Tire manufacturing method and unvulcanized tread rubber part manufacturing device

Abstract

To make an unvulcanized tread rubber part into a targeted shape.SOLUTION: A manufacturing method of a tire includes: an extrusion molding process of extruding unvulcanized rubber to mold an extrusion molded product 20 of the unvulcanized rubber larger than an unvulcanized tread rubber part of a predetermined shape; and a cutting process of cutting off excess parts P1, P2 of the extrusion molded product 20 based on the predetermined shape of the unvulcanized tread rubber part.SELECTED DRAWING: Figure 9

Description

[Technical Field]

[0001] The present disclosure relates to a method for manufacturing a tire including manufacturing an unvulcanized tread rubber part, and an apparatus for manufacturing the unvulcanized tread rubber part. [Background technology]

[0002] A tire manufacturing method including a manufacturing step of an unvulcanized tread rubber part has been known for some time. For example, Patent Document 1 discloses a method in which unvulcanized rubber for forming a tread portion is extruded by an extruder, the extruded tread strip material is cut to a predetermined length to form an unvulcanized tread rubber part, and then both ends of the unvulcanized tread rubber part are joined into an annular shape.

[0003] According to Patent Document 1, the cut unvulcanized tread rubber parts are stored until they are moved to the next process, but the cut ends of the unvulcanized tread rubber parts tend to shrink in the longitudinal direction during storage. In Patent Document 1, a holding device with protrusions on the holding surface on which the unvulcanized tread rubber parts are placed is used to store the unvulcanized tread rubber parts. According to Patent Document 1, this is said to be highly effective in suppressing deformation of the unvulcanized tread rubber parts during storage. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Publication No. 2019-5989 Summary of the Invention [Problem to be solved by the invention]

[0005] Because unvulcanized rubber is a viscoelastic material, it is difficult to extrude it into a desired shape. Furthermore, as described in Patent Document 1, extrusion-molded products of unvulcanized rubber deform during storage. Therefore, even if the deformation of unvulcanized tread rubber parts during storage is suppressed using the method described in Patent Document 1, the shape of the unvulcanized tread rubber parts often does not achieve the desired shape. [Means for solving the problem]

[0006] The tire manufacturing method disclosed herein includes an extrusion molding step of extruding unvulcanized rubber to form an extruded product of unvulcanized rubber that is larger than an unvulcanized tread rubber part of a predetermined shape, and a cutting step of cutting off an excess portion of the extruded product based on the predetermined shape of the unvulcanized tread rubber part.

[0007] Also disclosed herein is an apparatus for manufacturing an unvulcanized tread rubber part, comprising an extrusion molding apparatus and a cutting apparatus. The extrusion molding apparatus comprises a die plate having holes formed therein through which unvulcanized rubber is extruded, and forms an extrusion-molded product of unvulcanized rubber having a cross-sectional shape corresponding to the holes. The cutting apparatus comprises a cutter that cuts the extrusion-molded product formed by the extrusion molding apparatus, and a control device that controls movement of the cutter. The die plate is configured to form the extrusion-molded product larger than a predetermined unvulcanized tread rubber part. The control device controls movement of the cutter based on the shape of the unvulcanized tread rubber part, causing it to cut off excess portions of the extrusion-molded product, thereby forming the unvulcanized tread rubber part.

[0008] According to the tire manufacturing method or the unvulcanized tread rubber part manufacturing apparatus, the unvulcanized tread rubber part can be formed into a desired shape. [Brief explanation of the drawings]

[0009] [Figure 1] 1 is a cross-sectional view of a tire according to one embodiment. [Figure 2] FIG. 2 is a cross-sectional view of an unvulcanized tread rubber part. [Figure 3] FIG. 2 is a plan view of an unvulcanized tread rubber part. [Figure 4] FIG. 2 is a process diagram showing a manufacturing process of an unvulcanized tread rubber part. [Figure 5] FIG. 1 is a schematic diagram showing the configuration of an unvulcanized tread rubber part manufacturing apparatus. [Figure 6] FIG. 4 is a front view showing the shape of a hole in a die plate. [Figure 7] FIG. 2 is a cross-sectional view of an extrusion molded product. [Figure 8] FIG. 2 is a plan view of an extrusion molded product. [Figure 9] FIG. 10 is a front view of the extrusion showing the cut line where the cutting device cuts the extrusion. [Figure 10] FIG. 1 is a schematic front view of the coring device and extrusion during a first cutting step. [Figure 11] FIG. 10 is a schematic front view of the cutting device and extrusion during the fourth cutting step. DETAILED DESCRIPTION OF THE INVENTION

[0010] The tire manufacturing method and manufacturing apparatus disclosed herein will be described below with reference to the drawings. Note that the present disclosure is not limited to the following embodiments. Each drawing is a schematic representation and does not necessarily reflect the actual product. Each drawing shows only an example and does not limit the present disclosure unless otherwise specified. Furthermore, members and parts that perform the same function are appropriately designated by the same reference numerals, and redundant explanations will be omitted.

[0011] FIG. 1 is a cross-sectional view of a tire 1 according to one embodiment. As shown in FIG. 1, the tire 1 includes a tread portion 2 that comes into contact with the ground when mounted on the wheel of an automobile or the like, a sidewall portion 3 that forms the side surface of the tire 1, shoulder portions 4 that connect the tread portion 2 and the sidewall portion 3, plies 5 that form the framework of the tire 1, and beads 6 that connect the tire to the wheel. The tire 1 is manufactured by vulcanizing a raw tire cover formed by wrapping the plies 5, beads 6, etc. with rubber components such as unvulcanized tread rubber parts and sidewall parts. The tread portion 2 is manufactured by winding a flat unvulcanized tread rubber part 10 (see FIG. 2) into a circular shape and joining both ends. Here, the process and apparatus for manufacturing the flat unvulcanized tread rubber part 10 will be described.

[0012] FIG. 2 is a cross-sectional view of the unvulcanized tread rubber part 10. FIG. 3 is a plan view of the unvulcanized tread rubber part 10. As shown in FIGS. 2 and 3, the unvulcanized tread rubber part 10 has a flat plate-like shape. As will be described in detail later, the unvulcanized tread rubber part 10 is formed by further adjusting the shape of an extrusion-molded product 20 (see FIG. 7) formed by extrusion molding of unvulcanized rubber. In the following, the extrusion direction of the unvulcanized rubber is defined as the forward direction and is represented by the symbol F. Up, down, left, and right refer to up, down, left, and right when viewed from the rear (symbol Rr). The up, down, left, and right directions are represented by arrows U, D, L, and R in the drawings, respectively. However, these directions are merely for the convenience of explanation and do not limit the installation orientation of the unvulcanized tread rubber part 10 or the tire manufacturing equipment. As shown in FIG. 3, the unvulcanized tread rubber part 10 has a flat plate shape extending in the extrusion direction in which the unvulcanized rubber is extruded and in the width direction (here, the left-right direction) perpendicular to the extrusion direction.

[0013] As shown in FIG. 2, the unvulcanized tread rubber part 10 includes a tread surface 11, a back surface 12 of the tread surface 11, and inclined surfaces 13 and thickness adjusting surfaces 14 that form side surfaces in the width direction. Here, the tread surface 11 forms the upper surface of the unvulcanized tread rubber part 10. The back surface 12 forms the lower surface of the unvulcanized tread rubber part 10. Note that both side surfaces in the extrusion direction are surfaces that are formed by cutting the unvulcanized tread rubber part 10 to a predetermined length. The inclined surfaces 13 are joined to unvulcanized sidewall parts.

[0014] The tread surface 11 extends in the extrusion direction (here, the front-rear direction) and the width direction (here, the left-right direction). Similarly, the back surface 12 of the tread surface 11 extends in the extrusion direction and the width direction. The length of the back surface 12 in the width direction is set to length L1. The inclined surface 13 is formed at an end of the unvulcanized tread rubber part 10 in the width direction, and is connected to the back surface 12 at a predetermined angle θ1. In the unvulcanized tread rubber part 10, the predetermined angle θ1 between the back surface 12 and the inclined surface 13 is set to an acute angle. As shown in FIG. 2, a boundary 15 between the back surface 12 and the inclined surface 13 is pointed when viewed in the extrusion direction.

[0015] In this embodiment, the inclined surface 13 is bent midway. The inclined surface 13 includes a first inclined surface 13A connected to the rear surface 12 and extending toward the center in the width direction, and a second inclined surface 13B connected to the first inclined surface 13A and further extending toward the center in the width direction. The inclination angle of the second inclined surface 13B relative to the rear surface 12 is greater than the inclination angle θ1 of the first inclined surface 13A relative to the rear surface 12. The inclined surface 13 is bent in this manner to facilitate contact with the unvulcanized sidewall part. The unvulcanized sidewall part has an end portion shaped to correspond to the inclined surface 13.

[0016] The unvulcanized tread rubber part 10 has a thickness adjusting surface 14 connected to the inclined surface 13 and the tread surface 11. The thickness adjusting surface 14 is set so that a height T1 of a boundary portion 14a with the inclined surface 13 relative to the back surface 12 is a predetermined height. This height T1 becomes the thickness of the unvulcanized tread rubber part 10 when joined to the sidewall part. By accurately forming the thickness of both the unvulcanized tread rubber part 10 and the thickness of the sidewall part, steps at the end of the tread portion 2 of the tire 1 are suppressed. The inclination angle θ2 of the thickness adjusting surface 14 relative to the back surface 12 is even smaller than the inclination angle θ1 of the first inclined surface 13A relative to the back surface 12. The thickness adjusting surface 14 is formed at an angle close to parallel to the tread surface 11 and the back surface 12.

[0017] A center line 11A is formed in the center in the width direction of the tread surface 11. The center line 11A is an example of a reference portion that serves as a reference for the position of the unvulcanized tread rubber part 10. As shown in Fig. 3, the center line 11A extends in the extrusion direction.

[0018] FIG. 4 is a process diagram showing the manufacturing process of the unvulcanized tread rubber part 10. As shown in FIG. 4, the manufacturing process of the unvulcanized tread rubber part 10 includes a mixing process S10, an extrusion molding process S20, a measuring process S30, a calculation process S40, and a cutting process S50. FIG. 5 is a schematic diagram showing the configuration of an unvulcanized tread rubber part manufacturing apparatus 100. As shown in FIG. 5, the unvulcanized tread rubber part manufacturing apparatus 100 includes an extrusion molding device 110, a measuring device 120, a calculation device 130, and a cutting device 140. The mixing process S10 is performed by the mixing device (not shown). The extrusion molding process S20 is performed by the extrusion molding device 110 shown in FIG. 5. The measuring process S30 is performed by the measuring device 120. The calculation process S40 is performed by the calculation device 130. The cutting process S50 is performed by the cutting device 140.

[0019] In the mixing step S10, various materials are mixed to produce unvulcanized rubber, which is the material for the unvulcanized tread rubber part 10. Although a detailed explanation will be omitted, multiple types of unvulcanized rubber with different viscosities (different hardness after vulcanization) may be produced in the mixing step S10. The multiple types of unvulcanized rubber with different viscosities are filled into different locations in the extrusion molding device 110 to form different portions of the unvulcanized tread rubber part 10.

[0020] In the extrusion molding step S20, unvulcanized rubber is extruded to form an extrusion-molded product 20 of unvulcanized rubber that is larger than the unvulcanized tread rubber part 10 having a predetermined shape. As shown in FIG. 5, the extrusion molding device 110 includes a die plate 111 having holes 112 through which the unvulcanized rubber is extruded. The extrusion molding device 110 forms the extrusion-molded product 20 of unvulcanized rubber having a cross-sectional shape corresponding to the holes 112. FIG. 6 is a front view showing the shape of the holes 112 of the die plate 111. As shown in FIG. 6, the holes 112 penetrate the die plate 111 in the extrusion direction. The holes 112 are formed in a shape that corresponds to the flat plate-shaped unvulcanized tread rubber part 10 to some extent. The holes 112 are flat through-holes that are long in the width direction. However, the holes 112 are configured to be larger than the cross-section of the unvulcanized tread rubber part 10.

[0021] In this example, the extrusion molding apparatus 110 includes, in addition to the die plate 111, an extrusion device (not shown) that extrudes unvulcanized rubber toward the holes 112 of the die plate 111, a cutting device that cuts the extrusion molded product 20 to a predetermined length, and a cooling device that cools the extrusion molded product 20. The configurations of the extrusion device, cutting device, and cooling device are not particularly limited. The extrusion molding apparatus 110 may also have configurations other than those described above.

[0022] Fig. 7 is a cross-sectional view of the extrusion-molded product 20. Fig. 8 is a plan view of the extrusion-molded product 20. As shown in Fig. 7, the extrusion-molded product 20 has a cross-sectional shape corresponding to the hole portions 112. However, due to shrinkage after extrusion, the cross section of the extrusion-molded product 20 is smaller than the hole portions 112. As shown in Fig. 7, the extrusion-molded product 20 includes a tread surface 21, a back surface 22, an intended inclined surface portion 23 that will become the inclined surface 13 when the extrusion-molded product 20 is made into the unvulcanized tread rubber part 10, an intended thickness adjusting surface portion 24 that will become the thickness adjusting surface 14 when the extrusion-molded product 20 is made into the unvulcanized tread rubber part 10, and an end portion 25. A center line 21A is molded in the tread surface 11.

[0023] As shown in Fig. 7, the extrusion-molded product 20 has surplus portions P1 and P2 that are cut off in the cutting step S50. In the extrusion molding step S20, the extrusion-molded product 20 is molded to have a first surplus portion P1 provided so as to cover the thickness adjusting surface 14 of the unvulcanized tread rubber part 10, and a second surplus portion P2 provided so as to cover the inclined surface 13. The first surplus portion P1 and the second surplus portion P2 are formed outside the thickness adjusting surface planned portion 24 and the inclined surface planned portion 23, respectively. The outline of the second surplus portion P2 when viewed in the extrusion direction is bent in the same manner as the inclined surface 13 of the unvulcanized tread rubber part 10.

[0024] In the extrusion molding step S20, the extrusion-molded product 20 is molded so that its widthwise length is longer than the widthwise length L1 of the unvulcanized tread rubber part 10. The end portion 25 is located outward in the widthwise direction from the boundary portion 15 between the back surface 12 and the inclined surface 13 of the unvulcanized tread rubber part 10. The end portion 25 is also cut off as part of the second surplus portion P2 in the cutting step S50. In this example, the end portion 25 is perpendicular to the back surface 22 (see also FIG. 9). However, the end portion 25 may be molded so as to form an obtuse angle with respect to the back surface 22. In the extrusion molding step S20, the second surplus portion P2 covering the inclined surface 13 is molded so as to form a right angle or an obtuse angle with respect to the back surface 22. As shown in FIG. 8, the width of the extrusion-molded product 20, particularly the central portion in the extrusion direction, is narrowed due to shrinkage after extrusion molding. Therefore, in a plan view, the end portion 25 is curved so as to be recessed inward in the widthwise direction.

[0025] Of the portions of the extrusion-molded product 20, the tread surface 21, the back surface 22, and the center line 21A are not cut off in the cutting step S50, and become the tread surface 11, the back surface 12, and the center line 11A of the unvulcanized tread rubber part 10 as they are.

[0026] As shown in FIG. 6, the hole portion 112 includes a tread surface molding portion 112A that molds the tread surface 21 of the extrusion-molded product 20, a back surface molding portion 112B that molds the back surface 22, a side surface molding portion 112C that forms the side surface, and a centerline molding portion 112D that forms the centerline 21A. The side surface molding portion 112C includes a first molding portion 112C1 that molds the outer surface of the first excess portion P1 and a second molding portion 112C2 that molds the outer surface of the second excess portion P2. As shown in FIG. 6, the second molding portion 112C2 rises vertically from the back surface molding portion 112B when viewed in the extrusion direction. The vertical portion of this second molding portion 112C2 molds the end portion 25. The second molding portion 112C2 extends obliquely upward from the upper end of the vertical portion toward the center of the hole portion 112 in the width direction. The oblique portion of the second molding portion 112C2 is bent so as to bend the outer contour of the second surplus portion P2. The first molding portion 112C1 connects the tread surface molding portion 112A and the second molding portion 112C2 so as to mold the outer surface of the first surplus portion P1.

[0027] In this way, the die plate 111 according to this embodiment is configured to mold an extrusion-molded product 20 that is larger than a predetermined unvulcanized tread rubber part 10. More specifically, the die plate 111 is configured to mold an extrusion-molded product 20 that is flat and extends in the extrusion direction and width direction, and whose width direction length is longer than the width direction length L1 of the unvulcanized tread rubber part 10. Furthermore, the die plate 111 is configured to mold an extrusion-molded product 20 that includes a tread surface 21, a back surface 22, a first excess portion P1 provided so as to cover the thickness adjusting surface 14, and a second excess portion P2 provided so as to cover the inclined surface 13.

[0028] In this embodiment, the die plate 111 is also configured to form the extrusion-molded product 20 in which the second surplus portion P2 covering the inclined surface 13 forms a right angle with the back surface 22. However, the die plate 111 may also be configured to form the extrusion-molded product 20 in which the second surplus portion P2 forms an obtuse angle with the back surface 22. The die plate 111 is also configured to form a center line 21A in the extrusion-molded product 20, which serves as a positional reference.

[0029] In the measurement step S30, the position of the centerline 21A is measured as a reference portion. The positions of the inclined surface 13 and the thickness adjustment surface 14 formed in the cutting step S50 are determined based on the position of the centerline 21A measured in the measurement step S30. The measurement device 120 is configured to measure the position of the centerline 21A. Here, the measurement device 120 measures the widthwise position and the up-down position of the centerline 21A. As shown in FIG. 5, the measurement device 120 includes a displacement sensor 121 that measures the distance to an object. The measurement device 120 acquires three-dimensional position data of the tread surface 21 by scanning the measurement point of the displacement sensor 121. The measurement device 120 recognizes the point near the center in the widthwise direction where peaks continue in the extrusion direction as the centerline 21A. Note that the centerline 21A does not have to be configured to protrude more than other portions. For example, the centerline may be recessed more than other portions.

[0030] However, this method of measuring the position of the center line 21A is merely an example. The method of measuring the position of the center line 21A is not particularly limited. The position of the center line 21A may be determined, for example, by analyzing an image captured by a camera. Furthermore, the reference point that serves as a reference for the position of the extrusion-molded product 20 is not limited to the center line 21A.

[0031] In the calculation step S40, the cutting position in the cutting step S50 is calculated based on the position of the center line 21A measured in the measurement step S30. The calculation device 130 calculates the movement of the cutter 142 by the control device 146 of the cutting device 140 based on the position of the center line 21A measured by the measuring device 120. The calculation device 130 is, for example, a computer connected to the measuring device 120 and the control device 146 of the cutting device 140. However, the calculation device 130 is not limited to a computer.

[0032] In the cutting step S50, the excess portions P1 and P2 of the extrusion-molded product 20 are cut off based on the predetermined shape of the unvulcanized tread rubber part 10. More specifically, the cutter 142 is moved in accordance with the movement of the cutter 142 calculated by the calculation device 130 based on the position of the center line 21A measured by the measurement device 120, and the excess portions P1 and P2 of the extrusion-molded product 20 are cut off. In this way, the unvulcanized tread rubber part 10 having the above-mentioned shape is formed.

[0033] 5, the cutting device 140 includes a tread receiving base 141, a cutter 142, a cutter driving unit 143, a cutter receiving member 144, a pressing member 145, and a moving device (not shown) that moves the cutter receiving member 144 and the pressing member 145. The cutting device 140 also includes a control device 146 that controls the operation of the cutting device 140.

[0034] The tread receiving base 141 is a base on which the extrusion-molded product 20 is placed. Here, the tread receiving base 141 is configured so that its widthwise length is narrower than that of the extrusion-molded product 20 (see FIG. 10 ). Therefore, both end portions in the widthwise direction of the extrusion-molded product 20, including the first surplus portion P1 and the second surplus portion P2, protrude outside the tread receiving base 141.

[0035] The cutter 142 cuts the extrusion-molded product 20 molded by the extrusion molding device 110. The cutter 142 is a flat-blade cutter. The cutter 142 has a blade extending in the front-rear direction at its lower end. Here, the cutter 142 is an ultrasonic cutter configured to vibrate the blade. However, the type of cutter 142 is not limited, and the cutter 142 may be, for example, a disk-shaped rotary cutter. The cutter driving unit 143 holds and moves the cutter 142. The cutter driving unit 143 according to this embodiment is configured to be able to move the cutter 142 in the up-down direction, left-right direction (width direction), and front-rear direction (extrusion direction). The cutter driving unit 143 is also configured to be able to change the elevation angle of the cutter 142 with respect to a horizontal plane. However, the cutter driving unit 143 may be configured not to move the cutter 142 in the front-rear direction (extrusion direction), for example. In that case, the tread receiving base 141 may move in the front-rear direction. Alternatively, the blade length of the cutter 142 may be longer than the length in the front-rear direction of the extrusion-molded product 20. Here, the cutting device 140 cuts off the first excess portion P1 and the second excess portion P2 of the extrusion-molded product 20 by moving the cutter 142 in the front-rear direction while moving it downward or diagonally downward using the cutter driving unit 143.

[0036] The cutter receiving member 144 is a member that supports the portion of the extrusion-molded product 20 that is to be cut by the cutter 142. The cutter receiving member 144 is disposed to the side of the tread receiving base 141 (see also FIG. 10 ). The cutter receiving member 144 supports the widthwise end of the extrusion-molded product 20 that extends outward beyond the tread receiving base 141 in the width direction. The cutter receiving member 144 may be formed with an escape groove so that the cutter 142 does not come into contact with the cutter 142 after cutting the extrusion-molded product 20. A moving device (not shown) may move the cutter receiving member 144 left and right to change the position of the escape groove according to the trajectory of the cutter 142.

[0037] The presser member 145 presses the first surplus portion P1 and the second surplus portion P2 that are cut off when the first surplus portion P1 and the second surplus portion P2 are cut off by the cutter 142 (see FIG. 10). The presser member 145 prevents the first surplus portion P1 or the second surplus portion P2 from being deformed by the pressure of the cutter, resulting in an inaccurate cutting line. A moving device (not shown) moves the position of the presser member 145 in accordance with the movement of the cutter 142.

[0038] The control device 146 controls the movement of the cutter 142. Here, the control device 146 controls the position and angle of the cutter 142 by controlling the cutter driving unit 143. The control device 146 controls the movement of the cutter 142 based on the shape of the unvulcanized tread rubber part 10, and causes the cutter 142 to cut away the excess portions P1 and P2 of the extrusion-molded product 20, thereby forming the unvulcanized tread rubber part 10. The control device 146 is, for example, a computer or a programmable controller. The configuration of the control device 146 is not particularly limited. The control device 146 may include, for example, a central processing unit (hereinafter referred to as CPU), a ROM in which programs to be executed by the CPU are stored, a RAM, and the like. The processing unit of the control device 146 may be configured by software or by hardware. The processing unit of the control device 146 may be a processor or a circuit.

[0039] 9 is a front view of the extrusion-molded product 20, showing cutting lines C1 to C4 along which the cutting device 140 cuts the extrusion-molded product 20. In this embodiment, the cutting device 140 cuts the extrusion-molded product 20 four times to form the unvulcanized tread rubber part 10. However, the paths of the cutting lines C1 to C4 and the cutting order shown in FIG. 9 are merely preferred examples.

[0040] In the cutting step S50, the control device 146 controls the movement of the cutter 142 to cut away the first excess portion P1 covering the thickness adjustment surface 14, thereby forming the thickness adjustment surface 14. Hereinafter, this step will also be referred to as a first cutting step S51 (see FIG. 4). Next, the control device 146 controls the movement of the cutter 142 to cut away the second excess portion P2 covering the inclined surface 13, thereby forming the inclined surface 13. The step of forming the inclined surface 13 includes a step of forming the first inclined surface 13A and a step of forming the second inclined surface 13B. In this embodiment, the formation of the second inclined surface 13B is performed before the formation of the first inclined surface 13A. Hereinafter, the step of forming the second inclined surface 13B will also be referred to as a second cutting step S52 (see FIG. 4). Furthermore, the step of forming the first inclined surface 13A will also be referred to as a third cutting step S53 (see FIG. 4).

[0041] Furthermore, the control device 146 controls the movement of the cutter 142 to cut off the end portion 25 of the extrusion-molded product 20 so that the widthwise length of the extrusion-molded product 20 coincides with the widthwise length L1 of the unvulcanized tread rubber part 10. Hereinafter, this step will also be referred to as a fourth cutting step S54 (see FIG. 4).

[0042] FIG. 10 is a schematic front view of the cutting device 140 and the extrusion-molded product 20 during the first cutting step S51. As shown in FIG. 10, in the first cutting step S51, the cutter 142 is tilted relative to the tread receiving base 141 by an angle θ2 between the back surface 12 of the unvulcanized tread rubber part 10 and the thickness adjusting surface 14 (see FIG. 2 for both). With the cutter 142 tilted as described above, it is moved obliquely downward so as to pass through a point 24a (see FIG. 9) that is a predetermined widthwise distance from the center line 21A and a height T1 from the top surface of the tread receiving base 141. At the same time, the cutter 142 is also moved in the extrusion direction. As a result, the first excess portion P1 is cut off, and the thickness adjusting surface 14 is formed. By forming the thickness adjusting surface 14, the thickness of the unvulcanized tread rubber part 10 becomes the predetermined thickness T1.

[0043] 10, in the first cutting step S51, the widthwise end of the extrusion-molded product 20 including the first surplus portion P1 is supported by a cutter receiving member 144. In addition, a pressing member 145 is in contact with the upper surface of the first surplus portion P1. The pressing member 145 presses the first surplus portion P1 to prevent the first surplus portion P1 from moving and shifting the first cutting line C1.

[0044] Although not shown, the second cutting step S52 and the third cutting step S53 are performed in the same manner as the first cutting step S51. The angle of the cutter 142 is changed between the second cutting step S52 and the third cutting step S53. The second cutting step S52 and the third cutting step S53 form an inclined surface 13 corresponding to the shape of the sidewall part, and the angle θ1 of the boundary portion 15 between the inclined surface 13 and the back surface 12 becomes an acute angle.

[0045] FIG. 11 is a schematic front view of the cutting device 140 and the extrusion-molded product 20 during the fourth cutting step S54. As shown in FIG. 11, during the fourth cutting step S54, the cutter 142 is supported vertically. The cutter 142 is positioned directly above the portion where the end of the unvulcanized tread rubber part 10 will be formed in the fourth cutting step S54 (at a position a distance L1 / 2 from the center line 21A in the width direction). From this state, the cutter 142 is moved straight downward. As a result, the length of the unvulcanized tread rubber part 10 in the width direction becomes the predetermined length L1.

[0046] 11 , in the fourth cutting step S54, the widthwise end of the extrusion-molded product 20 is supported by a cutter receiving member 144. In the fourth cutting step S54, only a small portion is cut off, and there is no need to press down on the extrusion-molded product 20, so the pressing member 145 is spaced apart from the extrusion-molded product 20.

[0047] Furthermore, as shown by the fourth cutting line C4 in FIG. 8, the first cutting step S51 to the fourth cutting step S54, at least the fourth cutting step S54, cuts off the end 25 of the extrusion-molded product 20 that is curved so as to be concave inward in the width direction, and the new end of the extrusion-molded product 20 becomes linear and extends in the extrusion direction.

[0048] As described above, according to the manufacturing method and manufacturing apparatus 100 for the tire 1 of this embodiment, by carrying out processes including an extrusion molding process S20 in which unvulcanized rubber is extruded to form an extrusion molded product 20 of unvulcanized rubber that is larger than an unvulcanized tread rubber part 10 of a predetermined shape, and a cutting process S50 in which excess portions P1 and P2 of the extrusion molded product 20 are cut off based on the predetermined shape of the unvulcanized tread rubber part 10, it is possible to form the unvulcanized tread rubber part 10 into a desired shape.

[0049] Conventionally, unvulcanized tread rubber parts 10 have been formed by extrusion molding of unvulcanized rubber. However, because unvulcanized rubber is a viscoelastic material, it has been difficult to achieve the desired shape through extrusion molding. Furthermore, the shape of an extrusion molded product made from unvulcanized rubber changes over time due to shrinkage. Therefore, the shape of the extrusion molded product had to be designed after predicting this change in shape. Furthermore, there are limitations to predicting the shape change of an extrusion molded product, making it even more difficult to achieve the desired shape of the extrusion molded product after shrinkage. Due to these constraints, conventionally, unvulcanized rubber extrusion molded products could not be sent to the next process unless they were stored until shrinkage had progressed to a certain extent and the shape change of the extrusion molded product had become less noticeable.

[0050] In contrast, according to the manufacturing method of the tire 1 according to the present embodiment, the extrusion-molded product 20 formed in the extrusion molding step S20 is larger than the unvulcanized tread rubber part 10, and the unvulcanized tread rubber part 10 is formed by cutting away excess portions P1 and P2 of the extrusion-molded product 20 in the cutting-out step S50. Because the cutting-out step S50 can be performed accurately, it is possible to manufacture the unvulcanized tread rubber part 10 in the desired shape. It is easy to mold the extrusion-molded product 20 larger than the unvulcanized tread rubber part 10 in the extrusion molding step S20.

[0051] According to this method, there is no need to store the extrusion-molded product 20 until the shrinkage converges. The unvulcanized tread rubber part 10, whose shape has been adjusted in the cutting step S50, stabilizes in shape when the unvulcanized tire is molded (pressed). Therefore, as long as the unvulcanized tread rubber part 10 is sent to the next step within a short time after the cutting step S50, the passage of time after the extrusion-molding step S20 is not particularly problematic. From the viewpoint of productivity, it is preferable to perform the measurement step S30, the calculation step S40, and the cutting step S50 following the extrusion-molding step S20, and then mold the unvulcanized tire following the cutting step S50.

[0052] Furthermore, in the extrusion molding step S20 of this embodiment, a reference portion (centerline 21A in this embodiment) that serves as a positional reference is formed in the extrusion-molded product 20. The manufacturing method of the tire 1 according to this embodiment further includes a measurement step S30 in which the position of the centerline 21A is measured, and a calculation step S40 in which a cut-off position in the cut-off step S50 is calculated based on the position of the centerline 21A measured in the measurement step S30. According to this method, the reference portion serves as a reference for the position of the extrusion-molded product 20, so the amounts of the excess portions P1 and P2 can be reduced. For example, if the extrusion-molded product does not have a reference portion, the position of the extrusion-molded product 20 in the cut-off step S50 cannot be accurately determined. Therefore, in order to reliably cut out the unvulcanized tread rubber part 10 without creating missing portions, it is necessary to set the excess portions P1 and P2 large. According to the method according to this embodiment, it is possible to reduce the waste of unvulcanized rubber that would otherwise be caused by forming such large excess portions P1 and P2.

[0053] In this embodiment, the unvulcanized tread rubber part 10 has a flat plate shape extending in the extrusion direction in which the unvulcanized rubber is extruded and in a width direction perpendicular to the extrusion direction. In the extrusion molding step S20, the extrusion-molded product 20 is molded to have a flat plate shape extending in the extrusion direction and the width direction, and to have a width length longer than the width length L1 of the unvulcanized tread rubber part 10. In the cutting step S50 (more specifically, the fourth cutting step S54), an excess portion of the extrusion-molded product 20 is cut off so that the width length of the extrusion-molded product 20 matches the width length L1 of the unvulcanized tread rubber part 10. This method makes it possible to accurately determine the width length of the unvulcanized tread rubber part 10.

[0054] As will be described later in the description of the examples, by accurately measuring the widthwise length of the unvulcanized tread rubber part 10, it is possible to suppress, for example, bare shoulders (a defect in which an unfilled portion occurs in the shoulder portion 4 of the tire 1 after vulcanization). In this case, the bare shoulders are caused by a mismatch between the air vent portion of the vulcanization mold and a predetermined portion of the unvulcanized tread rubber part 10 due to an inaccurate widthwise length of the unvulcanized tread rubber part 10. Note that, as will be described in more detail in the examples, the above-described effect of suppressing bare shoulders can be obtained simply by performing a step corresponding to the fourth cutting step S54 of this embodiment.

[0055] In this embodiment, the unvulcanized tread rubber part 10 has a flat plate-like shape including a tread surface 11 extending in the extrusion direction and the width direction, a back surface 12 of the tread surface 11, and an inclined surface 13 formed at an end in the width direction and connected to the back surface 12 at a predetermined angle θ1. In the extrusion molding step S20, the extrusion-molded product 20 is molded to include the tread surface 11, the back surface 12, and a second excess portion P2 provided to cover the inclined surface 13. In the cutting step S50, the second excess portion P2 covering the inclined surface 13 is cut away to form the inclined surface 13. This method allows the inclined surface 13 to be accurately formed by cutting. By accurately forming the inclined surface 13, it is possible to prevent a problem of a step being formed at the end of the tread portion 2 in the tire 1 after vulcanization.

[0056] More specifically, in this embodiment, the predetermined angle θ1 between the back surface 12 and the inclined surface 13 of the unvulcanized tread rubber part 10 is set to an acute angle. Meanwhile, in the extrusion molding step S20, the second excess portion P2 covering the inclined surface 13 is molded so as to form a right angle with the back surface 12. By setting the angle θ1 between the back surface 12 and the inclined surface 13 of the unvulcanized tread rubber part 10 to an acute angle, it is possible to effectively prevent a problem in which a step is formed at the end of the tread portion 2 in the tire 1 after vulcanization.

[0057] In unvulcanized tread rubber parts manufactured by conventional extrusion molding, the boundary between the back surface and the inclined surface is molded to form a right angle or an obtuse angle, and the inclined portion is connected to the right angle or obtuse angle portion. In other words, in unvulcanized tread rubber parts manufactured by conventional extrusion molding, the boundary between the back surface and the inclined surface is flattened and not sharp. This is because it is difficult to mold sharp edges when extruding unvulcanized rubber. When trying to mold sharp edges when extruding unvulcanized rubber, molding defects such as roughness are likely to occur.

[0058] In contrast, in the method according to this embodiment, the second surplus portion P2 of the extrusion-molded product 20 is molded so as to form a right angle with the back surface 12. This prevents molding defects in the extrusion molding step S20. Then, in the subsequent cutting step S50, the acute-angled boundary portion 15 is cut out. In this embodiment, this prevents molding defects while also preventing steps at the end of the tread portion 2. Note that the second surplus portion P2 may be molded so as to form an obtuse angle with the back surface 12.

[0059] In this embodiment, the unvulcanized tread rubber part 10 has a thickness adjusting surface 14 connected to the inclined surface 13 and the tread surface 11. As shown in FIG. 2 , the thickness adjusting surface 14 is set so that the height of a boundary portion 14a between the thickness adjusting surface 14 and the inclined surface 13 relative to the back surface 12 is a predetermined height T1. In the extrusion molding step S20, the extrusion-molded product 20 is molded so as to have a first excess portion P1 provided so as to cover the thickness adjusting surface 14. In the cutting step S50, the thickness adjusting surface 14 is formed by cutting away the first excess portion P1 covering the thickness adjusting surface 14. According to this method, the thickness of the unvulcanized tread rubber part 10 can be accurately adjusted by cutting.

[0060] As will be described later in the description of examples, by accurately determining the thickness of the unvulcanized tread rubber part 10, it is possible to suppress, for example, conicity (a problem in which lateral force is generated due to the tire 1 becoming a truncated cone after vulcanization). The effect of suppressing conicity by the method of this embodiment will be described in the examples.

[0061] Examples and comparative examples will be described below. Table 1 below shows the implementation conditions and evaluation results of the examples and comparative examples. For each of the examples and comparative examples, 100 tires were manufactured under the conditions shown in Table 1, and the dimensions, appearance, and productivity were evaluated. [Table 1]

[0062] In Table 1, "none" in the "cutting method" column indicates that no cutting process is performed after the extrusion molding process. "No cutting" refers to the conventional method, and Comparative Examples 1 to 3 are manufactured under the "no cutting" condition. "Width cutting" in the "cutting method" column indicates that only the excess portion in the width direction is cut off after the extrusion molding process (corresponding to performing only the fourth cutting step S54 in the embodiment). "Width, side, and thickness cutting" in the "cutting method" column indicates that all cutting steps corresponding to the first cutting step S51 to the fourth cutting step S54 in the embodiment are performed after the extrusion molding process. As shown in Table 1, width cutting is performed in Example 1. Width, side, and thickness cutting are performed in Example 2.

[0063] As shown in Table 1, the comparative examples vary in storage time from extrusion molding to the next process (the tire molding process in the comparative examples). In comparative example 1, the storage time from extrusion molding to the tire molding process is 0 hours. In comparative example 2, the storage time from extrusion molding to the tire molding process is 2 hours. In comparative example 3, the storage time from extrusion molding to the tire molding process is 5 hours. In the examples, the storage time from extrusion molding to the next process (the measurement process in the examples) is 0 hours. Tire productivity is higher when this storage time is shorter.

[0064] Among the evaluation items, the "dimensions immediately before molding" measures the deviation (unit: mm) of the width and thickness of the unvulcanized tread rubber parts from the design values. Table 1 shows the average and standard deviation of the deviation from the design values ​​of width and thickness.

[0065] Among the evaluation items, "Tire Appearance / FV Performance" evaluates bare shoulders and conicity of tires after vulcanization. The occurrence rate of bare shoulders is calculated. Whether bare shoulders have occurred or not is determined by visual inspection. Conicity is evaluated by measuring the lateral force (unit: N) generated when the tire is positioned on a truncated cone. Table 1 shows the average value and standard deviation of conicity.

[0066] As shown in Table 1, in Comparative Examples 1 to 3, the deviation (average value) of the width and thickness of the unvulcanized tread rubber part from the design value decreases as the storage time increases. The standard deviation of the deviation also decreases, and the variation also decreases. However, as the storage time increases, productivity decreases.

[0067] In Examples 1 and 2, the deviation (average value) of the width of the unvulcanized tread rubber part from the design value is significantly smaller than in Comparative Examples 1 to 3. The standard deviation is also significantly reduced, and the variation is also reduced. This shows that cutting the extrusion-molded product in the width direction improves the dimensional accuracy of the width of the unvulcanized tread rubber part immediately before molding. Since the storage time in Examples 1 and 2 is 0 hours, it is also clear that no storage time is necessary.

[0068] In Example 2, the deviation (average value) of the thickness of the unvulcanized tread rubber part from the design value is significantly smaller than in Comparative Examples 1 to 3 and Example 1. The standard deviation is also significantly reduced, and the variation is also reduced. This shows that cutting the extrusion-molded product in the thickness direction improves the dimensional accuracy of the thickness of the unvulcanized tread rubber part immediately before molding. Since the storage time in Example 2 is 0 hours, it is also clear that no storage time is necessary. In Example 1, the excess portion in the thickness direction is not cut off, so the deviation (average value and standard deviation) of the thickness of the unvulcanized tread rubber part from the design value is the same as in Comparative Example 1.

[0069] As shown in Table 1, in Comparative Examples 1 to 3, the incidence of bare shoulders decreased as the storage time increased. However, productivity decreased as the storage time increased. In Examples 1 and 2, the incidence of bare shoulders was smaller than in Comparative Examples 1 to 3. There was no difference in the incidence of bare shoulders between Examples 1 and 2. This shows that cutting the extrusion-molded product in the width direction suppresses the occurrence of bare shoulders.

[0070] As shown in Table 1, in Comparative Examples 1 to 3, the longer the storage time, the smaller the conicity (average value). The standard deviation of the conicity also decreased, and the variation became smaller. In Example 2, the conicity (average value) was smaller than in Comparative Examples 1 to 3. The standard deviation was significantly reduced, and the variation became smaller. This shows that cutting the extrusion-molded product in the thickness direction improves the conicity. In Example 1, the excess portion in the thickness direction was not cut off, and so the conicity was equivalent to that of Comparative Example 1.

[0071] From the above results, it can be seen that the occurrence of bare shoulders is suppressed when cutting in the width direction (fourth cutting step) in the method according to this embodiment. This effect is independent of the storage time after extrusion molding. Furthermore, the occurrence of conicity is suppressed when cutting in the thickness direction (first cutting step) in the method according to this embodiment. This effect is also independent of the storage time after extrusion molding. The cutting process of cutting off the excess portion of the extrusion molded product significantly improves the dimensional accuracy of the unvulcanized tread rubber part. Even if the storage time of the extrusion molded product after the extrusion molding process is not ensured, there is no problem with the quality of the tire after vulcanization.

[0072] Various descriptions have been given above regarding the tire manufacturing method and the unvulcanized tread rubber part manufacturing apparatus disclosed herein. However, the tire manufacturing method and manufacturing apparatus disclosed herein are not limited to the above-described embodiments unless otherwise specified. For example, the tire manufacturing method may not include a measurement step and a calculation step. In such a method, for example, the unvulcanized tread rubber part is formed from an extrusion molded product without providing a reference position on the extrusion molded product. In such a case, the unvulcanized tread rubber part manufacturing apparatus may not include a measurement device and a calculation device.

[0073] The shape of the unvulcanized tread rubber part described above is merely an example and is not particularly limited. In addition, the portions to be cut in the extrusion molded product and the portions to be left as they are in the extrusion molded product may be set appropriately, and the entire outer shape of the unvulcanized tread rubber part may be formed by the cutting process.

[0074] The manufacturing apparatus for unvulcanized tread rubber parts is not limited to the above. For example, the cutter may be a non-contact cutter capable of cutting an extrusion molded product of unvulcanized rubber. The configuration of the manufacturing apparatus, such as the tread receiving base, cutter receiving member, and pressing member, may be appropriately changed, added, or omitted. Furthermore, the configurations of the various embodiments and modified examples mentioned above may be appropriately combined as long as they do not interfere with each other. This specification includes the following disclosure, and the following disclosure is not limited to the above-mentioned embodiments.

[0075] The present disclosure (1) is a method for manufacturing a tire, including an extrusion molding step of extruding unvulcanized rubber to form an extruded product of unvulcanized rubber that is larger than an unvulcanized tread rubber part of a predetermined shape, and a cutting step of cutting off an excess portion of the extruded product based on the predetermined shape of the unvulcanized tread rubber part.

[0076] The present disclosure (2) is a method for manufacturing a tire according to the present disclosure (1), wherein a reference portion serving as a positional reference is formed in the extrusion molding step. The tire manufacturing method according to the present disclosure (2) further includes a measurement step of measuring the position of the reference portion, and a calculation step of calculating a cutting position in the cutting step based on the position of the reference portion measured in the measurement step.

[0077] The present disclosure (3) is a method for manufacturing a tire according to the present disclosure (1) or (2), wherein the unvulcanized tread rubber part has a flat plate shape extending in an extrusion direction in which the unvulcanized rubber is extruded and in a width direction perpendicular to the extrusion direction. In the extrusion molding step, the extrusion-molded product has a flat plate shape extending in the extrusion direction and the width direction, and is molded so that its width direction length is longer than that of the unvulcanized tread rubber part. In the cutting step, an excess portion of the extrusion-molded product is cut off so that the width direction length of the extrusion-molded product matches the width direction length of the unvulcanized tread rubber part.

[0078] The present disclosure (4) is a method for manufacturing a tire according to any one of the present disclosures (1) to (3), wherein the unvulcanized tread rubber part has a flat plate shape including a tread surface extending in an extrusion direction in which the unvulcanized rubber is extruded and in a width direction perpendicular to the extrusion direction, a back surface of the tread surface, and an inclined surface formed at an end of the width direction and connected to the back surface at a predetermined angle. In the extrusion molding process, the extrusion molded product is molded to include the tread surface, the back surface, and an excess portion provided to cover the inclined surface. In the cutting process, the excess portion covering the inclined surface is cut away to form the inclined surface.

[0079] The present disclosure (5) is a method for manufacturing a tire according to the present disclosure (4), wherein the predetermined angle between the back surface and the inclined surface of the unvulcanized tread rubber part is set to an acute angle. In the extrusion molding process, an excess portion covering the inclined surface is molded to form a right angle or an obtuse angle with the back surface.

[0080] The present disclosure (6) is a method for manufacturing a tire according to the present disclosure (4) or (5), wherein the unvulcanized tread rubber part includes a thickness adjusting surface connected to the inclined surface and the tread surface. The thickness adjusting surface is set so that the height of the boundary portion with the inclined surface relative to the back surface is a predetermined height. In the extrusion molding process, the extrusion molded product is molded to include an excess portion provided to cover the thickness adjusting surface. In the cutting process, the excess portion covering the thickness adjusting surface is cut away to form the thickness adjusting surface.

[0081] The present disclosure (7) relates to an apparatus for manufacturing an unvulcanized tread rubber part, the apparatus comprising an extrusion molding apparatus and a cutting device. The extrusion molding apparatus comprises a die plate having holes formed therein through which unvulcanized rubber is extruded, and forms an extrusion-molded product of unvulcanized rubber having a cross-sectional shape corresponding to the holes. The cutting device comprises a cutter that cuts the extrusion-molded product formed by the extrusion molding apparatus, and a control device that controls movement of the cutter. The die plate is configured to form the extrusion-molded product that is larger than a predetermined unvulcanized tread rubber part. The control device controls movement of the cutter based on the shape of the unvulcanized tread rubber part, causing it to cut off excess portions of the extrusion-molded product, thereby forming the unvulcanized tread rubber part.

[0082] The present disclosure (8) is the manufacturing device for unvulcanized tread rubber parts according to the present disclosure (7), wherein the die plate is configured to mold a reference portion serving as a positional reference in the extrusion-molded product. The manufacturing device for unvulcanized tread rubber parts according to the present disclosure (8) further includes a measuring device that measures the position of the reference portion, and a computing device that calculates the movement of the cutter by the control device based on the position of the reference portion measured by the measuring device.

[0083] The present disclosure (9) is the manufacturing device for an unvulcanized tread rubber part according to the present disclosure (7) or (8), wherein the unvulcanized tread rubber part has a flat plate-like shape extending in an extrusion direction in which the unvulcanized rubber is extruded and in a width direction perpendicular to the extrusion direction. The die plate is configured to mold the extrusion-molded product, which has a flat plate-like shape extending in the extrusion direction and the width direction and has a width length longer than that of the unvulcanized tread rubber part. The control device controls the movement of the cutter to cut off an excess portion of the extrusion-molded product so that the width length of the extrusion-molded product matches the width length of the unvulcanized tread rubber part.

[0084] The present disclosure (10) is a manufacturing device for an unvulcanized tread rubber part according to any one of the present disclosures (7) to (9), wherein the unvulcanized tread rubber part has a flat plate-like shape including a tread surface extending in an extrusion direction in which the unvulcanized rubber is extruded and in a width direction perpendicular to the extrusion direction, a back surface of the tread surface, and an inclined surface formed at an end of the width direction and connected to the back surface at a predetermined angle. The die plate is configured to mold the extrusion-molded product including the tread surface, the back surface, and an excess portion provided to cover the inclined surface. The control device forms the inclined surface by controlling the movement of the cutter to cut off the excess portion covering the inclined surface.

[0085] The present disclosure (11) is a manufacturing device for an unvulcanized tread rubber part according to the present disclosure (10), wherein the predetermined angle between the back surface and the inclined surface in the unvulcanized tread rubber part is set to an acute angle, and the die plate is configured to mold the extrusion molded product such that an excess portion covering the inclined surface forms a right angle or an obtuse angle with the back surface.

[0086] The present disclosure (12) is a manufacturing device for an unvulcanized tread rubber part according to the present disclosure (10) or (11), wherein the unvulcanized tread rubber part includes a thickness adjustment surface connected to the inclined surface and the tread surface. The thickness adjustment surface is set so that the height of the boundary between the thickness adjustment surface and the inclined surface relative to the back surface is a predetermined height. The die plate is configured to mold the extrusion-molded product with an excess portion provided to cover the thickness adjustment surface. The control device forms the thickness adjustment surface by controlling the movement of the cutter to cut off the excess portion covering the thickness adjustment surface. [Explanation of symbols]

[0087] 10 Unvulcanized tread rubber parts 11 Tread surface 11A Center line (reference point) 12 Back side 13 Slope 14 Thickness adjustment surface 20 Extrusion moldings 100 Unvulcanized tread rubber parts manufacturing equipment 110 Extrusion molding equipment 111 Die Plate 112 Hole 120 Measuring Equipment 130 Arithmetic equipment 140 Cutting device 142 Cutter 146 Control Device P1 First surplus part (surplus part) P2 Second surplus part (surplus part) S20 Extrusion molding process S30 measurement process S40 Calculation process S50 Cutting process

Claims

1. an extrusion molding step of extruding unvulcanized rubber to form an extrusion molded product of unvulcanized rubber larger than the unvulcanized tread rubber part having a predetermined shape; a cutting step of cutting off an excess portion of the extrusion molded product based on the predetermined shape of the unvulcanized tread rubber part, In the cutting step, the excess portion is cut off using a cutting device including a cutter that cuts the extrusion molded product and a control device that controls the movement of the cutter; In the extrusion molding step, a reference portion serving as a positional reference is formed in the extrusion molded product, a measuring step of measuring the position of the reference portion by a measuring device; and a calculation step of calculating a movement of the cutter by the control device in the cutting step based on the position of the reference portion measured by the measuring device in the measuring step. Tire manufacturing method.

2. An extrusion molding process for extruding unvulcanized rubber to form an extrusion molded product of unvulcanized rubber larger than an unvulcanized tread rubber part having a predetermined shape; a cutting step of cutting off an excess portion of the extrusion molded product based on the predetermined shape of the unvulcanized tread rubber part, The unvulcanized tread rubber part is a tread surface extending in an extrusion direction in which the unvulcanized rubber is extruded and in a width direction perpendicular to the extrusion direction; A back surface of the tread surface; a flat plate-like shape including an inclined surface formed at an end in the width direction and connected to the back surface at a predetermined angle; In the extrusion molding step, the extrusion molded product is molded to have the tread surface, the back surface, and an excess portion provided to cover the inclined surface, In the cutting step, the inclined surface is formed by cutting away an excess portion covering the inclined surface. Tire manufacturing method.

3. In the unvulcanized tread rubber part, the predetermined angle between the back surface and the inclined surface is set to an acute angle, In the extrusion molding step, the excess portion covering the inclined surface is molded so as to form a right angle or an obtuse angle with the back surface. A method for manufacturing a tire according to claim 2.

4. the unvulcanized tread rubber part includes a thickness adjusting surface connected to the inclined surface and the tread surface, the thickness adjusting surface is set so that a height of a boundary portion between the thickness adjusting surface and the inclined surface with respect to the rear surface is a predetermined height, In the extrusion molding step, the extrusion molded product is molded to have an excess portion provided so as to cover the thickness adjustment surface, In the cutting step, an excess portion covering the thickness adjusting surface is cut away to form the thickness adjusting surface. The method for manufacturing a tire according to claim 2 or 3.

5. In the extrusion molding step, a reference portion serving as a positional reference is formed in the extrusion molded product, a measuring step of measuring the position of the reference portion; a calculation step of calculating a cutting position in the cutting step based on the position of the reference portion measured in the measuring step, The method for manufacturing a tire according to any one of claims 2 to 4.

6. the unvulcanized tread rubber part has a flat plate shape extending in an extrusion direction in which the unvulcanized rubber is extruded and in a width direction perpendicular to the extrusion direction, In the extrusion molding step, the extrusion-molded product has a flat plate shape extending in the extrusion direction and the width direction, and is molded so that the length in the width direction is longer than the length in the width direction of the unvulcanized tread rubber part, In the cutting step, an excess portion of the extrusion molded product is cut off so that the length of the extrusion molded product in the width direction coincides with the length of the unvulcanized tread rubber part in the width direction. The method for manufacturing a tire according to any one of claims 1 to 5.

7. an extrusion molding device that includes a die plate having holes formed therein through which unvulcanized rubber is extruded, and that molds an extrusion-molded product of the unvulcanized rubber having a cross-sectional shape corresponding to the holes; a cutting device including a cutter that cuts the extrusion molded product molded by the extrusion molding device and a control device that controls the movement of the cutter; the die plate is configured to mold the extrusion larger than a predetermined unvulcanized tread rubber part; the control device controls the movement of the cutter based on the shape of the unvulcanized tread rubber part to cut off an excess portion of the extrusion-molded product, thereby forming the unvulcanized tread rubber part; The die plate is configured to form a reference portion serving as a positional reference in the extrusion molded product, a measuring device for measuring the position of the reference portion; and a calculation device that calculates a movement of the cutter by the control device based on the position of the reference portion measured by the measurement device. Manufacturing equipment for unvulcanized tread rubber parts.

8. An extrusion molding device comprising a die plate having holes formed therein through which unvulcanized rubber is extruded, and for molding an extrusion molded product of unvulcanized rubber having a cross-sectional shape corresponding to the holes; a cutting device including a cutter that cuts the extrusion molded product molded by the extrusion molding device and a control device that controls the movement of the cutter; the die plate is configured to mold the extrusion larger than a predetermined unvulcanized tread rubber part; the control device controls the movement of the cutter based on the shape of the unvulcanized tread rubber part to cut off an excess portion of the extrusion-molded product, thereby forming the unvulcanized tread rubber part; The unvulcanized tread rubber part is a tread surface extending in an extrusion direction in which the unvulcanized rubber is extruded and in a width direction perpendicular to the extrusion direction; A back surface of the tread surface; a flat plate-like shape including an inclined surface formed at an end in the width direction and connected to the back surface at a predetermined angle; the die plate is configured to mold the extrusion-molded product having the tread surface, the back surface, and an excess portion provided so as to cover the inclined surface, the control device controls the movement of the cutter to cut off an excess portion covering the inclined surface, thereby forming the inclined surface. Manufacturing equipment for unvulcanized tread rubber parts.

9. In the unvulcanized tread rubber part, the predetermined angle between the back surface and the inclined surface is set to an acute angle, The die plate is configured to mold the extrusion molded product such that an excess portion covering the inclined surface forms a right angle or an obtuse angle with the back surface.

9. The apparatus for manufacturing an unvulcanized tread rubber part according to claim 8.

10. the unvulcanized tread rubber part includes a thickness adjusting surface connected to the inclined surface and the tread surface, the thickness adjusting surface is set so that a height of a boundary portion between the thickness adjusting surface and the inclined surface with respect to the rear surface is a predetermined height, the die plate is configured to mold the extrusion molded product having an excess portion provided so as to cover the thickness adjustment surface; the control device controls the movement of the cutter to cut off an excess portion covering the thickness adjustment surface, thereby forming the thickness adjustment surface.

10. The apparatus for manufacturing an unvulcanized tread rubber part according to claim 8 or 9.

11. The die plate is configured to form a reference portion serving as a positional reference in the extrusion molded product, a measuring device for measuring the position of the reference portion; and a calculation device that calculates a movement of the cutter by the control device based on the position of the reference portion measured by the measurement device. The apparatus for manufacturing an unvulcanized tread rubber part according to any one of claims 8 to 10.

12. the unvulcanized tread rubber part has a flat plate shape extending in an extrusion direction in which the unvulcanized rubber is extruded and in a width direction perpendicular to the extrusion direction, the die plate is configured to mold the extrusion-molded product in a flat plate shape extending in the extrusion direction and the width direction, and having a length in the width direction longer than a length in the width direction of the unvulcanized tread rubber part, the control device controls the movement of the cutter to cut off the excess portion of the extrusion molded product so that the length of the extrusion molded product in the width direction coincides with the length of the unvulcanized tread rubber part in the width direction. The manufacturing apparatus for an unvulcanized tread rubber part according to any one of claims 7 to 11.

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