficulties, and can accurately and reliably form the toe portion shape of the bead portion into a desired shape, and by simplifying a part of the manufacturing process and manufacturing apparatus. An object of the present invention is to provide a method for manufacturing a tire that can further reduce the cost.

  The invention of the method for producing a bladderless pneumatic tire according to claim 1 is a bladderless pneumatic tire in which a raw tire is inserted into a vulcanizer equipped with a mold for molding a tire and a bead ring and then vulcanized. In the tire manufacturing method, a raw rubber toe member is attached to the outer peripheral surface of the bead ring in a circumferential direction, the bead portion of the raw tire, and the toe member attached to the bead ring; The raw tire and the tow member are integrally vulcanized after charging the raw tire into a vulcanizer so as to come into contact with each other.

  According to a second aspect of the present invention, in the first aspect of the present invention, the raw rubber is extruded into a ribbon shape, and the shape of the bead portion of the outer peripheral surface of the bead ring is molded while overlapping a part of the ribbon-shaped raw rubber. Therefore, the tow member is manufactured by wrapping around an outer peripheral surface formed for this purpose.

  The invention of claim 3 is the invention of claim 1, wherein the tow member is manufactured by extruding raw rubber from a die having the same shape as the cross-sectional shape in the surface orthogonal to the circumferential direction of the tow member. It is a feature.

  According to a fourth aspect of the present invention, in the first to third aspects of the present invention, the cross-sectional shape of the toe member on a surface orthogonal to the circumferential direction of the bead ring is a circle at a toe tip portion of a tire bead portion. The tow member is manufactured so as to have the same cross-sectional shape in a plane orthogonal to the circumferential direction.

  In the first aspect of the invention, when the raw tire is vulcanized, a tow member made of raw rubber is previously pasted on the outer peripheral surface of the bead ring, and the raw tire and the toe member are integrally vulcanized. A toe shape with high accuracy can be formed, and a tire with high product value can be manufactured. In addition, a gripping member and a central mechanism are not required, and a part of the structure of the manufacturing apparatus can be simplified, and the manufacturing cost can be reduced. Furthermore, even when manufacturing tires with different toe tip shapes, by changing the shape of the toe member to be pasted, various toe tip shape tires can be easily manufactured, and the manufacturing process is simplified. Manufacturing cost can be reduced.

  In the invention according to claim 2, since the toe member is manufactured by wrapping raw rubber extruded in a ribbon shape on a bead ring and winding it, even when manufacturing a tire having a different toe tip shape, By changing the winding amount and winding position of the raw rubber, it is possible to easily produce a tire having a required toe shape, and to reduce the manufacturing cost.

  In the invention according to claim 3, the toe member is formed by extruding raw rubber from the same base as the cross-sectional shape of the desired toe tip member, so that it is possible to accurately and surely form a highly accurate toe tip shape. Thus, a high-quality tire can be manufactured. Further, even when a tire having a different toe tip shape is manufactured, it can be dealt with by changing to a base having a different toe tip shape, and the manufacturing cost can be reduced.

  In the invention according to claim 4, the cross-sectional shape in the surface orthogonal to the circumferential direction of the bead ring of the toe member is the same as the cross-sectional shape in the surface orthogonal to the circumferential direction of the toe tip portion of the bead portion of the tire as a product. Therefore, it is possible to manufacture a bladderless pneumatic tire with high product accuracy and to reduce costs.

It is the longitudinal cross-sectional view which illustrated the arrangement | positioning relationship of the structural member of the green tire manufactured by the manufacturing method of the bladderless pneumatic tire of this invention. It is a longitudinal cross-sectional view of the green tire manufactured by the manufacturing method of the bladderless pneumatic tire of this invention. It is the longitudinal cross-sectional view which conveyed the raw tire shown in FIG. 2 to the vulcanizer of the state where the metal mold | die opened. It is a perspective view which shows the state which winds the ribbon-shaped raw rubber extruded by the extruder around a bead ring, and manufactures a toe member. It is a longitudinal cross-sectional view which shows the state by which the tow member of FIG. 4 was affixed on the bead ring. It is a longitudinal cross-sectional view which shows the state by which the green tire shown in FIG. 3 was mounted in the lower side mold. It is a longitudinal cross-sectional view which shows the state which lowered | hung the upper platen of the vulcanizer of FIG. 6, and the upper side mold approached the green tire. FIG. 8 is a longitudinal sectional view showing a state where the upper platen of the vulcanizer of FIG. 7 is further lowered, the upper side mold is pressed against the green tire, and the tread mold is closed. It is a longitudinal cross-sectional view of the bladderless pneumatic tire manufactured by the manufacturing method of the bladderless pneumatic tire of this invention. It is a perspective view which shows the state which extrudes raw rubber from the nozzle | cap | die formed in the cross-sectional shape of the desired toe member with an extruder, forms a toe member, and affixes the said toe member on a bead ring.

  Hereinafter, an embodiment of the present invention shown in FIGS. 1 to 9 will be described.

  The manufacturing method of the pneumatic tire of the present invention is as follows.

  First, as shown in FIG. 1, the inner liner 3 is attached to the forming drum 20, the chafer 4 is attached to both sides of the inner liner 3, and the carcass ply 5 is attached to the outer peripheral surfaces of the inner liner 3 and the chafer 4. After the pasting, the chafer 4 and the carcass ply 5 are folded back so as to cover most of the bead filler 7 in which the bead wire 6 is contained, and the chafer 4, the bead filler 7 and the carcass ply 5 have a predetermined cross-sectional shape. 2 are pasted and molded into a predetermined shape, and then a belt 9 and a tread 10 are pasted at the center in the width direction of the carcass ply 5 to add the bladderless pneumatic tire 1 shown in FIG. A pre-sulfur green tire 2 is manufactured.

  The inner liner 3, chafer 4, bead wire 6, and bead filler 7 constitute a raw tire bead portion 11.

The molded green tire 2 is then vulcanized by a vulcanizer 22 shown in FIG.
The vulcanizer 22 includes an upper platen 23a that can be moved in the vertical direction by hydraulic pressure, a lower platen 23b that is fixed to a vulcanizer base (not shown), and a pair of upper and lower side molds 24 that form the shape of a tire sidewall. And a tread mold 25 that forms a tread shape and is divided into a plurality of parts in the circumferential direction, and a pair of bead rings 26 that form the shape of the bead portion of the tire.

  An upper side mold 24a is fixed to the upper platen 23a of the vulcanizer 22, a lower side mold 24b is fixed to the lower platen 23b, and an upper bead ring 26a is fixed to the lower platen 23b. The bead rings 26b are detachably engaged with each other. The split tread mold 25 can be opened and closed by a hydraulic mechanism or a mechanical mechanism and can be opened and closed. When the divided tread mold 25 is moved and closed in the inner diameter direction, its inner peripheral surface has a ring shape. Yes.

  As shown in FIG. 4, the bead ring 26 has, as an outer peripheral surface, a bead portion forming surface 27 that forms the shape of the bead portion, a side mold contact surface 28 that contacts the side mold, an inner peripheral surface 29, and an outer surface. The platen engaging surface 30 and the inner side surface 31 are engaged with the platen. The bead part forming surface 27 of the bead ring 26 is formed in a shape that matches the bead part 40 (see FIG. 9) of the product of the bladderless pneumatic tire 1.

  As shown in FIGS. 4 and 5, the bead part forming surface 29 of the bead ring 26 has a cross-sectional thickness of about 0.2 mm to 0.4 mm and a width of about 3 mm to 4 mm from the die 34 of the extruder 33. The ribbon-shaped raw rubber 13 extruded into a substantially rectangular shape is spirally wound on the bead portion forming surface 27 of the bead ring 26 while overlapping a part thereof, and the toe member 12 of the ribbon laminate is formed. The toe member 12 is formed in the same shape as the toe shape 41 (see FIG. 9) of the bead portion 40 of the bladderless pneumatic tire 1 desired as a product by computer control.

  The raw tire 2 conveyed to the vulcanizer 22 is vulcanized together with the tow member 12 as follows.

  First, as shown in FIG. 3, the upper platen 23a of the vulcanizer 22 is moved upward, the divided tread mold 25 is expanded, and the upper and lower bead rings 26a, 26b on which the tow members 12 are attached are moved to the upper platen. Engage with each of 23a and lower platen 23b.

  Thereafter, the raw tire 2 is conveyed to the center position of the vulcanizer 22 by the conveying tool 21, and the chafer 4b of the lower raw tire bead portion 11b is attached to the lower bead ring 26b as shown in FIG. The raw tire 2 is placed on the lower side mold 24b and the lower bead ring 26b so as to be in contact with the lower toe member 12b.

  Further, as shown in FIGS. 7 and 8, when the upper platen 23a is lowered, the upper side mold 24a and the upper bead ring 26a integrated with the upper platen 23a are lowered, and the upper side mold 24 is attached to the raw tire 2. The upper bead ring 26a and the toe member 15a attached to the upper bead ring 26a are in contact with the upper chafer 4b.

  Further, the tread mold 25 is moved inward in the diameter of the raw tire 2 and contracted, the tread mold 25 is pressed against the tread 7 of the raw tire 2, and the chafer 4 and the tow member 11 of the raw tire 2 are pressed.

  Thereafter, a heat medium such as steam or hot water is press-fitted into the vulcanizer 22 and heated under pressure for a predetermined time, whereby the raw tire 2 and the toe member 12 are integrally vulcanized, and the raw tire bead portion 11 And the toe member 12 are integrated, and the bladderless pneumatic tire 1 is manufactured.

  In the method of manufacturing the bladderless pneumatic tire of the present embodiment, the toe member 12 formed in a desired shape as a product is pasted on the bead ring 26 in advance, so that the toe tip shape of the bead portion is a predetermined shape. Therefore, it is possible to manufacture a tire with high product accuracy.

  In addition, a holding mechanism such as a gripping member for making the toe tip shape an acute angle is unnecessary, and it is not necessary to apply a release agent, simplifying the manufacturing equipment and reducing the manufacturing process, thereby reducing the cost. Can be achieved. Furthermore, since the burrs due to the gaps between the gripping members do not occur, the product accuracy is improved, and the process of removing the burrs is not necessary, and the cost can be reduced.

  Further, since the tow member 12 is a ribbon laminated body formed by computer control, even when manufacturing toe-shaped tires having a variety of different beads, the shape of the toe member is changed by a computer. In addition to this, it is possible to cope with the problem by changing the bead ring to which the tow member is attached, and it is not necessary to replace the devices such as the gripping member and the sector, and the manufacturing cost can be reduced.

  In the embodiment described above, the bladder-less pneumatic tire 1 is manufactured by pasting the tow member 12 made of a ribbon laminate on the bead portion forming surface 27 of the bead ring 26. However, as shown in FIG. Is extruded from the extruder 33 through the base 35 formed in the cross-sectional shape of the desired tow member to form the toe member 14, and the tow member 14 is attached to the bead portion forming surface 27 of the bead ring 26. And a bladderless pneumatic tire may be manufactured.

  According to such a method of manufacturing a bladderless pneumatic tire, when manufacturing a toe-shaped tire with a different bead, it is only necessary to replace the base 35 with a predetermined cross-sectional shape, so that it can be easily handled. Can be achieved, and the manufacturing cost can be reduced. In addition, since the toe member 14 is extruded into a predetermined cross-sectional shape by the base 35, the shape of the toe tip portion of the bead portion of the tire becomes a uniform shape in the circumferential direction, and a high-quality tire can be manufactured. Furthermore, mass production is possible, and the manufacturing cost can be reduced.

  DESCRIPTION OF SYMBOLS 1 ... Bladderless pneumatic tire, 2 ... Raw tire, 3 ... Inner liner, 4 ... Chafer, 5 ... Carcass ply 6 ... Bead wire, 7 ... Bead filler, 8 ... Side wall, 9 ... Belt, 10 ... Tread, 11 ... Raw tire Bead part, 12 ... toe member, 13 ... ribbon-like raw rubber, 14 ... toe member, 20 ... molding drum, 21 ... conveying tool, 22 ... vulcanizer, 23 ... platen, 24 ... side mold, 25 ... tread mold, 26 ... Bead ring, 27 ... Bead part forming surface, 28 ... Side mold contact surface, 29 ... Inner peripheral surface, 30 ... Platen engaging surface, 31 ... Inner side surface, 33 ... Extruder, 34 ... Base, 35 ... Base, 40 ... Bead part, 41 ... Toe tip.

Claims (4)

In a method for producing a pneumatic bladderless tire in which a raw tire is inserted into a vulcanizer equipped with a mold for molding a tire shape and a bead ring, and then vulcanized and molded.
A raw rubber tow member is attached to the outer peripheral surface of the bead ring over the circumferential direction,
After charging the green tire into the vulcanizer so that the bead portion of the green tire and the toe member attached to the bead ring are in contact with each other,
A method for manufacturing a bladderless pneumatic tire, wherein the green tire and the tow member are vulcanized together.   The tow member is formed by extruding raw rubber into a ribbon shape and winding the ribbon-like raw rubber around the outer peripheral surface formed to mold the shape of the bead portion of the outer peripheral surface of the bead ring. The method for manufacturing a bladderless pneumatic tire according to claim 1, wherein:   2. The method for manufacturing a bladderless pneumatic tire according to claim 1, wherein the toe member is manufactured by extruding raw rubber from a die having the same shape as a cross-sectional shape on a surface orthogonal to the circumferential direction of the toe member. .   The cross-sectional shape in the surface orthogonal to the circumferential direction of the bead ring of the toe member is the same as the cross-sectional shape in the surface orthogonal to the circumferential direction of the toe tip portion of the bead portion of the bladderless pneumatic tire, 4. The method of manufacturing a bladderless pneumatic tire according to claim 1, wherein a toe member is manufactured.

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