Tread component with color line and method for manufacturing the tread component

Abstract

The present invention provides a tread component with a color line and a method for manufacturing the tread component, which can stably apply colored rubber to the tread component using a nozzle. The tread component (1) with a side color line (31) comprises: a tread component (1), which is a rubber extrusion profile extending along an extrusion direction E with a predetermined cross-sectional shape, and has a first main surface (2) constituting the outer peripheral surface (50a) in the tire radial direction of a raw tire (50) when wound into a cylindrical shape, and a pair of opposing wall surfaces (6a) extending along the extrusion direction (E) on the first main surface (2) and opposite to each other in a left-right direction orthogonal to the extrusion direction (E); and a colored rubber (30) extending along the extrusion direction (E) on the first main surface (2) and between the pair of opposing wall surfaces (6a).

Description

Technical Field

[0001] The present invention relates to a tread component having a color line and a method for manufacturing the tread component. Background Art

[0002] As is known, a tread component has a color line for identification and / or a color line as a reference line for assembly position on its outer surface. Patent document 1 discloses the following content: as a method for manufacturing a tread component with a color line, a rubber material is extruded from a die (die) in a predetermined cross-sectional shape, a tread component having a ridge extending along the extrusion direction is formed on the outer surface, and a color rubber adhesive is transferred to the top of the ridge using a wide transfer roller for coating.

[0003] Prior art literature

[0004] Patent Literature

[0005] Patent Document 1: Japanese Patent Application Laid-Open No. 2000-61999 Summary of the invention

[0006] The method of Patent Document 1 is that even when the rubber squeezed by the transfer roller is zigzag when the color line is applied, the color line can be stably applied to the ridge of the tread member by using a wide transfer roller. However, since the method of Patent Document 1 is a method of applying the color rubber by using a transfer roller, it is not applicable to the case where the color rubber is applied by using a nozzle.

[0007] An object of the present invention is to provide a tread member having a color line and capable of stably applying a colored rubber to the tread member using a nozzle, and a method for manufacturing the tread member.

[0008] The subject of one scheme of the present invention is to provide a tread component with a color line, comprising: a tread component, which is a rubber extrusion profile extending along a first direction with a predetermined cross-sectional shape, and has a first main surface constituting the outer peripheral surface of the tire radial direction of a green tire when wound into a cylindrical shape, and a pair of opposing wall surfaces extending along the first direction on the first main surface and opposite to each other in a second direction orthogonal to the first direction; and colored rubber extending along the first direction on the first main surface and between the pair of opposing wall surfaces.

[0009] According to the present invention, when applying colored rubber to a tread component that is extruded and extends along a first direction using a nozzle, by positioning the nozzle between a pair of opposing wall surfaces, even if the tread component is meandering in the width direction, the front end of the nozzle can be easily held between the pair of opposing wall surfaces by using the pair of opposing wall surfaces, thereby making it easy to apply the colored rubber between the pair of opposing wall surfaces. That is, since the colored rubber can be applied while suppressing the meandering of the colored rubber relative to the tread component, the meandering of the color line formed by the colored rubber in a pneumatic tire that is vulcanized and molded using the tread component is suppressed. Accordingly, the colored rubber can be stably applied to the tread component using the nozzle.

[0010] The length of the color rubber in the second direction, namely, the color rubber width, may be not less than 67% and not more than 133% of the length of the first main surface between the pair of opposing wall surfaces in the second direction, namely, the wall surface interval.

[0011] According to this configuration, it is easy to arrange the nozzle for applying the color rubber between a pair of opposing wall surfaces. When the width dimension of the color rubber exceeds 133% of the wall interval, it is difficult to arrange the nozzle between the pair of opposing wall surfaces. When the width dimension of the color rubber is less than 67% of the wall interval, since the nozzle can move along the width direction of the tread member between the pair of opposing wall surfaces, the meandering of the color rubber applied between the pair of opposing wall surfaces is likely to increase.

[0012] A height of the pair of opposing wall surfaces in a direction perpendicular to the first main surface may be greater than or equal to 3 mm and less than or equal to 4.5 mm.

[0013] According to this structure, it is easy to hold the nozzle for applying the colored rubber between the pair of opposing walls. When the height of the pair of opposing walls is less than 3 mm, the holding performance of the pair of opposing walls on the nozzle is deteriorated. When the height of the pair of opposing walls exceeds 4.5 mm, the portion constituting the pair of opposing walls is likely to flow in a manner covering the colored rubber during vulcanization molding, thereby deteriorating the recognition performance based on the colored rubber.

[0014] The tread member includes a pair of protrusions protruding from the first main surface and extending in the first direction, and the pair of opposing wall surfaces may be constituted by a pair of side surfaces of the pair of protrusions that are opposed to each other in the second direction.

[0015] According to this configuration, a pair of opposing walls can be easily formed by a pair of ridges. In addition, compared with the case where a pair of opposing walls are formed by grooves, it is easy to ensure the amount of rubber, thereby easily suppressing the rubber loss caused by the lack of rubber during vulcanization molding.

[0016] The tread member includes a groove that is recessed relative to the first main surface and extends along the first direction, and the pair of opposing wall surfaces may be constituted by two side surfaces that constitute the groove and that face each other in the second direction.

[0017] According to this configuration, the pair of opposing wall surfaces can be easily formed by the grooves. In addition, compared with the case where the pair of opposing wall surfaces are formed by a pair of protrusions, an increase in the amount of rubber can be suppressed.

[0018] The tread component comprises: a pair of protrusions protruding from the first main surface and extending along the first direction, and a groove recessed relative to the first main surface and extending along the first direction between the pair of protrusions, and the pair of opposing wall surfaces can be formed by a pair of side surfaces of the pair of protrusions that are opposite to each other in the second direction, and two side surfaces that constitute the groove and are opposite to each other in the second direction.

[0019] According to this configuration, a pair of opposing wall surfaces can be easily formed by a pair of ridges and grooves. In particular, the height of the ridges can be easily set low and the depth of the grooves can be easily set shallow, thereby easily achieving both ensuring the amount of rubber and suppressing the increase in the amount of rubber.

[0020] The wall surface interval may be greater than or equal to 1.5 mm and less than or equal to 6.0 mm.

[0021] According to this configuration, since the wall interval is 1.5 mm to 6.0 mm, for example, a nozzle for applying color rubber with a color rubber width of 2.0 mm to 4.0 mm can be easily arranged between a pair of opposing wall surfaces. Thus, a color line for component identification can be formed by using the color rubber applied between the pair of opposing wall surfaces.

[0022] The wall surface interval may be greater than or equal to 0.20 mm and less than or equal to 1.50 mm.

[0023] According to this configuration, since the wall surface interval is 0.20 mm or more and 1.50 mm or less, for example, a nozzle for applying the color rubber with a color rubber width of 0.25 mm or more and 1.00 mm or less can be easily arranged between a pair of opposing wall surfaces. Thus, a reference line serving as a reference for the assembly position when assembling a green tire can be formed by using the color rubber applied between the pair of opposing wall surfaces.

[0024] In the cross-sectional shape, the pair of opposing wall surfaces may be perpendicular to the first main surface or inclined in directions away from each other so as to form an angle of 60° or more and 90° or less with respect to the first main surface.

[0025] According to this configuration, the area where the colored rubber is applied and defined between the pair of opposing wall surfaces can be set to an appropriate size, so the amount of the colored rubber used can be optimized.

[0026] Another embodiment of the present invention provides a method for manufacturing a tread component with a color line, wherein rubber is extruded from a die along a first direction in a specified cross-sectional shape to form the tread component, wherein the tread component comprises: a first main surface which constitutes the outer peripheral surface in the radial direction of the raw tire when wound into a cylindrical shape, and a pair of opposing wall surfaces extending along the first direction on the first main surface and opposite to each other in a second direction orthogonal to the first direction, wherein the colored rubber is applied to the first main surface of the tread component conveyed along the first direction by a nozzle arranged between the pair of opposing wall surfaces.

[0027] According to the present invention, when manufacturing a tread member having a color line, the colored rubber can be stably applied using a nozzle while suppressing the colored rubber from meandering relative to the tread member. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Figure 1 It is a schematic diagram of a tread member manufacturing apparatus according to a first embodiment of the present invention.

[0029] Figure 2 is from Figure 1 The main view of the die observed in the direction of arrow A.

[0030] Figure 3 It is a three-dimensional diagram of the tread components.

[0031] Figure 4 This is a perspective view showing application of colored rubber to a tread member using a nozzle.

[0032] Figure 5 Yes Figure 4 A cross-sectional view showing a pair of side protrusions together with the nozzle at line V-V.

[0033] Figure 6 It is a pair of central ridges and Figure 5 Same cross-section.

[0034] Figure 7 The figure schematically shows the process of winding the tread member around the forming drum.

[0035] Figure 8 It is a perspective view schematically showing a green tire.

[0036] Fig. 9 2. A front view of a die according to a second embodiment

[0037] Fig.10It means to use Fig. 9 The tread components are extruded from the die. Figure 5 Same cross-section.

[0038] Fig.11 It is a front view of the die involved in the third embodiment.

[0039] Fig.12 It means to use Fig.11 The tread components are extruded from the die. Figure 5 Same cross-section.

[0040] Description of Reference Numerals

[0041] 1…tread component; 2…top surface of tread; 5…ridge; 6…side ridge; 6a…opposing wall; 7…center ridge; 7a…opposing wall; 16…nozzle; 17…nozzle; 20…die; 21…opening; 22…top surface of opening; 25…deficient portion; 26…side deficient portion; 27…center deficient portion; 30…colored rubber; 31…side color line; 32…center color line; 40…molding roller; 41…laser marker; 50…green tire; 51…tread ring; 53…carcass belt. DETAILED DESCRIPTION

[0042] Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings. Note that the following description is merely illustrative in nature, and the present invention is not intended to limit its applicable objects or uses.

[0043] [First embodiment]

[0044] Figure 1 The tread production line 10 for manufacturing the tread component 1 is schematically shown. Figure 1 As shown, the tread production line 10 includes: an extruder 11 for extruding a rubber material R into a predetermined cross-sectional shape to form a tread component 1, and a color rubber 30 (see Figure 3 ) is applied to the nozzles 16, 17 of the tread member 1.

[0045] The extruder 11 includes a hopper 12 for feeding a rubber material R, a screw 13 for kneading and conveying the rubber material R fed into the hopper 12, a drive source 14 (e.g., a motor) for driving the screw 13, and a die 20. The extruder 11 kneads and heats the rubber material R by rotating the screw 13 driven by the drive source 14, and extrude the rubber material R from the die 20 in an extrusion direction E (first direction). The extruded rubber material R constitutes a tread component 1 that is a long strip-shaped extruded profile having a predetermined cross-sectional shape.

[0046] The nozzles 16 and 17 are located at the downstream side in the extrusion direction E with respect to the extruder 11 , and apply the colored rubber 30 to the surface of the tread member 1 being conveyed.

[0047] Figure 2 is from Figure 1 A front view of the die 20 as viewed from the direction of arrow A in FIG. Figure 2 As shown, the die 20 has a horizontally long opening 21. The opening 21 has: an opening upper surface 22 and an opening bottom surface 23 extending along the left-right direction (second direction) orthogonal to the extrusion direction E, and a pair of opening side surfaces 24 extending along the up-down direction. The opening upper surface 22 is shorter than the opening bottom surface 23 in the left-right direction. The pair of opening side surfaces 24 connect the left and right side portions of the opening upper surface 22 with the left and right side portions of the opening bottom surface 23, respectively. The opening 21 is formed into a trapezoidal shape that is symmetrical with respect to the center line CL in the left-right direction. The rubber material R is extruded through the opening 21 of the die 20 in a trapezoidal cross-sectional shape.

[0048] A defective portion 25 is formed on the upper surface 22 of the opening, which is recessed upward and extends along the extrusion direction E. In the present embodiment, the die 20 has a pair of left and right side defective portions 26 and a pair of left and right center defective portions 27, which are formed on the left side of the upper surface 22 of the opening and in the center in the left-right direction, as the defective portions 25. In the present embodiment, the side defective portions 26 and the center defective portion 27 are formed, for example, by scoring the upper surface 22 of the opening along the extrusion direction E to form a triangular cross-section. In addition, the side defective portions 26 and the center defective portion 27 can be formed into any cross-sectional shape such as a rectangle, a trapezoid, a semicircle, and a curved surface.

[0049] The pair of side notches 26 are respectively recessed by an amount H1 of 3 mm or more and 4.5 mm or less from the opening upper surface 22, and the angle K1 formed with respect to the opening upper surface 22 is 90°, or they are respectively inclined at 60° or more in the direction away from each other. The distance D1 between the pair of side notches 26 in the left-right direction is 1.5 mm or more and 6.0 mm or less.

[0050] Similarly, the pair of center defective portions 27 are respectively recessed by an amount H2 of 3 mm or more and 4.5 mm or less from the opening upper surface 22, and the angle K2 formed with respect to the opening upper surface 22 is 90°, or they are respectively inclined at 60° or more in the direction away from each other. The distance D2 between the pair of center defective portions 27 in the left-right direction is 0.20 mm or more and 1.50 mm or less.

[0051] Figure 32 is a perspective view of a tread component 1. The tread component 1 has a cross-sectional shape corresponding to the shape of the opening 21 of the die 20, and has a first main surface 2 formed by an opening upper surface 22, a second main surface 3 formed by an opening bottom surface 23, and a pair of tread side surfaces 4 formed by a pair of opening side surfaces 24. Figure 3 In the embodiment of the present invention, the first main surface 2 and the second main surface 3 extend in the left-right direction. The first main surface 2 is shorter than the second main surface 3 in the left-right direction. A pair of tread side surfaces 4 connects the left and right side portions of the first main surface 2 and the left and right side portions of the second main surface 3 in the up-down direction. The tread component 1 is an elongated extruded profile extending in the extrusion direction E with a horizontally long cross-sectional shape.

[0052] The first main surface 2 is formed with a protrusion 5 extending in the extrusion direction E. The protrusion 5 includes a pair of side protrusions 6 formed by a pair of side notches 26 and a pair of center protrusions 7 formed by a pair of center notches 27 .

[0053] Figure 4 1 is a perspective view showing the periphery of the front end 16a of the nozzle 16. Figure 4 As shown, the front end 16a of the nozzle 16 is located between the pair of side ridges 6. The colored rubber 30 is supplied from the nozzle 16, and the colored rubber 30 is applied between the pair of side ridges 6 on the first main surface 2. Since the colored rubber 30 is applied to the first main surface 2 as the tread component 1 is conveyed in the extrusion direction E, the colored rubber 30 extends from the nozzle 16 to the downstream side of the extrusion direction E.

[0054] Figure 5 It is along Figure 4 It is a cross-sectional view of the tread component 1 along the V-V line, and is a cross-sectional view of the pair of side ridges 6 and the nozzle 16 located between the pair of side ridges 6 as viewed from the extrusion direction E. The pair of side ridges 6 are formed so that the cross-section corresponding to the shape of the pair of side notches 26 is triangular in shape. The protrusion amount X1 of the pair of side ridges 6 from the first main surface 2 is 3 mm or more and 4.5 mm or less, and the angle Y1 formed with respect to the first main surface 2 is 90°, or they are inclined at 60° or more in the direction away from each other. The inner diameter W1 of the nozzle 16 is 67% or more and 133% or less of the distance Z1 (wall interval) in the left-right direction on the first main surface 2 between the pair of side ridges 6. The inner diameter W1 of the nozzle 16 is 2.0 mm or more and 4.0 mm or less. Accordingly, the distance Z1 between the pair of opposing wall surfaces 6a on the first main surface 2 is 1.5 mm or more and 6.0 mm or less.

[0055] In this embodiment, the inner diameter W1 of the nozzle 16 is 3.0 mm, so the distance Z1 between the pair of side protrusions 6 is greater than 2 mm and less than 4 mm. In other words, in the die 20, the distance D1 between the pair of side notches 26 is set such that the distance Z1 between the pair of side protrusions 6 is within the above range. The pair of side protrusions 6 have: Figure 5 Opposing wall surfaces 6a that are opposed to each other in the left-right direction (in the horizontal direction).

[0056] The front end 16a of the nozzle 16 is located at a position higher than the first main surface 2 and lower than the apex of the pair of side ridges 6. That is, the front end 16a of the nozzle 16 is sandwiched between the pair of side ridges 6, that is, the pair of opposing wall surfaces 6a in the left-right direction. In the present embodiment, the distance Z1 between the pair of side ridges 6 is set to 2.0 mm, and by supplying the color rubber 30 from the nozzle 16, a side color line 31 extending along the extrusion direction E is formed between the pair of side ridges 6 on the first main surface 2 with a width F1 (color rubber width dimension) corresponding to the inner diameter W1 of the nozzle 16. In the present embodiment, the width F1 of the side color line 31 is substantially equal to the inner diameter W1 of the nozzle 16, and is greater than 2.0 mm and less than 4.0 mm.

[0057] Likewise, Figure 6 This is a cross-sectional view of the tread component 1 in which a pair of center ridges 7 and a nozzle 17 located between the pair of center ridges 7 are observed from the extrusion direction E. The pair of center ridges 7 are formed so that the cross-section corresponding to the shape of the pair of center missing portions 27 is triangular in shape. The protrusion amount X2 of the pair of center ridges 7 from the first main surface 2 is 3 mm or more and 4.5 mm or less, and the angle Y2 formed with respect to the first main surface 2 is 90°, or they are inclined at 60° or more in the direction away from each other. The inner diameter W2 of the nozzle 17 is 67% or more and 133% or less of the distance Z2 (wall interval) in the left-right direction on the first main surface 2 between the pair of center ridges 7. The inner diameter W2 of the nozzle 17 is 0.25 mm or more and 1.00 mm or less. Accordingly, the distance Z2 between the pair of opposing wall surfaces 7a on the first main surface 2 is 0.20 mm or more and 1.50 mm or less.

[0058] In this embodiment, since the inner diameter W2 of the nozzle 17 is 0.5 mm, the distance Z2 between the pair of center protrusions 7 is greater than or equal to 0.3 mm and less than or equal to 0.7 mm. In other words, in the die 20, the distance D2 between the pair of center defective portions 27 is set such that the distance Z2 between the pair of center protrusions 7 is within the above range. The pair of center protrusions 7 has: Figure 6 Opposing wall surfaces 7a that are opposed to each other in the left-right direction (in the horizontal direction).

[0059] The front end 17a of the nozzle 17 is located above the first main surface 2 and below the apex of the pair of center ridges 7. That is, the front end 17a of the nozzle 17 is sandwiched between the pair of center ridges 7, that is, the pair of opposing wall surfaces 7a in the left-right direction. In the present embodiment, the distance Z2 between the pair of center ridges 7 is set to 0.25 mm, and by supplying the color rubber 30 from the nozzle 17, a center color line 32 extending along the extrusion direction E is formed between the pair of center ridges 7 on the first main surface 2 with a width F2 (color rubber width dimension) corresponding to the inner diameter W2 of the nozzle 17. In the present embodiment, the width F2 of the center color line 32 is substantially equal to the inner diameter W2 of the nozzle 17, which is 0.25 mm or more and 1.00 mm or less.

[0060] Figure 7 The figure schematically shows a process of winding the tread component 1 coated with the side color line 31 and the center color line 32 on the first main surface 2 in a cylindrical shape on the forming drum 40 to form a tread ring 51. The forming drum 40 rotates around the central axis O1 to wind the tread component 1 around the outer periphery. The belt layer 52 is preliminarily wound around the forming drum 40. The tread component 1 is wound around the outer periphery of the belt layer 52.

[0061] At this time, the tread component 1 is wound along the circumferential direction of the forming drum 40 with the first main surface 2 positioned on the outer circumference. Thus, the tread component 1 is wound into a cylindrical shape with the side color line 31 and the center color line 32 extending along the outer circumference of the forming drum 40 on the outer circumferential surface.

[0062] In addition, the forming drum 40 is provided with a laser marker 41 that irradiates the center portion in the width direction with laser light. The tread component 1 is wound in such a manner that the center color line 32 and the laser light L irradiated from the laser marker 41 toward the forming drum 40 coincide with each other in the width direction of the forming drum 40. Thus, it is possible to suppress the tread component 1 from being displaced relative to the forming drum 40 in the width direction of the forming drum 40, and it is possible to easily and correctly wind the tread component 1. That is, the center color line 32 constitutes a reference line that serves as a reference for the assembly position when the tread component 1 is assembled to the forming drum 40.

[0063] Figure 8 : A three-dimensional view of a green tire 50 formed by bulging a separately formed carcass band 53 to the outer diameter side in an annular shape and attaching it to the inner circumferential surface of the tread ring 51. Figure 8 As shown, the outer peripheral surface 50 a of the raw tire 50 is constituted by the first main surface 2 of the tread member 1 , and the side color line 31 and the center color line 32 extend along the circumferential direction of the raw tire 50 .

[0064] The type of the green tire 50 can be identified by the color, width, and axial position of the side color line 31. Thus, the side color line 31 constitutes an identification color line for identifying the type of the tread member 1, the green tire 50, and the pneumatic tire (not shown) obtained by vulcanizing and molding the green tire 50.

[0065] According to the tread component 1 and the manufacturing method of the tread component 1 involved in the above-mentioned embodiment, the following effects can be produced. In addition, although the effects related to the pair of opposing wall surfaces 6a and the side color line 31 are described below, the same effects can be produced even with respect to the pair of opposing wall surfaces 7a and the center color line 32 unless otherwise emphasized, so the description thereof is omitted.

[0066] (1) The tread component 1 is a rubber extruded profile having a predetermined cross-sectional shape and extending along an extrusion direction E, and comprises: a tread component 1 having a first main surface 2 which constitutes an outer peripheral surface 50a in the radial direction of a raw tire 50 when wound into a cylindrical shape, and a pair of opposing wall surfaces 6a extending along the extrusion direction E and opposite to each other in a width direction orthogonal to the extrusion direction E on the first main surface 2; and a side color line 31 extending along the extrusion direction E on the first main surface 2 and between the pair of opposing wall surfaces 6a.

[0067] That is, in a method for manufacturing a tread component 1 having a side color line 31: a rubber material R is extruded from a die 20 along an extrusion direction E in a prescribed cross-sectional shape to form a tread component 1, wherein the tread component 1 comprises: a first main surface 2 which constitutes an outer peripheral surface 50a in the radial direction of a raw tire 50 when wound into a cylindrical shape, and a pair of opposing wall surfaces 6a extending along the extrusion direction E on the first main surface 2 and opposed to each other in a left-right direction orthogonal to the extrusion direction E, and a nozzle 16 is arranged between the pair of opposing wall surfaces 6a to apply the colored rubber 30 to the first main surface 2 of the tread component 1 conveyed along the extrusion direction E to form a side color line 31.

[0068] As a result, when the colored rubber 30 is applied to the tread component 1 extending along the extrusion direction E using the nozzle 16, by positioning the nozzle 16 between the pair of opposing wall surfaces 6a, even if the tread component 1 is meandering in the width direction, the front end 16a of the nozzle 16 can be easily held between the pair of side ridges 6 by the pair of opposing wall surfaces 6a, so that the colored rubber 30 can be easily applied between the pair of opposing wall surfaces 6a. That is, since the colored rubber 30 can be applied while being suppressed from meandering relative to the tread component 1, the meandering of the side color line 31 formed by the colored rubber 30 is suppressed in the pneumatic tire vulcanized and molded using the tread component 1. Accordingly, the colored rubber 30 can be stably applied to the tread component 1 using the nozzle 16.

[0069] In addition, if a plurality of rubber materials having different properties in the width direction of the tread component 1 are used as the rubber material R, the above-mentioned effect can be appropriately exerted, especially when the tread component 1 is prone to meandering in the width direction in the initial stage until the extrusion of the tread component 1 becomes stable.

[0070] (2) The width F1 of the side color line 31 is greater than 67% and less than 133% of the distance Z1 between a pair of opposing wall surfaces 6a. As a result, it is easy to arrange the nozzle 16 between the pair of opposing wall surfaces 6a. When the width F1 of the side color line 31 exceeds 133% of the distance Z1 between the pair of opposing wall surfaces 6a, it becomes difficult to arrange the nozzle 16 between the pair of opposing wall surfaces 6a. When the width F1 of the side color line 31 is less than 67% of the distance Z1 between the pair of opposing wall surfaces 6a, since the allowable amount of movement of the nozzle 16 along the width direction of the tread component 1 between the pair of opposing wall surfaces 6a becomes larger, it is easy to increase the meandering of the side color line 31 between the pair of opposing wall surfaces 6a.

[0071] (3) The height of the pair of side protrusions 6, i.e., the opposing wall surfaces 6a, in the direction perpendicular to the first main surface 2 is 3 mm or more and 4.5 mm or less. As a result, the nozzle 16 is easily held between the pair of opposing wall surfaces 6a. When the height of the pair of opposing wall surfaces 6a is less than 3 mm, the holding property of the pair of opposing wall surfaces 6a on the nozzle 16 is deteriorated. When the height of the pair of opposing wall surfaces 6a exceeds 4.5 mm, the pair of side protrusions 6 are likely to flow in a manner covering the side color lines 31 during vulcanization molding, so that the side color lines 31 are buried, thereby deteriorating the recognition based on the side color lines 31.

[0072] (4) The pair of opposing wall surfaces 6a are formed by a pair of side surfaces that are opposed to each other in the width direction of the pair of side protrusions 6. As a result, the pair of opposing wall surfaces 6a can be easily formed by the pair of side protrusions 6. In addition, compared with the case where the pair of opposing wall surfaces are formed by grooves, it is easy to ensure the amount of rubber, and rubber shortage caused by insufficient rubber amount during vulcanization molding can be suppressed.

[0073] (5) With respect to the pair of side protrusions 6, since the distance Z1 between the pair of opposing wall surfaces 6a is 1.5 mm or more and 6.0 mm or less, for example, the nozzle 16 for applying the color rubber 30 with a color rubber width dimension of 2.0 mm or more and 4.0 mm or less can be easily arranged between the pair of opposing wall surfaces 6a. Accordingly, the side color line 31 formed by the color rubber 30 applied between the pair of opposing wall surfaces 6a can be used to form a color line for component identification. In addition, when the width of the side color line 31 is less than 2.0 mm, the pair of side protrusions 6 easily flow in a manner covering the side color line 31 during vulcanization molding, so that the side color line 31 is buried, thereby deteriorating the recognition based on the side color line 31. When the width of the side color line 31 exceeds 4.0 mm, there is a possibility that the side color line 31 is transferred to the mold during vulcanization molding.

[0074] (6) With respect to the pair of center protrusions 7, since the distance Z2 between the pair of opposing wall surfaces 7a is 0.20 mm or more and 1.50 mm or less, the nozzle 17 for applying the color rubber 30 with a color rubber width dimension of 0.25 mm or more and 1.00 mm or less can be easily arranged between the pair of opposing wall surfaces 7a. Thus, the center color line 32 formed by the color rubber 30 applied between the pair of opposing wall surfaces 7a can be used to form a reference line as a reference for the assembly position when assembling the green tire. In addition, when the width F2 of the center color line 32 is less than 0.25 mm, it is difficult to stably apply the color rubber using the nozzle 17. When the width F2 of the center color line 32 exceeds 1.00 mm, the assembly accuracy is likely to deteriorate because the reference line as the assembly position is too thick.

[0075] (7) The angle Y1 formed by the opposing wall surfaces 6a of the pair of side protrusions 6 with respect to the first main surface 2 is set to be 60° or more and 90° or less so that the pair of opposing wall surfaces 6a are perpendicular to the first main surface 2 or inclined in a direction away from each other. As a result, the area where the colored rubber 30 is applied between the pair of opposing wall surfaces 6a can be set to an appropriate size, so that the amount of the colored rubber 30 used can be optimized. In addition, the larger the angle Y1 is, that is, the closer it is to 90°, the smaller the area where the colored rubber 30 is applied is, so the amount of the colored rubber 30 used can be reduced.

[0076] [Second embodiment]

[0077] Fig. 9 The second modification example involves the die 60 and Figure 2 The same main view, Fig.10 is the tread member 70 extruded from the die 60 and Figure 5 The same enlarged image. Fig. 9As shown, the die 60 is different from the die 20 in that the cutout portion 25 is replaced with a protrusion 65 protruding downward and extending along the extrusion direction E on the opening top surface 62 .

[0078] In this embodiment, the die 60 has a side protrusion 66 and a center protrusion 67 formed on the left side and the center in the left-right direction of the opening top surface 62, respectively, as the protrusion 65. The side protrusion 66 and the center protrusion 67 are formed into a trapezoidal shape whose distance in the left-right direction becomes shorter toward the bottom. In addition, the side protrusion 66 and the center protrusion 67 can also be configured into any cross-sectional shape such as a rectangle, a triangle, a semicircle, and a curved surface.

[0079] like Fig.10 As shown, in the tread member 70, a side groove 76 is formed by the side protrusion 66, which is recessed downward relative to the tread top surface 71. The side groove 76 is recessed into a trapezoid and has a pair of opposing wall surfaces 76a that are opposite to each other in the left-right direction. The front end 16a of the nozzle 16 is arranged between the pair of opposing wall surfaces 76a. Although not shown in the figure, a center groove is formed by the center protrusion 67, which is recessed downward relative to the tread top surface 71 into a trapezoid, and the front end 17a of the nozzle 17 is arranged between the pair of opposing wall surfaces that define the center groove.

[0080] According to the present embodiment, the pair of facing wall surfaces 76a can be easily formed by the side grooves 76. In addition, compared with the case where the pair of facing wall surfaces 6a are formed by the pair of side ridges 6 in the first embodiment, an increase in the amount of rubber can be suppressed.

[0081] [Third Embodiment]

[0082] Fig.11 The third modification example involves the die 80 and Figure 2 The same main view, Fig.12 The tread member 90 extruded from the die 80 is Figure 5 The same enlarged image. Fig.11 As shown, the die 80 is different from the die 20 in that a protrusion 85 protruding downward and extending along the extrusion direction E is provided on the opening top surface 82 .

[0083] In this embodiment, the die 80 has a side protrusion 86 formed between a pair of side notches 26 and a center protrusion 87 formed between a pair of center notches 27 as protrusions 85. The side protrusions 86 and the center protrusion 87 are formed in a trapezoidal shape that becomes shorter in the left-right direction toward the bottom so as to be continuous with the two mutually opposing side surfaces of the side notches 26 and the center notches 27. In addition, the side protrusions 86 and the center protrusion 87 may be configured in any cross-sectional shape such as a rectangle, a triangle, a semicircle, or a curved surface.

[0084] like Fig.12 As shown in the figure, the tread component 90 has a pair of side ridges 96 formed by a pair of side notches 26 so as to protrude upward from the tread top surface 91, and a side groove 97 formed by a side protrusion 86 so as to be recessed downward from the tread top surface. The mutually opposing side surfaces of the pair of side ridges 96 and the mutually opposing side surfaces of the side groove 97 are continuous in the up-down direction, and a pair of opposing wall surfaces 96a are formed by them. The front end 16a of the nozzle 16 is arranged between the pair of opposing wall surfaces 96a. Although not shown in the figure, even if a pair of center notches 27 and the center protrusion 87 are used, a pair of center ridges and a center groove can be formed in the same manner, and the front end 17a of the nozzle 17 is arranged between the mutually opposing opposing wall surfaces.

[0085] According to this embodiment, a pair of opposing wall surfaces 96a can be easily formed by a pair of side ridges 96 and side grooves 97. In particular, the height of the side ridges 96 can be easily set low and the depth of the side grooves 97 can be easily set shallow, thereby easily achieving both ensuring the amount of rubber and suppressing the increase in the amount of rubber.

[0086] In addition, the present invention is not limited to the configuration described in the above-mentioned embodiment, and various modifications can be made.

[0087] In the above embodiment, although the case where both the side color lines 31 and the center color line 32 are provided is described as an example, the present invention is not limited thereto. For example, the present invention can be applied to various cases such as a case where only the center color line 32 is provided, a case where only the side color lines 31 are provided, a case where a plurality of side color lines 31 are provided, and the like.

Claims

1. A tread component having a color line, characterized in that: have: A tread member, which is a rubber extruded profile extending in a first direction with a predetermined cross-sectional shape, and has a first main surface constituting an outer peripheral surface in a tire radial direction of a green tire when rolled into a cylindrical shape, and a pair of opposing wall surfaces extending in the first direction on the first main surface and opposing in a second direction orthogonal to the first direction; and a colored rubber on the first main surface and extending along the first direction between the pair of opposing wall surfaces, The tread member includes: a pair of ridges protruding from the first main surface and extending along the first direction, and a groove recessed with respect to the first main surface and extending along the first direction between the pair of ridges. The pair of opposing wall surfaces is formed by a pair of side surfaces of the pair of protrusions that are opposed to each other in the second direction and two side surfaces that constitute the groove and are opposed to each other in the second direction.

2. The tread component with a color line according to claim 1, characterized in that: The length of the color rubber in the second direction, namely, the color rubber width dimension, is not less than 67% and not more than 133% of the length in the second direction on the first main surface between the pair of opposing wall surfaces, namely, the wall surface interval.

3. The tread component with a color line according to claim 1 or 2, characterized in that: A height of the pair of opposing wall surfaces in a direction perpendicular to the first main surface is greater than or equal to 3 mm and less than or equal to 4.5 mm.

4. The tread component with a color line according to claim 2, characterized in that: The wall surface interval is greater than or equal to 1.5 mm and less than or equal to 6.0 mm.

5. The tread component with a color line according to claim 2, characterized in that: The wall surface interval is greater than or equal to 0.20 mm and less than or equal to 1.50 mm.

6. The tread component with a color line according to claim 1 or 2, characterized in that: In the cross-sectional shape, the pair of opposing wall surfaces form an angle of 60° or more and 90° or less with respect to the first main surface so as to be orthogonal to the first main surface or inclined in directions away from each other.

7. A method for manufacturing a tread component having a color line, characterized in that: The rubber is extruded from a die in a predetermined cross-sectional shape along a first direction to form a tread component, the tread component comprising: a first main surface constituting an outer peripheral surface of a raw tire in a tire radial direction when wound into a cylindrical shape, and a pair of opposing wall surfaces extending along the first direction on the first main surface and opposing each other in a second direction orthogonal to the first direction, wherein the tread component comprises: a pair of ridges protruding from the first main surface and extending along the first direction, and a groove recessed relative to the first main surface and extending along the first direction between the pair of ridges; the pair of opposing wall surfaces are constituted by a pair of side surfaces of the pair of ridges opposing each other in the second direction, and two side surfaces constituting the groove and opposing each other in the second direction, The colored rubber is applied to the first main surface of the tread member conveyed along the first direction by a nozzle disposed between the pair of opposing wall surfaces.

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