JP2012143946A - Device and method for manufacturing tire - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent the thickness of an unvulcanized tread from becoming uneven at the molding of an unvulcanized tire.SOLUTION: In a tire manufacturing device having a tread molding device which forms the unvulcanized tread T by pasting unvulcanized tread rubber to an expandable/contractible BT drum, an elastic rubber band 14 mounted to the BT drum has an outer peripheral surface abutting on the unvulcanized tread as an irregularily-processed face 14(1) for preventing adhesion, has an inner peripheral surface being an abutment surface with a plurality of segments which diameter-expand the elastic rubber band 14 as a cloth face 14(3) adhered with cloth, and has a plurality of penetration holes 14a which penetrate the irregularily-processed face 14(1) from the cloth face 14(3) at the internal periphery side.

Description

  The present invention relates to a tire manufacturing apparatus and a tire manufacturing method for forming an unvulcanized tire by attaching an unvulcanized tread to the outer periphery of a molded body.

  In the molding process of the unvulcanized tire, an unvulcanized tread is attached to the outer periphery of the swelled molded body, and the pasted unvulcanized tread is pressed and pressed against the opposite molded body to be unvulcanized. A tire is formed (see Patent Document 1).

FIG. 4 is a diagram schematically illustrating an example of a manufacturing process in the tire manufacturing method for manufacturing a tire in this manner.
In the illustrated example, first, an unvulcanized tread T is pasted on a drum (belt tread drum (hereinafter referred to as “BT drum”)) 12 (1) of a tread forming apparatus to form an annular unvulcanized tread. (FIG. 4A). Next, the diameter of the BT drum 12 (1) is expanded (enlarged), and the annular unvulcanized tread T is expanded to a diameter slightly smaller than the diameter of the molding target H to be attached. Next, the annular hoop ring 20 is moved around the annular unvulcanized tread T, and the unvulcanized tread T is accommodated in the hoop ring 20 (FIG. 4B). The hoop ring 20 sucks and holds the annular unvulcanized tread T by its vacuum device (not shown) (FIG. 4C). Next, the diameter of the BT drum 12 (1) is reduced (reduced) (FIG. 4D), and the unvulcanized tread T is removed from the BT drum 12 (1) while being sucked by the hoop ring 20.

  Subsequently, the hoop ring 20 holding the unvulcanized tread T is moved onto the molded body H and set around the molded body H. Here, the molded body H is formed in a cylindrical shape on the molding drum 12 (2) by combining various tire constituent members such as a carcass ply and a bead core, and a cord is provided in a predetermined range on the outer peripheral surface of the bulged center portion. A belt is formed by being spirally wound. Next, when the vacuum device of the hoop ring 20 is switched from air suction (FIG. 4E) to air discharge (FIG. 4F) and the unvulcanized tread T is released, the unvulcanized tread T is reduced in diameter by its contraction force. It adheres on the molded body H (FIG. 4G). Finally, the molded body H is rotated, and the pair of pressing rollers 50 are pressed against the outer peripheral surface of the unvulcanized tread T and moved from the center in the width direction (left and right in the drawing) toward both outer sides ( FIG. 4H). As a result, the unvulcanized tread T is pressed spirally by the pair of pressing rollers 50 and stitched over the whole to press-bond the unvulcanized tread T to the molded body H.

  The unvulcanized tread T is gradually squeezed radially inward toward the end in the width direction along with stitching, and deforms in accordance with the curved outer peripheral surface of the molding H, and the inner peripheral surface is An unvulcanized tire is manufactured by sticking and sticking to the outer peripheral surface of the molded body H. Unvulcanized tires become product tires by vulcanization.

FIG. 5 is a side view of the main part showing the tread forming apparatus 10 for the unvulcanized tread T described above, and shows a stage during the formation of the unvulcanized tread.
The tread forming apparatus 10 winds a strip-shaped unvulcanized tread T supplied from a supply means (not shown) around the BT drum 12 (1) to form an annular unvulcanized tread T. The BT drum 12 (1) is a cylindrical drum that can be expanded and contracted, and a plurality of (in the figure, 10 pieces) segments (sector-shaped divided pieces in side view) 13 that are disposed in a cylindrical shape in the circumferential direction of the drum. And an elastic band, for example, an elastic rubber band 14, which is disposed on the outer peripheral surface, that is, forms the outer peripheral surface of the BT drum 12 (1).
The BT drum 12 (1) includes a link connected to the segment 13, an expansion / contraction mechanism, and the like. Rotating means (each not shown).

FIG. 6 is a side view of the hoop ring 20 of the unvulcanized tread T and schematically shows the main part thereof.
As shown in the figure, the hoop ring 20 includes a cylindrical frame 21, a moving means 22 of the frame 21 fixed to the lower surface of the frame 21, and a plurality of divided holdings that are provided on the inner diameter portion of the frame 21 and can be expanded and contracted. Member 30. Further, the hoop ring 20 has expansion / contraction displacement means 23 that displaces and expands the plurality of divided holding members 30 synchronously and arranges them at a predetermined diameter position.

  The plurality of divided holding members 30 are divided into a plurality of portions in the circumferential direction and have an annular shape as a whole. The divided holding member is previously expanded or contracted to a position matched with the outer periphery of the unvulcanized tread T, and surrounds the unvulcanized tread T to hold the surface (the surface facing the unvulcanized tread T). Then, the unvulcanized tread T having an enlarged diameter is vacuum-adsorbed and held.

  By the way, if the tread elongation varies in the tire manufacturing process, the required thickness uniformity cannot be obtained, and the uniformity performance deteriorates. Generally, the tread thickness varies as follows: (i) When the unvulcanized tread T is wound around the BT drum 12 (1) and the BT drum 12 (1) is expanded, the expanded unvulcanized tread T is uniformly expanded on the circumference. If not possible, (ii) When holding the unvulcanized tread T having an enlarged diameter to be attached to the molded body H by the hoop ring 20, if (3) the unvulcanized tread T is not It is known that this occurs when the set is insufficient when set on the peripheral surface of the molded body H (in this case, it is caused by partial shrinkage due to the self-shrinking force of the unvulcanized tread). ing.

  Among the variations in the elongation of the unvulcanized tread T, the above (i) occurs at the earliest stage in the tire manufacturing process, so that the influence may extend to the above (ii) and (iii). Therefore, it is particularly important to prevent this, and there is a need for a solution.

Then, the reason why the elongation of the unvulcanized tread T varies due to the above (i) will be described.
First, the formation of the annular unvulcanized tread T in the tread forming apparatus 10 (see FIG. 5) will be described. In order to form the annular unvulcanized tread T, the BT drum 12 (1) is rotationally driven by a rotating means (not shown) and rotated around the axis at a predetermined speed. Cutting and winding the elastic rubber band 14 for one round (or cutting after winding), the rotation of the BT drum 12 (1) and the supply of the unvulcanized tread T are stopped. Subsequently, the end portions of the unvulcanized tread T are joined by an arbitrary end joining means. Subsequently, the plurality of segments 13 are displaced radially outward by the expansion / contraction means.

FIG. 7 is a side view of the BT drum when an annular unvulcanized tread is formed, FIG. 7A is a state before diameter expansion, FIG. 7B is a side view of the BT drum showing a state after diameter expansion, and FIG. These are side views which show a part of BT drum after diameter expansion.
In FIG. 7A, the elastic rubber band 14 is wound around the outer peripheral surface of a plurality of segments 13 having a fan-shaped cross section, and the inner peripheral surface is within the segment 13 within the range in which the BT drum 12 (1) can be expanded and contracted. It always abuts on the outer peripheral surface of the elastic member and elastically deforms. At this time, when the inner peripheral surface of the elastic rubber band 14 and the segment 13 are in close contact (see FIG. 7C), the deformation of the portion L1 that contacts the segment 13 is suppressed and it becomes difficult to extend. Greatly expands and deforms. In this case, the unvulcanized tread T is also affected by the deformation of the elastic rubber band 14 in contact with the inner peripheral surface, and expands and expands in the same manner as the elastic rubber band 14, and greatly expands and thins. The portions and the portions that extend slightly and have a small thickness change alternately occur along the circumferential direction. As a result, in the unvulcanized tread T, a thick portion and a thin portion are formed in order along the circumferential direction, and the thickness uniformity is reduced.

  Further, when the friction between the outer peripheral surface of the elastic rubber band 14 and the inner peripheral surface of the unvulcanized tread T is large and the outer peripheral surface of the elastic rubber band 14 and the inner peripheral surface of the unvulcanized tread T are in close contact, the segment 13 In the portion that receives pressure (the pressure of the jam machine), that is, the portion where the segment 13 abuts through the elastic rubber band 14 (joint portion), the two come into close contact with each other due to the pressure of the jam machine. Since the unvulcanized tread T sticks to the elastic rubber band 14 like a suction cup by the contraction force of T, there is a possibility that it cannot be formed into a predetermined radius shape.

  Further, when the elastic rubber band 14 and the unvulcanized tread T are in close contact with each other, the elastic rubber band 14 and the unvulcanized tread T do not peel off well when the BT drum is reduced in diameter in the subsequent process, and the hoop ring 20 There is also a possibility that it cannot be held uniformly on the circumference. In addition, if the hoop ring 20 cannot be held uniformly on the circumference, there is a risk that the unvulcanized tread will be insufficiently set when the unvulcanized tread is set on the molded body H, both of which vary in the thickness of the unvulcanized tread. Can be a factor that causes

JP 2007-76182 A

  The present invention has been made in view of the above-described conventional problems, and the object thereof is to adhere the elastic band to the tread and the segment when forming an unvulcanized tire, particularly when forming an unvulcanized tread. Is to suppress the variation in elongation occurring in the molded unvulcanized tread.

The present invention is a tire manufacturing apparatus for molding an unvulcanized tire by attaching an unvulcanized tread molded by a tread molding apparatus to an outer periphery of a molded body, and the tread molding apparatus is arranged in a drum circumferential direction. A plurality of segments that can be expanded and contracted, expansion and contraction means for expanding and contracting the segments, and an elastic band that is mounted on an outer peripheral surface of the plurality of segments and constitutes a peripheral surface of the drum, The tire manufacturing apparatus includes an outer peripheral surface having an uneven surface for preventing adhesion to an annular unvulcanized tread, and an inner peripheral surface that is a low friction processing surface that comes into contact with the plurality of segments.
The present invention relates to a tire manufacturing method in which an unvulcanized tread is bonded to the outer periphery of a molded body to form an unvulcanized tire, and the unvulcanized tread is an elastic material constituting an expansion / contraction surface of a drum that can be expanded and contracted The elastic band is formed by wrapping on a band, removing from the drum while maintaining the expanded diameter with the drum, releasing the expanded diameter, and affixing to the outer periphery of the molded body. A tire manufacturing method including an outer peripheral surface having an uneven surface for preventing adhesion to an unvulcanized tread, and an inner peripheral surface that is a low-friction processing surface that comes into contact with the plurality of segments.

  According to the present invention, it is possible to prevent the elastic band from coming into close contact with the unvulcanized tread and the segment when the unvulcanized tread is formed. Moreover, since adhesion between the elastic band and the tread and between the elastic band and the expansion / contraction segment can be prevented, variation in elongation generated in the unvulcanized tread to be formed can be significantly suppressed.

It is a lineblock diagram showing typically the tire manufacturing device of one embodiment of the present invention. FIG. 2A is a side developed sectional view of an elastic rubber band used in the tire manufacturing apparatus according to the present embodiment, FIG. 2A is a side sectional view showing the elastic rubber band and other members related thereto, and FIG. 2B is a side sectional view of the elastic rubber band. FIG. 2C is a plan view thereof. The horizontal axis is a position along the circumferential direction of the unvulcanized tread T, and the vertical axis is a graph showing the elongation ratio of the unvulcanized tread T after diameter expansion, showing the elongation ratio (%) at each position. 3A is an example in the case where the friction reducing treatment is not performed on the inner peripheral surface of the elastic rubber band, and FIG. 3B is a case where the inner peripheral surface of the elastic rubber band which is an embodiment of the present invention is subjected to rubber unevenness processing. It is the figure shown in comparison with what pasted the cloth which is the implementation goods. It is a figure which shows typically an example of the manufacturing process in the tire manufacturing method which manufactures a tire. It is a principal part side view which shows the tread formation apparatus of an unvulcanized tread, and has shown the formation middle stage of the unvulcanized tread. It is a side view of the unvulcanized tread hoop ring. FIG. 7A is a side view of a BT drum when an annular unvulcanized tread is formed, FIG. 7A is a side view before the diameter expansion, FIG. 7B is a side view of the BT drum showing a state after the diameter expansion, and FIG. It is a side view which shows a part of BT drum after a diameter.

Hereinafter, an embodiment of a tire manufacturing apparatus and a tire manufacturing method of the present invention will be described with reference to the drawings.
FIG. 1 is a configuration diagram schematically showing a tire manufacturing apparatus according to the present embodiment, which is basically the same as the conventional one already described with reference to FIG.
Here, the tire manufacturing apparatus will be described again. The tire manufacturing apparatus 1 includes an unvulcanized tread supply means 11, a molding drum 12 (2) for molding a molded body, and a BT drum 12 (1). A tread forming device 10 that forms a vulcanized tread, a hoop ring 20 that holds an unvulcanized tread after formation, and a stitching device 5 that includes a pair of pressing rollers 50 are provided.

The tire manufacturing apparatus 1 also has an arrangement means (not shown) for moving the hoop ring 20 and arranging the unvulcanized tread T adsorbed and held on the hoop ring 20 on the outer periphery of the molding drum 12 (2). The axes of the BT drum 12 (1) and the forming drum 12 (2) and the center axis of the hoop ring 20 are all located on the same center line CL.
Therefore, the hoop ring 20 moves concentrically with both the drums 12 (1) and 12 (2) along the center line CL in the direction of the arrow shown in the drawing. The above configuration is not particularly different from the conventional tire manufacturing apparatus already described.

Here, the configuration itself of the tread forming apparatus 10 is as described with reference to FIG. 5, but the elastic rubber band 14 used in this embodiment does not adhere to any of the segment 13 and the unvulcanized tread T. Thus, the structure is improved, which is different from the conventional structure.
Then, next, the elastic rubber band 14 of this embodiment is demonstrated.

FIG. 2 is a side developed sectional view of the elastic rubber band 14 used in the tire manufacturing apparatus according to the present embodiment, and FIG. 2A is an elastic rubber band 14 and its related members (segment and annular unvulcanized tread T). 2B is a side sectional view of the elastic rubber band, and FIG. 2C is a plan view thereof.
As shown in FIG. 2A, the elastic rubber band 14 has an unvulcanized tread T on its outer peripheral surface (upper surface in the drawing) side and an inner peripheral surface (in the drawing). The segments 13 are disposed in contact with the lower surface.

The outer peripheral surface serving as a contact surface with the unvulcanized tread T is formed on a minute uneven surface 14 (1) having a thread shape or a mesh shape in order to prevent adhesion with the unvulcanized tread T. A part of the outer peripheral surface of the elastic rubber band 14 is a stretchable fabric having a sliding resistance smaller than that of the elastic rubber band 14 main body instead of the uneven surface 14 (1). The elastic rubber band 14 main body of the elastic rubber band (for example, a stretchable cloth made of knitted cotton or polyethylene terephthalate (PET) fiber) divides the uneven surface 14 (1) in the circumferential direction. (14 (2)). Further, the inner peripheral surface of the elastic rubber band 14 is a low-friction treatment surface, that is, the same stretchable fabric as that of the elastic rubber band 14 whose sliding resistance with the segment 13 is small over the entire peripheral surface. The surface is affixed with fabric (14 (3)).
Although the inner peripheral surface of the elastic rubber band 14 can be a roughened surface similar to the outer peripheral surface, as is clear from the experimental results described later, the unvulcanized tread is less in comparison with the case of using fabric. The uniform elongation preventing effect is somewhat reduced.

Here, the uneven surface 14 (1) is formed by, for example, attaching a nylon mesh with a release agent to the outer peripheral surface of the elastic rubber band 14 and vulcanizing it while applying pressure. It is formed by peeling the nylon mesh after vulcanization.
Further, as shown in the figure, the elastic rubber band 14 has a through-hole 14a that penetrates from the cloth ground (back surface) 14 (3) to the outer circumferential uneven surface (front surface) 14 (1). Are provided at appropriate intervals along the circumference. In the illustrated example, the through holes 14a are provided in a line at the center in the width direction of the uneven surface 14 (1) of the elastic rubber band 14.

  In the present embodiment, since the outer peripheral surface of the elastic rubber band 14 is an uneven surface 14 (1), the unvulcanized tread T is wound around the BT drum 12 (1) on the elastic rubber band 14, and the BT drum 12 ( When the diameter of 1) is increased, the air is held in the uneven space of the uneven surface 14 (1), thereby preventing adhesion. Therefore, it can be easily peeled when the elastic rubber band 14 is reduced in diameter. (By the way, when fabric is pasted on the contact surface of the elastic rubber band 14 with the unvulcanized tread T, that is, on the outer peripheral surface thereof, air is removed. It cannot be held, and therefore, it cannot provide an adhesion prevention effect by air).

Here, the reason why the through-hole 14a is provided in the elastic rubber band 14 is that air is passed through the through-hole 14a from the inner peripheral surface side of the elastic rubber band 14 into the concavo-convex gap of the concavo-convex processed surface 14 (1) of the elastic rubber band 14. It is for making it flow in. That is, by providing the through hole 14a, the air retaining function on the uneven surface 14 (1) of the elastic rubber band 14 is reliably maintained. Therefore, the peeling effect can be obtained with certainty.
In addition, a part of the outer peripheral surface of the elastic rubber band 14 is used as the fabric 14 (2) because the joint force of the ring-shaped tread joint portion is improved, and the elastic rubber band 14 is connected to the inner periphery of the unvulcanized tread T. This is because it is easy to press the surface with a jam machine. The ease of pressure bonding is better than when the rubber material is processed to be uneven.
In addition, this fabric ground 14 (2) does not have the function to hold | maintain air, In that respect, like the said uneven | corrugated processed surface 14 (1), the elastic rubber band 14 and the unvulcanized tread T It does not improve the peelability.

  When the elastic rubber band 14 according to the present embodiment is used for the BT drum 12 (1), when the diameter of the segment 13 is increased, the elastic rubber band 14 and the unvulcanized tread T come into contact with each other and the elastic rubber band 14 The frictional resistance of the portion in contact with the segment 13 (all in the region of L1 (FIG. 7)) is reduced as compared with the case where the elastic rubber band 14 is formed of an unprocessed rubber material, and the members in contact with each other are easily slippery. . Therefore, the entire elastic rubber band 14 can be uniformly extended, and the unvulcanized tread T can be uniformly expanded in diameter while suppressing variations in elongation along the circumferential direction, and hence variations in thickness. I can let you. In addition, according to the present embodiment, since the release property of the elastic rubber band 14 with respect to the unvulcanized tread T is improved, the unvulcanized tread T is correctly held by the hoop ring 20. In the state where the uniformity of the thickness in the circumferential direction is increased, the thickness can be uniformly attached to the outer periphery of the molded body H.

  In this embodiment, the unvulcanized tread T is moved so as to be opposed to the outer periphery of the molded body H. However, the unvulcanized tread T is moved without moving the unvulcanized tread T. You may make it move to the inner peripheral side of T, and arrange | position them so that it may oppose.

(Experimental example)
FIG. 3 is a graph showing the elongation rate of the unvulcanized tread T after diameter expansion, where the horizontal axis indicates the position along the circumferential direction of the unvulcanized tread T, and the vertical axis indicates the elongation rate (%) at each position. Show.
FIG. 3A shows an example (comparative example) in which no particular friction reduction treatment is applied to the inner peripheral surface (referred to as the back surface) of the elastic rubber band, and FIG. , Mesh processing) (executed product 1) and a fabric (knitted) pasted (implemented product 2).
In the figure, the valley where the elongation is small is the part where the segment is in contact with the elastic rubber band (segment position), and the peak is the part where the segment is not in contact with the elastic rubber band (between the segments) ).
As shown in the drawing, in the comparative example, the difference R (%) in the elongation between the portion where the elastic rubber band 14 and the segment 13 are in contact and the portion where the elastic band 14 and the segment 13 are not in contact is significant, and the difference between 5.9% and 6.0%. There is. In the product 1, the difference R (%) in elongation between the portion where the elastic rubber band and the segment abut and the portion where the segment does not abut is 3.7% to 5.8%, which is an improvement over the comparative example. The effect is recognized.

On the other hand, in the product 2, the difference R (%) in elongation between the portion where the elastic rubber band and the segment abut and the portion where the segment does not abut is 2.4% to 2.7%. On the other hand, of course, a remarkable improvement effect is recognized also with respect to the implementation product 1 which has been subjected to the uneven processing.
From this comparison result, as a matter of course, for the comparative example in which no friction reducing treatment was performed on the inner peripheral surface of the elastic rubber band, the inner peripheral surface of the elastic rubber band, that is, the contact surface side with the segment, was subjected to uneven processing Even with respect to the applied product 1, the elastic rubber band having the inner peripheral surface of the implemented product 2 as the fabric surface is evenly extended, and the thickness of the unvulcanized tread T is highly uniform in the circumferential direction. Prove that you can.

  DESCRIPTION OF SYMBOLS 1 ... Tire manufacturing apparatus, 5 ... Stitching apparatus, 50 ... Pressure roller, 10 ... Tread formation apparatus, 11 ... Supply means of unvulcanized tread, 12 (1) ... BT drum, 12 (2) ... molding drum, 13 ... segment, 14 ... elastic rubber band, 20 ... hoop ring, 21 ... frame, 22 ... moving means, 23 ... -Expansion / contraction displacement means, 30 ... split holding member, T ... unvulcanized tread.

Claims (7)

A tire manufacturing apparatus for molding an unvulcanized tire by attaching an unvulcanized tread molded by a tread molding apparatus to an outer periphery of a molded body,
The tread forming apparatus includes a plurality of segments that can be expanded and contracted arranged in a drum circumferential direction, a scaling unit that expands and contracts the segments, and a peripheral surface of the drum that is mounted on an outer peripheral surface of the plurality of segments. And an elastic band that
The said elastic band is a tire manufacturing apparatus provided with the outer peripheral surface provided with the uneven | corrugated processed surface for contact | adherence prevention with a cyclic | annular unvulcanized tread, and the inner peripheral surface which is a low friction process surface contact | abutted with these segments. In the tire manufacturing apparatus according to claim 1,
The tire manufacturing apparatus, wherein the inner peripheral surface is a stretchable cloth ground affixed to an elastic band. In the tire manufacturing apparatus according to claim 1 or 2,
The uneven manufacturing surface for preventing adhesion is a tire manufacturing apparatus that is a yarn processed surface or a stitch processed surface. In the tire manufacturing apparatus according to claim 2 or 3,
The said elastic band is a tire manufacturing apparatus which has a through-hole penetrated from the fabric surface of the said inner peripheral side to the uneven | corrugated processed surface of the said outer peripheral side. In the tire manufacturing apparatus according to any one of claims 1 to 4,
A tire manufacturing apparatus in which a part of the outer peripheral surface of the elastic band is formed of a fabric. A tire manufacturing method in which an unvulcanized tread is attached to the outer periphery of a molded body to form an unvulcanized tire,
The unvulcanized tread is formed by wrapping on an elastic band constituting an expansion / contraction surface of a drum that can be expanded / contracted, and is removed from the drum while maintaining the expansion by the drum. It has each process stuck on the outer periphery,
The elastic band includes an outer peripheral surface having an uneven surface for preventing adhesion to an annular unvulcanized tread, and an inner peripheral surface that is a low friction processing surface that comes into contact with the plurality of segments. Production method. In the tire manufacturing method according to claim 6,
The uneven surface is a tire manufacturing method in which a rubber material to be an elastic band and a mesh member are stacked and pressurized and vulcanized, and the mesh member is peeled from the rubber material after vulcanization.

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