JP4866097B2 - Rubber component manufacturing method for tire and rubber extrusion device used therefor - Google Patents

Description

  The present invention provides a strip wind method in which a rubber component of a tire is formed by spirally winding an unvulcanized rubber strip, and a plurality of rubber components having different rubber compositions are provided with an air pool between the rubber components. A method of manufacturing a rubber component of a tire that can be efficiently formed while being suppressed.

  For example, a so-called strip wind method in which at least one rubber component of a tire in each part such as tread rubber, sidewall rubber, clinch rubber, inner liner rubber, and bead apex rubber is spirally wound with an unadded rubber strip ( (Hereinafter referred to as STW method if necessary) has been proposed (see, for example, Patent Documents 1 to 3). In this STW method, the use of a large rubber extruder is eliminated, so that the factory equipment can be reduced in size, and the rubber extruder base change and adjustment work, etc., which are necessary for every tire size and product type change are not required. Especially in the tire industry, where there is a strong tendency for high-mix low-volume production, it has significant advantages.

  In order to obtain more merits of the STW method, for example, as shown in FIG. 9A, in the green tire molding process, a plurality of adjacent rubber constituent portions g are formed by the STW method. ing. FIG. 9A shows a case where the sidewall rubber g2 and the clinch rubber g3 are formed by the STW method, and the inner liner rubber g4 is formed in a sheet shape by a rolling method using a conventional calendar machine. Yes. Reference symbol a indicates a carcass ply, and reference symbol b indicates a bead core.

  In such a case, conventionally, a plurality of types (two types in this example) of rubber strips s2 and s3 having different rubber blends in accordance with the required characteristics of the respective rubber components g2 and g3 are extruded from the respective rubber extruders. At the same time, as shown in FIG. 9 (B), the rubber strips s2 and s3 are supplied to the molding drum d through the applicators c2 and c3 of the individual strip guide devices, and wound. The constituent parts g2 and g3 are formed.

Japanese Patent Laid-Open No. 2000-94542 Japanese Patent Laid-Open No. 2002-160508 Japanese Patent Laid-Open No. 2002-79590

  However, in such a conventional method, since it is necessary to install a plurality of applicators corresponding to the number of types of rubber strips around one molding drum, the equipment structure becomes complicated and the equipment space increases and the equipment There is a problem of increasing the cost. Further, since a gap is formed between the winding end portion of one rubber strip s2 and the winding start end portion of the other rubber strip s3, an air pool is generated between the formed rubber constituent portions g2 and g3. This easily increases the risk of tire quality degradation.

  Therefore, the present invention adopts a longitudinally-joined strip in which a plurality of types of strip zones having different rubber compositions are cascaded in the length direction as the rubber strip, and each rubber component is formed by a winding portion of each strip zone. Basically, the equipment structure can be simplified, such as the number of applicators used can be minimized, equipment space and equipment costs can be reduced, and the occurrence of air accumulation between rubber components can be suppressed, improving tire quality. An object of the present invention is to provide a method for producing a tire rubber component that can be improved, and a rubber extrusion device used therefor.

In order to achieve the above object, the invention of claim 1 of the present application is a tire rubber component manufacturing method for manufacturing a tire rubber component by winding an unvulcanized rubber strip spirally,
A rubber extrusion device continuously extrudes the rubber strip as a longitudinal strip in which a plurality of types of strip zones different in rubber composition are longitudinally connected,
According to each strip zone having a different rubber composition, the rubber component having a different tire is formed by winding the strip zone ,
The rubber extruding device comprises a plurality of rubber extruding machine bodies,
Between the rubber compositions from the plurality of rubber extruder bodies, by connecting the next rubber composition to the rear end of the preceding rubber composition using a switching valve,
The longitudinal strip is extruded from a discharge port of the rubber extrusion device .

The invention of claim 2 is a device for extruding a longitudinal strip rubber used in claim 1,
A plurality of rubber extruder bodies for extruding rubber compositions having different rubber compositions from the extrusion ports,
And a plurality of individual rubber passages for guiding the rubber composition from each of the extrusion ports to the downstream side, a selection chamber that communicates with the plurality of individual rubber passages, a downstream passage extending from the selection chamber, and a downstream end thereof And having an extrusion head having a discharge port located at
The extrusion head includes a switching valve that selectively switches between the downstream flow path and the plurality of individual rubber flow paths in the selection chamber.
By switching the switching valve, a plurality of rubber compositions from the extrusion port are sequentially selected and continuously sent out from the discharge port through the downstream flow path, thereby extending the strip zone made of each rubber composition. It is characterized by extruding as a longitudinally connected strip.
The invention according to claim 3 is characterized in that the switching valve is a ball valve.
According to a fourth aspect of the present invention, the extrusion head includes a rubber discharge amount control means having a gear pump in each of the individual rubber flow paths.

  As described above, the present invention continuously extrudes a longitudinal strip obtained by longitudinally cascading a plurality of types of strip zones having different rubber blends from one rubber extrusion device, and wraps the longitudinal strip in a spiral shape. Thus, different rubber components are sequentially formed by the winding portions of the strip zones having different rubber compositions.

  Accordingly, the number of applicators installed around the molding drum can be reduced to the minimum, the equipment structure for producing the raw tire can be simplified, and the equipment space and equipment cost can be reduced. In addition, when forming each rubber component, since there is no break in the strip, it is possible to suppress the occurrence of air accumulation, particularly at the joint between the rubber components, and the tire can be formed with high quality and efficiency. Become.

  Hereinafter, an embodiment of the present invention will be described with reference to the drawings. FIG. 1 is a cross-sectional view showing an example of a pneumatic tire formed including a rubber component manufactured by the manufacturing method of the present invention.

  In FIG. 1, a pneumatic tire 1 includes a cord reinforcing layer including a rubber component G of a plurality of tires having different rubber compositions, a carcass 6 that forms a skeleton of the tire, and a belt 7 that is disposed radially outward. It is formed with a cord reinforcement component J.

  In the cord reinforcing component J, the carcass 6 includes one or more carcass plies 6A in this example, in which carcass cords are arranged at an angle of, for example, 70 to 90 ° with respect to the tire circumferential direction. In this example, the carcass ply 6A includes ply folding portions 6b that are folded around the bead core 5 on both sides of the ply main body portion 6a that extends from the tread portion 2 through the sidewall portion 3 to the bead core 5 of the bead portion 4. In a series.

  The belt 7 includes two or more belt plies 7A and 7B in which belt cords are arranged at an angle of, for example, 10 to 35 ° with respect to the tire circumferential direction. In this example, the belt cords are alternately arranged between the plies. By intersecting, the belt rigidity is increased and the tread portion 2 is reinforced strongly. A band (not shown) in which band cords are arranged along the tire circumferential direction can be provided outside the belt 7 mainly for the purpose of improving high-speed running performance.

  Next, as the rubber component G, a tread rubber G1 disposed on the tread 2 and forming a ground contact surface, a sidewall rubber G2 disposed on the sidewall 3 and forming a tire outer surface, and the bead 4 A clinch rubber G3 that prevents the rim from being displaced, an inner liner rubber G4 that is disposed inside the carcass 6 and forms a tire cavity surface, and a bead apex rubber G5 that extends radially outward from the bead core 5. Can do. If the tread rubber G1 has a two-layer structure of the cap rubber part G1a on the grounding surface side and the base rubber part G1b on the radially inner side as in this example, the rubber parts G1a and G1b are also respectively It can be considered as a different rubber component.

  And at the time of green tire formation, at least 2 rubber component which adjoins mutually among the said rubber components G1-G5 is manufactured with the manufacturing method of this invention. In this example, the case where the sidewall rubber (rubber component) G2 and the clinch rubber (rubber component) G3 are manufactured by the manufacturing method of the present invention is illustrated.

  Specifically, as shown in FIG. 2, in this example, which is a cylindrical body D, an unvulcanized rubber strip 10 is spirally wound around a forming drum. The spiral winding may be performed by moving the rubber strip 10 in the axial direction of the wound body D while rotating the wound body D in accordance with the STW method. As shown in FIG. 3, the rubber strip 10 has a substantially rectangular shape having a width W of 5 to 30 mm, a thickness T of 0.5 to 3.0 mm, and a ratio T / W to the width W of 0.25 or less. A cross section is preferably employed.

  In the present invention, as the rubber strip 10, a plurality of types of strip zones 11 having different rubber blends, in this example, a single longitudinal strip 12 in which two types of strip zones 11A and 11B are cascaded in the length direction are used. To do. Then, the longitudinal strip 12 is spirally adjusted while appropriately adjusting the lengths of the strip bands 11A and 11B and the requirements for spiral winding (for example, the rotational speed of the wound body and the lateral movement speed of the strip). Wrap. Thereby, the side wall rubber (rubber component) G2 is wound by the winding portion where the strip zone 11A is wound, and the clinch rubber (rubber component) G3 is wound by the winding portion where the strip zone 11B is wound. They can be formed sequentially and continuously.

  In this way, since the longitudinal strip 12 is used, it is between the rear end of the strip zone 11A that forms the sidewall rubber (rubber component) G2 and the front end of the strip zone 11A that forms the clinch rubber (rubber component) G3. In addition, there is no possibility that a stepped discontinuity will occur. Therefore, it is possible to suppress the occurrence of air pockets due to the interrupted portion. Further, after the formation of the sidewall rubber (rubber constituent part) G2, it is not necessary to temporarily stop the wound body D and align and affix the front end of the strip zone 11A, so that the formation efficiency can be improved. Further, the transition from the side wall rubber (rubber component) G2 to the clinch rubber (rubber component) G3 is smooth, which is useful for improving the shape accuracy of the entire wound body.

  Further, by using the longitudinal strip 12, the number of installed strip guide devices for guiding the strips from the rubber extrusion device to the wound body D can be reduced to the minimum, and the equipment structure for forming the raw tire can be simplified. Also, the equipment space and equipment cost can be reduced.

  Next, the longitudinal strip 12 can be continuously formed by a rubber extrusion device 15 shown below. As shown in FIG. 4, the rubber extruding device 15 includes a plurality of rubber extruder bodies 17 that extrude rubber compositions Gg having different rubber compositions from the extrusion ports 16 and one extrusion head 18.

  Each rubber extruder body 17 has a known structure in which a screw shaft 20 is housed in a cylinder 19 provided with a rubber inlet. Then, by driving the screw shaft 20, the rubber composition Gg to be charged can be extruded from the extrusion port 16 at the front end of the cylinder 19 while being plasticized.

  The extrusion head 18 includes a plurality of individual rubber channels 21 for guiding the rubber composition Gg from each of the extrusion ports 16 to the downstream side, a selection chamber 22 through which the plurality of individual rubber channels 21 communicate, and the selection It has a downstream flow path 23 extending from the chamber 22 and a discharge port 24 located at the downstream end of the downstream flow path 23.

  Specifically, the rubber extruding apparatus 15 of the present example includes a total of two first and second rubber extruder bodies 17A and 17B. Further, the extrusion head 18 includes a first individual rubber flow path 21A for guiding the rubber composition GgA from the first rubber extruder body 17A to the downstream side, and a second rubber extruder body 17B from the second rubber extruder body 17B. A second individual rubber channel 21B for guiding the rubber composition GgB to the downstream side is provided. The first and second individual rubber flow paths 21 </ b> A and 21 </ b> B communicate with one selection chamber 22, and one downstream flow path 23 extends from the selection chamber 22 to the discharge port 24.

  Here, the selection chamber 22 is provided with a switching valve 25 that selectively switches between and communicates with the downstream flow path 23 and the first and second individual rubber flow paths 21A and 21B. The switching valve 25 is a ball valve 25A in this example, and is housed in a spherical selection chamber 22 so as to be rotatable around the axis as shown in FIGS. 5 (A) and 5 (B). The The ball valve 25A is provided with, for example, a notch-shaped conducting portion 25A1, and the switching operation to the switching valve 25 (in this example, the rotation operation around the shaft core) and the downstream flow path 23 and the first flow path 25A1. It is possible to selectively switch between the individual rubber channel 21A and between the downstream channel 23 and the second individual rubber channel 21B. That is, the rubber composition GgA from the first rubber extruder main body 17A and the rubber composition GgB from the second rubber extruder main body 17B are sequentially selected and passed through the downstream flow path 23 from the discharge port 24. Can be discharged.

  At this time, at the time of the switching, the other rubber composition (for example, GgB) is connected to the rear end of one rubber composition (for example, GgA) that passes through the downstream flow path 23 in advance, and is switched. Accordingly, it is possible to continuously extrude the longitudinally joined strip 12 from the discharge port 24 in which the strip zones 11A and 11B made of the rubber compositions GgA and GgB are longitudinally joined in the length direction.

  Here, in the rubber extrusion device 15, the rubber composition GgA from one rubber extruder main body, for example, the first rubber extruder main body 17A is converted into the first individual rubber flow path 21A, the selection chamber 22, and the downstream flow path. 23, the second rubber extruder body 17B, which is the other rubber extruder body, is stopped while being pushed out from the discharge port 24 as the strip zone 11A, and the internal pressure of the second individual rubber channel 21B is excessively increased. Suppresses the rise. At this time, if the stop time of the other rubber extruder main body 17B is about 1 minute, the plasticity of the rubber composition GgB can be sufficiently maintained, and the other rubber extruder main body according to the switching of the switching valve 25. By operating 17B, the rubber composition GgB from the stopped rubber extruder body 17B can be pushed out from the discharge port 24 as the strip zone 11B through the selection chamber 22 and the downstream flow path 23.

  However, in order to reliably and stably push out the rubber composition Gg from the stopped rubber extruder main body from the discharge port 24, in this example, the rubber discharge amount control means 31 having the gear pump 30 in each individual rubber flow path 21. Is provided.

  As shown in FIG. 6, the gear pump 30 includes a pair of gears 30A meshing with each other, and a concave recess arc shape concentric with the gear 30A and accommodating each gear 30A, and the gear pump 30 that rotates. The upstream rubber composition Gg is pushed downstream by utilizing the space between the tooth groove of 30A and the wall surface of the housing recess 30B. The gear pump 30 is operated simultaneously with the switching of the switching valve 25, so that the stop time of the other rubber extruder body is as long as about 10 minutes, for example, and the plasticity of the rubber composition Gg on the stop side is reduced. Simultaneously with the switching, the rubber composition Gg can be stably supplied to the selection chamber 22 and the downstream flow path 23. The gear pump 30 can control and adjust the discharge amount for each rubber composition Gg. Therefore, even when the rubber composition Gg having different physical properties depending on the rubber composition is switched, the longitudinal strip 12 can be extruded with a constant cross-sectional shape without any difference in cross-sectional shape between the strip zones 11, and the rubber configuration The formation accuracy of the part G can be increased.

  FIG. 7 conceptually shows a case where the rubber extruding device 15 includes first to third total three rubber extruder main bodies 17A to 17C. In this example, the selection chamber 22 is divided into a first selection chamber portion 22a and a second selection chamber portion 22b, and the first and second rubber extruder bodies 17A and 17B extend from the first, The second individual rubber flow paths 21A and 21B communicate with the first selection chamber portion 22a. The joint flow path 32 extending from the first selection chamber section 22a and the third individual rubber flow path 21C extending from the third rubber extruder body 17C communicate with the second selection chamber section 22b. Further, the downstream flow path 23 extends to the discharge port 24 from the second selection chamber 22b.

  Switching valves 25a and 25b are arranged in the selection chamber portions 22a and 22b, respectively. Then, the rubber composition GgA, GgB from the first and second rubber extruder bodies 17A, 17B is selected by the switching operation of the switching valve 25a and sent out to the joint channel 32. Further, one of the selected rubber compositions GgA and GgB and the rubber composition GgC from the third rubber extruder main body 17C are selected by the switching operation of the switching valve 25b, and continuously to the downstream flow path 23. Can be sent out. That is, it is possible to extrude a longitudinal strip 12 (not shown) in which strip bands 11A to 11C made of rubber compositions GgA to GgC are freely cascaded.

  As the rubber composition GgC, by adopting a rubber having a composition for the inner liner rubber G4, for example, a side wall rubber (rubber component) G2 is formed by the strip zone 11A, and a clinch rubber (rubber component) G3 is formed by the strip zone 11B. After the formation, the inner liner rubber (rubber component) G4 can be continuously formed by the strip zone 11C made of the rubber composition GgC.

  FIG. 8 shows an example in which the base rubber part G1b and the cap rubber part G1a are sequentially formed using the longitudinal joining strip 12 composed of the strip bands 11A and 11B.

  As mentioned above, although especially preferable embodiment of this invention was explained in full detail, this invention is not limited to embodiment of illustration, It can deform | transform and implement in a various aspect.

It is sectional drawing which shows one Example of the pneumatic tire formed including the rubber | gum structural part manufactured by the manufacturing method of this invention. It is sectional drawing which shows the side wall rubber and clinch rubber which are formed using a longitudinal strip. It is a perspective view of a longitudinal connection strip. It is a diagram explaining a reference outline with a transverse groove. It is sectional drawing which shows the principal part of a rubber extrusion apparatus. (A), (B) is sectional drawing explaining the switching state by a switching valve. It is sectional drawing explaining a gear pump. It is sectional drawing which shows the other example of a switching valve. It is sectional drawing which shows an example of the base rubber | gum part and cap rubber | gum part of a tread formed using a longitudinal strip. (A) is sectional drawing explaining a part of green tire formation process by STW method, (B) is a perspective view of the facility explaining the problem of the conventional method.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Rubber strip 11, 11A-11C Strip zone 12 Longitudinal strip 15 Rubber extrusion device 16 Extrusion port 17, 17A-17C Rubber extruder main body 18 Extrusion head 21, 21A-21C Individual rubber flow path 22 Selection chamber 23 Downstream flow path 24 Discharge port 25 Switching valve 25A Ball valve 30 Gear pump 31 Rubber discharge amount control means G Rubber component Gg Rubber composition

Claims (4)

A tire rubber component manufacturing method for manufacturing a tire rubber component by winding an unvulcanized rubber strip in a spiral shape,
A rubber extrusion device continuously extrudes the rubber strip as a longitudinal strip in which a plurality of types of strip zones different in rubber composition are longitudinally connected,
According to each strip zone having a different rubber composition, the rubber component having a different tire is formed by winding the strip zone ,
The rubber extruding device comprises a plurality of rubber extruding machine bodies,
Between the rubber compositions from the plurality of rubber extruder bodies, by connecting the next rubber composition to the rear end of the preceding rubber composition using a switching valve,
A method for manufacturing a rubber component of a tire, wherein the longitudinal strip is extruded from a discharge port of the rubber extrusion device.   A rubber extrusion device for a longitudinal strip used in claim 1,
  A plurality of rubber extruder bodies for extruding rubber compositions having different rubber compositions from the extrusion ports,
  And a plurality of individual rubber passages for guiding the rubber composition from each of the extrusion ports to the downstream side, a selection chamber that communicates with the plurality of individual rubber passages, a downstream passage extending from the selection chamber, and a downstream end thereof And having an extrusion head having a discharge port located at
  The extrusion head includes a switching valve that selectively switches between the downstream flow path and the plurality of individual rubber flow paths in the selection chamber.
  By switching the switching valve, a plurality of rubber compositions from the extrusion port are sequentially selected and continuously sent out from the discharge port through the downstream flow path, thereby extending the strip zone made of each rubber composition. A rubber extruding device characterized in that it is extruded as a longitudinally connected strip.   The rubber extrusion device according to claim 2, wherein the switching valve is a ball valve.   4. The rubber extrusion apparatus according to claim 2, wherein the extrusion head includes a rubber discharge amount control means having a gear pump in each of the individual rubber flow paths.

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