JP2020100117A - Mouthpiece for extrusion molding - Google Patents

Abstract

To provide a mouthpiece for extrusion molding that improves durability and prevents molding defects in strip rubber.SOLUTION: A mouthpiece 10 for extrusion molding is attached to the tip of an extruder 4. The mouthpiece 10 for extrusion molding is made of a rubber material fed from a main body 7 of the extruder 4 into a strip of rubber 3. It has an aperture 16 that is extruded, and a hardening section 17 is provided in a predetermined area around the periphery of the aperture 16.SELECTED DRAWING: Figure 3

Description

The present invention relates to an extrusion die.

Conventionally, as a method for manufacturing a pneumatic tire, a strip-shaped strip rubber extruded from a die attached to the tip of an extruder is spirally wound around a drum to form a green tire. A ribbon method is known (see Patent Document 1, for example).

The extrusion die used when, for example, extruding a strip rubber for forming a green tire by the ribbon method is generally made of a steel material. As an extrusion molding die, one having a surface plated with chromium is also known (see, for example, Patent Document 2).

JP, 2008-103516, A JP-A-9-225989

As shown in FIG. 8(a), the strip-shaped strip rubber used when manufacturing the pneumatic tire by the ribbon method has a flat shape corresponding to the cross-sectional shape of the strip rubber on the die 100 attached to the tip of the extruder. It is extruded through the formed opening 110.

As shown in FIG. 8B, when the die 100 is extruded and the strip rubber is extruded, as shown in FIG. 8B, the peripheral edges on both sides of the opening 110 are worn from the upstream side in the extruding direction and are opened to form the strip rubber. Molding defects may occur. Therefore, when the peripheral portion of the opening of the die is worn, it is necessary to replace the die with a new one, which may cause a decrease in productivity.

On the other hand, it is conceivable to improve the durability of the die by plating the die with chrome as described in Patent Document 2. However, when chrome plating is applied to the die, the chrome plating may be peeled off and mixed into the strip rubber to cause defective molding.

Therefore, it is an object of the present invention to provide an extrusion-molding die capable of improving the durability and suppressing the occurrence of molding defects in the strip rubber.

The present invention is an extrusion molding die attached to the tip of an extruder, comprising an opening for extruding a rubber material supplied from the main body of the extruder as a strip-shaped strip rubber. Provided is an extrusion molding die in which a quenching portion is provided in a predetermined region of a peripheral portion.

According to the present invention, the extrusion die has a quenching portion provided in a predetermined region of the peripheral portion of the opening for extruding a rubber material as a strip rubber to suppress abrasion of the peripheral portion of the opening portion for extrusion molding. It is possible to improve the durability of the die and suppress the occurrence of molding defects in the strip rubber. Since the quenching portion is provided in a predetermined region of the peripheral portion of the opening of the extrusion-molding die, it suppresses the occurrence of cracking and suppresses the occurrence of cracks as compared with the case where the extrusion-molding die is entirely quenched. The durability of can be improved.

It is preferable that the quenching portion is provided on the peripheral portion of the opening on the main body side of the extruder.

According to this configuration, since the quenching portion is provided in the peripheral edge portion of the opening on the main body side of the extruder where abrasion is more likely to occur than on the side opposite to the main body side of the extruder, the opening of the extrusion die It is possible to effectively suppress the wear of the peripheral portion.

It is preferable that the opening has a flat cross-sectional shape whose height is smaller than the width, and the quenching section is provided on both sides in the width direction of the opening on the main body side of the extruder. ..

According to this configuration, since the quenching portions are provided at the peripheral portions on both sides in the width direction of the opening where abrasion is more likely to occur than the peripheral portion on the center side in the width direction of the opening, the opening of the die for extrusion molding is It is possible to effectively suppress the wear of the peripheral portion.

It is preferable that the quenching portion is provided on the entire peripheral portion of the opening on the main body side of the extruder.

According to this configuration, it is possible to suppress the abrasion of the entire peripheral portion of the opening of the extrusion-molding die, improve the durability of the extrusion-molding die, and suppress the occurrence of molding failure in the strip rubber.

The opening has a flat rectangular, triangular, or trapezoidal cross-sectional shape whose height is smaller than its width.

According to this configuration, when a strip rubber having a flat rectangular shape, a triangular shape, or a trapezoidal cross-sectional shape whose height is smaller than its width is extruded, it is possible to suppress the occurrence of molding defects in the strip rubber. be able to.

The extrusion die is preferably an extrusion die for extruding a strip rubber forming a green tire.

According to this configuration, when the strip rubber extruded from the extrusion die is spirally overlapped and wound to form a green tire, it is possible to suppress the occurrence of molding failure in the strip rubber and spiral the strip rubber. It is possible to prevent air from entering between the strip rubbers when the sheets are overlapped and wound.

According to the extrusion molding die according to the present invention, it is possible to improve the durability and suppress the occurrence of molding failure in the strip rubber.

It is a schematic block diagram of the winding device which has an extruder provided with the die for extrusion molding which concerns on 1st Embodiment of this invention. It is sectional drawing which shows the winding state of the strip rubber wound around a drum. It is a sectional view of a die for extrusion molding. It is a rear view of a die for extrusion molding. It is a rear view of the modification of the die for extrusion molding concerning a 1st embodiment of the present invention. It is a rear view of the die for extrusion molding concerning a 2nd embodiment of the present invention. It is a rear view of the die for extrusion molding concerning a 3rd embodiment of the present invention. It is a figure which shows the opening vicinity of the conventional extrusion die.

Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings.

FIG. 1 is a schematic configuration diagram of a winding device having an extruder including an extrusion molding die according to a first embodiment of the present invention. As shown in FIG. 1, a winding device 1 having an extruder equipped with an extrusion molding die according to a first embodiment of the present invention forms a green tire which is a raw tire before vulcanization molding by a ribbon method. It is sometimes used.

The winding device 1 includes a drum 2 that is formed into a substantially cylindrical shape and is driven to rotate, an extruder 4 that extrudes a strip-shaped strip rubber 3 that is supplied to the drum 2, and a strip rubber 3 that is supplied to the drum 2. It is provided with a pressure bonding roller 5 which is pressed against the drum 2 and attached.

The strip rubber 3 has a flat cross-sectional shape whose height (thickness) is smaller than its width and is formed in a band shape. The strip rubber 3 is formed so that the width of the cross-sectional shape is 10 to 50 mm and the cross-sectional height is 0.6 to 3 mm, for example.

The drum 2 is held by a drum holding device 6. The drum 2 is configured to be rotationally driven by the drum holding device 6 and movable in the axial direction of the drum 2. The drum 2 is rotationally driven such that the side facing the extruder 4 is from the bottom to the top, and for example, the sticking speed of the strip rubber 3 stuck to the surface is 5 to 130 m/min.

The extruder 4 heats a rubber material by a screw and a heater which are driven to rotate, and kneads and kneads the rubber material to supply it to the tip portion, and the extruder 4 which is attached to the tip portion of the extruder 4 to feed the material. And an extrusion molding die 10 for extruding a strip-shaped strip rubber 3 from the rubber material. The extruder 4 heats the rubber material to a temperature at which the strip rubber 3 is not vulcanized, for example, a temperature of 120 degrees or less.

The pressure roller 5 is rotatably attached to the tip of a rod 9 that extends from the cylinder 8 so as to expand and contract. The pressure bonding roller 5 is brought into contact with and separated from the drum 2 in a state where the rotation axis is parallel to the rotation axis of the drum 2, and the strip rubber 3 is wound around the drum 2 to be attached and pressure-bonded.

In the winding device 1, when the strip rubber 3 extruded and molded by the extruder 4 is advanced toward the drum 2 and is pressed by the pressure bonding roller 5 and wound around the drum 2, the drum 2 is moved in the axial direction. Then, the strip rubber 3 is spirally wound around the drum 2 to form a green tire.

FIG. 2 is a cross-sectional view showing a wound state of the strip rubber wound around the drum. As shown in FIG. 2, the strip rubber 3 is spirally wound around the drum 2 so that both sides in the width direction overlap each other. The green tire GT is formed by spirally winding the strip rubber 3. The green tire GT is also combined with other tire constituent members. Then, the green tire GT is vulcanized and molded to manufacture a pneumatic tire.

When the strip rubber 3 is spirally wound around the drum 2, depending on the desired shape of the green tire GT, the strip rubber 3 may be further wound around the strip rubber 3 previously wound around the drum 2. Good. Further, instead of moving the drum 2 in the axial direction, the extruder 4 and the pressure bonding roller 5 may be moved in the axial direction.

Next, the extrusion die according to the embodiment of the present invention will be described.
FIG. 3 is a sectional view of the extrusion-molding die, and FIG. 4 is a rear view of the extrusion-molding die. 4 shows the extrusion die as viewed from the main body of the extruder, and FIG. 3 shows a cross section of the extrusion die along the line Y3-Y3 in FIG. As shown in FIGS. 3 and 4, an extrusion molding die (hereinafter, appropriately referred to as a “die”) 10 is provided so as to protrude from the main body portion 7 of the extruder 4 in a substantially truncated cone shape.

The mouthpiece 10 includes a flange portion 11 attached to the main body portion 7 of the extruder 4, a side surface portion 12 formed in a tapered cylindrical shape from the inside of the flange portion 11 in the radial direction toward the main body portion side, and an opposite side surface of the side surface portion 12. And a top surface portion 13 that extends radially inward from the main body portion side. The top surface portion 13 of the die 10 has a surface 13 a on the main body side of the extruder 4 and a surface 13 b on the opposite main body side of the extruder 4. The mouthpiece 10 has an opening 16 on the top surface 13 for extrusion-molding a rubber material supplied from the main body 7 of the extruder 4 as a strip-shaped strip rubber 3. The opening 16 is formed so as to penetrate the die 10 from the surface 13a on the main body side of the extruder 4 to the surface 13b on the opposite main body side.

The opening 16 of the base 10 is formed so as to correspond to the desired sectional shape of the strip rubber 3. In the present embodiment, the opening 16 of the mouthpiece 10 has the same cross-sectional shape in the extrusion direction of the strip rubber 3, and has a flat, substantially triangular cross section in which the height H1 is smaller than the width W1 as shown in FIG. It has a shape. Through the opening 16 of the mouthpiece 10, the strip rubber 3 having a flat and substantially triangular cross-sectional shape whose height is smaller than its width is extruded. The opening 16 of the base 10 can be formed in any other triangular shape, not limited to the isosceles triangular shape shown in FIG. 4, as long as the opening 16 has a flat shape with a small height with respect to the width.

The die 10 is made of a hardenable steel material. As shown by cross-hatching in FIGS. 3 and 4, the die 10 is provided with a quenching portion 17 that is quenched in a predetermined region of the peripheral portion of the opening 16 on the main body 7 side of the extruder 4.

The quenching portion 17 of the die 10 is provided on the entire peripheral edge portion of the opening 16 including the peripheral portions on both sides in the width direction of the opening 16 on the main body 7 side of the extruder 4 of the die 10. As shown in FIG. 3, the quenching portion 17 has a predetermined width L1 outside the opening 16 at the peripheral portion of the opening 16 of the die 10, and from the surface 13a of the extruder 4 on the side of the main body 7 to the extruder 4. It is formed so as to have a predetermined depth D1 toward the surface 13b side on the side opposite to the main body portion. In the present embodiment, the quenching portion 17 is not provided on the side of the main body portion opposite the extruder 4, and the surface 13b of the side of the extruder 4 opposite the main body portion is not quenched. The width L1 of the hardened portion 17 is set to, for example, 2 to 5 mm, and the depth D1 of the hardened portion 17 is set to, for example, 3 mm or less. The width L1 of the hardened portion 17 may be set to, for example, 150 to 700% of the height H1 of the opening 16.

In the die 10, the hardened portion 17 has a higher hardness than the non-hardened portion 18 which is not hardened. The quenching portion 17 of the die 10 is formed by quenching under predetermined quenching conditions, heating to a quenching temperature, and then cooling. The quenching portion 17 of the die 10 is also tempered after quenching under a predetermined tempering condition, heated to a temperature lower than the quenching temperature, and then cooled.

Although the die 10 is not limited to this, in the present embodiment, it is formed from die steel SKD11, and the quenching portion 17 is air-cooled after being heated to 1000 to 1050 degrees as quenching conditions, for example. As a tempering condition, it is heated to 150 to 200 degrees and then air-cooled. The quenching unit 17 is heated by using a heating device such as a laser heating device or an induction heating device. In this way, the die 10 is formed so that, for example, the non-quenched portion 18 of the die 10 has a hardness of 34 to 42 Hs, while the hardened portion 17 has a hardness of 62 to 78 Hs.

The quenching portion 17 of the die 10 is provided so as to have a predetermined depth D1 from the surface 13a on the main body portion 7 side of the extruder 4 to the surface 13b on the opposite main body portion side of the extruder 4. It may be provided from the surface 13a on the main body portion 7 side to the surface 13b on the opposite main body portion side of the extruder 4.

As described above, the extrusion-molding die 10 according to the present embodiment is attached to the tip of the extruder 4, and is an opening for extruding the rubber material supplied from the main body portion 7 of the extruder 4 as the strip-shaped strip rubber 3. The portion 16 is provided, and the quenching portion 17 is provided in a predetermined region of the peripheral portion of the opening 16.

As a result, the extrusion die 10 suppresses abrasion of the peripheral edge of the opening 16 by the quenching portion 17 provided in a predetermined region of the peripheral edge of the opening 16 for extruding the rubber material as the strip rubber 3, and extrudes the extrusion. It is possible to improve the durability of the molding die 10 and suppress the occurrence of molding failure in the strip rubber 3. Since the quenching portion 17 is provided in a predetermined region of the peripheral portion of the opening 16 of the extrusion die 10, the occurrence of cracks is suppressed as compared with the case where the extrusion die 10 is entirely quenched. The durability of the extrusion molding die 10 can be improved.

Further, the quenching portion 17 is provided on the peripheral portion of the opening 16 on the main body portion 7 side of the extruder 4. As a result, the quenching portion 17 is provided at the peripheral edge portion of the opening 16 on the main body portion 7 side of the extruder 4 where abrasion is more likely to occur than on the opposite main body portion side of the extruder 4. Wear of the peripheral portion of the opening 16 can be effectively suppressed.

In addition, the opening 16 has a flat cross-sectional shape whose height is smaller than its width, and the quenching portions 17 are provided on both sides in the width direction of the opening 16 on the main body 7 side of the extruder 4. .. As a result, the quenching portions 17 are provided at the peripheral edge portions on both sides in the width direction of the opening portion 16 that are more likely to be worn than the peripheral edge portion on the center side in the width direction of the opening portion 16. It is possible to effectively suppress the wear of the peripheral portion of 16.

Further, the quenching portion 17 is provided on the entire periphery of the opening 16 on the main body 7 side of the extruder 4. As a result, it is possible to suppress the abrasion of the entire peripheral portion of the opening 16 of the extrusion molding die 10 to improve the durability of the extrusion molding die 10 and to prevent the strip rubber 3 from being defective. ..

The opening 16 has a flat triangular cross-sectional shape whose height is smaller than its width. This makes it possible to prevent defective molding of the strip rubber 3 when the strip rubber 3 having a flat triangular cross-sectional shape having a smaller height than the width is extrusion-molded.

The extrusion-molding die 10 is an extrusion-molding die 10 that extrudes the strip rubber 3 that forms the green tire GT. Thus, when the strip rubber 3 extruded from the extrusion die 10 is spirally overlapped and wound to form the green tire GT, it is possible to prevent the strip rubber 3 from being defective and to prevent the strip rubber 3 from being defective. It is possible to prevent air from entering between the strip rubbers 3 when the sheets are spirally overlapped and wound.

FIG. 5 is a rear view of a modified example of the extrusion molding die according to the first embodiment of the present invention. As shown by cross-hatching in FIG. 5, the quenching portion 17 ′ of the extrusion-molding die 10 can be provided only on the peripheral portions on both sides in the width direction of the opening 16 on the main body portion 7 side of the extruder 4. Also in the quenching section 17', a predetermined depth is provided from the surface of the extruder 4 on the main body 7 side to the surface of the extruder 4 on the side opposite to the main body, or the surface of the extruder 4 on the main body side. To the surface of the extruder 4 on the side opposite to the main body portion.

FIG. 6 is a rear view of the extrusion die according to the second embodiment of the present invention. The extrusion-molding die 30 according to the second embodiment is the same as the extrusion-molding die 10 according to the first embodiment except that the shape of the opening is different, and thus the description of the same configuration is omitted.

Also in the extrusion-molding die 30 according to the second embodiment, an opening portion 36 attached to the tip of the extruder 4 and extruding a rubber material supplied from the main body portion 7 of the extruder 4 as the strip-shaped strip rubber 3 is formed. Equipped with. In this embodiment, as shown in FIG. 6, the opening 36 of the mouthpiece 30 is formed in a flat, substantially rectangular cross-sectional shape whose height is smaller than its width.

The die 30 is also provided with a quenched portion 37 in a predetermined region of the peripheral portion of the opening 36 on the main body 7 side of the extruder 4, and the quenched portion 37 is the unquenched portion 18 of the die 30 that has not been quenched. The hardness is increased. The quenching portion 37 of the die 30 is provided on the entire periphery of the opening 36 including both sides in the width direction of the opening 36 on the body 7 side of the extruder 4 of the die 30, and the surface of the extruder 4 on the body 7 side. Is provided so as to have a predetermined depth from the surface of the extruder 4 toward the surface opposite to the main body.

The quenching portion 37 of the die 30 may be provided only on both sides in the width direction of the opening 36 on the body 7 side of the extruder 4 of the die 30. The quenching portion 37 of the die 30 may also be provided from the surface 13a of the extruder 4 on the main body 7 side to the surface 13b on the opposite main body side of the extruder 4.

As described above, also in the extrusion die 30 according to the present embodiment, the peripheral portion of the opening portion 36 is formed by the quenching portion 37 provided in a predetermined region of the peripheral portion of the opening portion 36 for extruding a rubber material as the strip rubber 3. It is possible to suppress the wear of the strip rubber 3 to improve the durability of the extrusion die 30, and to prevent the strip rubber 3 from being defective.

Further, the opening 36 of the base 30 has a flat rectangular cross-sectional shape whose height is smaller than its width. Thereby, when the strip rubber 3 having a flat rectangular cross-sectional shape whose height is smaller than its width is extrusion-molded, it is possible to suppress the molding failure of the strip rubber 3 from occurring.

FIG. 7 is a rear view of the extrusion die according to the third embodiment of the present invention. The extrusion-molding die 40 according to the third embodiment is the same as the extrusion-molding die 10 according to the first embodiment except that the shape of the opening is different, and thus the description of the same configuration will be omitted.

Also in the extrusion molding die 40 according to the third embodiment, an opening portion 46 that is attached to the tip end portion of the extruder 4 and extrusion-molds the rubber material supplied from the main body portion 7 of the extruder 4 as the strip-shaped strip rubber 3. Equipped with. In the present embodiment, as shown in FIG. 7, the opening 46 of the base 40 is formed in a flat, substantially trapezoidal cross-sectional shape whose height is smaller than its width.

Also in the die 40, a quenched portion 47 is provided in a predetermined region of the peripheral portion of the opening 46 on the main body 7 side of the extruder 4, and the quenched portion 47 is a non-quenched portion 18 of the die 40 which is not quenched. The hardness is increased. The quenching portion 47 of the die 40 is provided on the entire peripheral portion of the opening 46 including the peripheral portions on both sides in the width direction of the opening 46 on the body portion 7 side of the extruder 4 of the die 40, and the body portion 7 of the extruder 4 is provided. It is provided so as to have a predetermined depth from the surface on the side toward the surface on the side opposite to the main body of the extruder 4.

The quenching portion 47 of the die 40 may be provided only on both sides in the width direction of the opening 46 on the body portion 7 side of the extruder 4 of the die 40. The quenching portion 47 of the die 40 may also be provided from the surface 13a of the extruder 4 on the main body 7 side to the surface 13b on the opposite main body side of the extruder 4.

As described above, also in the extrusion die 40 according to the present embodiment, the peripheral edge portion of the opening portion 46 is formed by the quenching portion 47 provided in the predetermined region of the peripheral edge portion of the opening portion 46 for extruding the rubber material as the strip rubber 3. Of the extrusion molding die 40 to improve the durability of the extrusion molding die 40 and suppress the occurrence of molding failure in the strip rubber 3.

Further, the opening 46 of the base 40 has a flat trapezoidal cross-sectional shape whose height is smaller than its width. Accordingly, when the strip rubber 3 having a flat trapezoidal cross-sectional shape whose height is smaller than its width is extrusion-molded, it is possible to suppress the molding failure of the strip rubber 3 from occurring.

In each of the first and third embodiments, when the openings 16 and 46 having a flat triangular shape or a trapezoidal cross-sectional shape whose height is smaller than the width are formed in the mouthpieces 10 and 40, respectively, Hardened portions may be provided only on both sides in the width direction of the openings 16 and 46 and only on the peripheral portions on the side of the upper surfaces 16a and 46a.

In the above-described embodiment, the openings 16, 36, 46 of the mouthpieces 10, 30, 40 have a flat rectangular shape, a triangular shape, or a trapezoidal cross-sectional shape whose height is smaller than its width. Alternatively, it may have another cross-sectional shape such as another flat cross-sectional shape whose height is smaller than its width. Also in this case, the die 10, 30, 40 is provided with the quenching portions 17, 37, 47 in the predetermined regions of the peripheral portions of the openings 16, 36, 46 on the main body 7 side of the extruder 4.

The present invention is not limited to the illustrated embodiments, and various improvements and design changes can be made without departing from the gist of the present invention.

1 Winding Device 2 Drum 3 Strip Rubber 4 Extruder 5 Crimping Roller 7 Extruder Main Body 10, 30, 40 Mouth 16, 36, 46 Opening 17, 17', 37, 47 Quenching GT Green Tire

Claims (6)

An extrusion molding die attached to the tip of an extruder,
An extrusion-molding die comprising an opening for extruding a rubber material supplied from the main body of the extruder as a strip-shaped strip rubber, and a quenching part provided in a predetermined region of a peripheral portion of the opening. The extrusion-molding die according to claim 1, wherein the quenching portion is provided at a peripheral portion of the opening portion on the main body side of the extruder. The opening has a flat cross-sectional shape whose height is smaller than its width,
The extrusion-molding die according to claim 1 or 2, wherein the quenching portion is provided at peripheral portions on both sides in the width direction of the opening portion on the main body portion side of the extruder. The extrusion-molding die according to claim 3, wherein the quenching portion is provided on the entire periphery of the opening on the main body side of the extruder. The extrusion-molding die according to any one of claims 1 to 4, wherein the opening has a flat rectangular shape, a triangular shape, or a trapezoidal cross-sectional shape whose height is smaller than its width. .. The extrusion-molding die according to any one of claims 1 to 5, wherein the extrusion-molding die is an extrusion-molding die that extrudes the strip rubber that forms a green tire.

Images