Green tire molding method and green tire molding apparatus
By cutting and winding rubber sheets in a specific direction to form green tires, the problems of heavy production burden and high defect rate are solved, achieving more efficient production and a lower defect rate.
Patent Information
- Authority / Receiving Office
- JP · JP
- Patent Type
- Applications
- Current Assignee / Owner
- SUMITOMO RUBBER INDUSTRIES LTD
- Filing Date
- 2024-11-08
- Publication Date
- 2026-05-20
AI Technical Summary
Existing green tire molding methods suffer from heavy production burdens and high defect rates during the production process.
A rectangular or rhomboid rubber sheet is formed by cutting a long strip of rubber in a first direction into two intersecting directions, and then wrapping it around a cylinder so that the cut edges are aligned with the circumference of the cylinder. A ring is then formed through a joining step.
It reduces the burden on the production floor, lowers the defect rate, and improves production efficiency and product uniformity.
Smart Images
Figure 2026083988000001_ABST
Abstract
Description
Technical Field
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Means for Solving the Problems
[0008] The present invention relates to a method for forming a green tire, A rubber sheet preparation step involves preparing a strip-shaped rubber sheet that is long in the first direction and has a certain width, A cutting step of cutting the rubber sheet in a second direction intersecting the first direction to create rectangular or parallelogram-shaped rubber sheet pieces, A winding step in which the rubber sheet piece is wrapped around the cylindrical body such that the pair of edges of the rubber sheet piece cut in the second direction are aligned with the circumferential direction of the cylindrical body, The process includes a joining step of joining the rubber sheet pieces on the cylindrical body to form an annular body. [Effects of the Invention]
[0009] Since the green tire molding method of the present invention has the above configuration, it can reduce the burden on the production site while reducing the defect rate. [Brief explanation of the drawing]
[0010] [Figure 1] This flowchart shows the procedure of one embodiment of the green tire molding method of the present invention. [Figure 2] Figure 1 is a block diagram of a green tire molding apparatus for carrying out the green tire molding method. [Figure 3] Figure 1 shows the rubber sheet preparation process, and Figure 2 shows the rubber sheet supply section in a perspective view. [Figure 4] Figure 1 shows the cutting process, and Figure 2 shows a perspective view of the cut section. [Figure 5] This is a perspective view showing a different form of cutting process and cut section than that shown in Figure 4. [Figure 6] Figure 1 shows the winding process, and Figure 2 shows the winding section in a perspective view. [Figure 7] This is a perspective view showing a different configuration of the winding process and winding section from Figure 6. [Figure 8] Figure 1 shows the jointing process, and Figure 2 shows the joint section from a perspective view. [Figure 9]FIG. 8 is a perspective view showing a joint process and a joint portion in another form. [Figure 10] FIG. 3 is a perspective view showing one form of a rubber sheet preparation process and a rubber sheet supply section. [Figure 11] FIG. 6 is a perspective view showing a modified example of the rubber sheet preparation process. [Figure 12] FIG. 9 is a side view showing a winding process as viewed from the axial direction of the cylindrical body. [Figure 13] FIG. 12 is a side view showing a modified example of the winding process. [Figure 14] FIG. 15 is a plan view showing the shape of a rubber sheet piece when the cutting angle θ, which is the angle of the second direction with respect to the first direction, is changed. [Figure 15] FIG. 18 is a flowchart showing the procedure of a modified example of a green tire forming method. [Figure 16] FIG. 21 is a flowchart showing the procedure of another modified example of a green tire forming method. [Figure 17] FIG. 24 is a flowchart showing the procedure of yet another modified example of a green tire forming method. [Figure 18] FIG. 27 is a plan view showing a composite body formed by laminating a carcass ply on a rubber sheet piece. [Figure 19] FIG. 30 is a side view showing the winding process of the green tire forming method of FIG. 17.
BEST MODE FOR CARRYING OUT THE INVENTION
[0011] Hereinafter, an embodiment of the present invention will be described based on the drawings. It should be understood that the drawings include exaggerated expressions and expressions different from the actual structural dimensional ratios in order to assist in understanding the content of the invention. Also, throughout each embodiment, the same or common elements are given the same reference numerals, and duplicate explanations are omitted. Furthermore, the specific configurations shown in the embodiments and the drawings are for understanding the content of the present invention, and the present invention is not limited to the specific configurations shown.
[0012] Figure 1 is a flowchart of the green tire molding method 100 of this embodiment. The green tire molding method 100 is a method for manufacturing a toroidal green tire. The green tire molding method 100 includes a rubber sheet preparation step S1, a cutting step S2, a winding step S3, and a jointing step S4.
[0013] Figure 2 shows a green tire molding apparatus 1 for performing the green tire molding method 100. The green tire molding apparatus 1 includes a rubber sheet supply unit 11, a cutting unit 12, a winding unit 13, and a joint unit 14.
[0014] The rubber sheet preparation process S1 is performed by the rubber sheet supply unit 11, etc. The cutting process S2 is performed by the cutting unit 12. The winding process S3 is performed by the winding unit 13. The jointing process S4 is performed by the joint unit 14.
[0015] Figure 3 shows the rubber sheet preparation process S1 and the rubber sheet supply unit 11. The rubber sheet preparation process S1 is a process for preparing a strip-shaped rubber sheet G1. The rubber sheet G1 prepared in this rubber sheet preparation process S1 is long in the first direction D1 and has a constant width L0. The width L0 is measured in a direction perpendicular to the first direction D1.
[0016] The rubber sheet G1 is made of an air-impermeable rubber composition suitable, for example, for the inner liner rubber of a tire. The rubber sheet G1 may be made of a rubber composition suitable for other components.
[0017] The rubber sheet G1 is prepared, for example, wound on a roll 11a. Such a rubber sheet G1 can be supplied to the cutting section 12, etc., while being pulled out in the first direction D1. The supply of the rubber sheet G1 is achieved by an applicator (not shown), such as a conveyor.
[0018] Figures 4 and 5 show the cutting process S2 and the cutting section 12. The cutting process S2 is a process of cutting the rubber sheet G1 in a second direction D2 that intersects the first direction D1. The second direction D2 may be a direction perpendicular to the first direction D1 (see Figure 4) or a direction that intersects the first direction D1 diagonally (see Figure 5).
[0019] For cutting, a cutter such as a rotary cutter or a push-type cutter is used. In other words, the cutting section 12 has a cutter 12a for cutting the rubber sheet G1.
[0020] In cutting process S2, the rubber sheet G1 is cut multiple times in a straight line. Between each cut, the rubber sheet G1 is fed out in the first direction D1 by a length L1. This creates a rectangular (including square) or parallelogram (including rhombus) shaped rubber sheet piece G2. A pair of parallel edges E1 are formed at the front and rear ends of the rubber sheet piece G2 in the first direction D1, created by the cutting. The distance L3 between the edges E1 is a function of the length L1 that the rubber sheet G1 is fed out in the first direction D1 between each cut, i.e., the cutting interval L1.
[0021] As shown in Figure 4, when the rubber sheet G1 is cut in a second direction D2 perpendicular to the first direction D1, a rectangular piece of rubber sheet G2 is created, and the length L2 of the rubber sheet piece G2 in the second direction D2 is equal to the width L0 of the rubber sheet G1. Also, the distance L3 between the edges E1 is equal to the cutting interval L1.
[0022] As shown in Figure 5, when cutting the rubber sheet G1 in a second direction D2 that intersects the first direction D1 diagonally, a parallelogram-shaped piece of rubber sheet G2 is created. If the angle between the second direction D2 and the first direction D1 (i.e., the cutting angle of the rubber sheet G1) is θ, then the length of the rubber sheet piece G2 in the second direction D2 is L2 = L0 / sinθ. Also, the distance between the edges E1 is L3 = L1sinθ.
[0023] Figures 6 and 7 show the winding process S3 and the winding section 13. The winding process S3 is the process of winding the rubber sheet piece G2 onto the cylindrical body 13a. That is, the winding section 13 has a cylindrical body 13a, also called a molding drum. The cylindrical body 13a is rotatably supported around its support axis. The supply of the rubber sheet piece G2 to the cylindrical body 13a is achieved by an applicator (not shown) such as a conveyor.
[0024] In the winding process S3, the rubber sheet piece G2 is supplied in a direction parallel to the edge E1 (second direction) and wound around the rotating cylindrical body 13a. As a result, the rubber sheet piece G2 is wound so that the pair of edges E1 are aligned with the circumferential direction of the cylindrical body 13a.
[0025] Figure 6 shows the configuration in which, in the cutting process S2 of Figure 4, the rubber sheet piece G2, cut in the second direction D2 perpendicular to the first direction D1, is supplied to the cylindrical body 13a and wound around it. In this configuration, the starting end E3 (see Figure 8) and ending end E4 of the wound rubber sheet piece G2 are arranged parallel to the axial direction of the cylindrical body 13a.
[0026] Figure 7 shows the configuration in which, in the cutting process S2 of Figure 5, the rubber sheet G1, cut in a second direction D2 that intersects the first direction D1 at an angle, is supplied to the cylindrical body 13a and wound around it. In this configuration, the starting end E3 (see Figure 9) and ending end E4 of the wound rubber sheet piece G2 are positioned at an angle to the axial direction of the cylindrical body 13a.
[0027] Figures 8 and 9 show the joint process S4 and the joint section 14. The joint process S4 is the process of joining the starting end E3 and the ending end E4 of the rubber sheet piece G2. For example, a joint roller 14a is used to join the rubber sheet piece G2. That is, the joint section 14 has a joint roller 14a.
[0028] The joint roller 14a moves parallel to the starting end E3 and ending end E4 of the rubber sheet piece G2, pressing against the ending end E4. By pressing the joint roller 14a against the joint portion between the starting end E3 and ending end E4 of the rubber sheet piece G2 on the cylindrical body 13a, the rubber sheet piece G2 is joined, forming an annular body G3 that constitutes part of the green tire.
[0029] Figure 8 shows a configuration in which the rubber sheet pieces G2, cut in the second direction D2 perpendicular to the first direction D1, are joined on the cylindrical body 13a during the cutting process S2 of Figure 4. In this configuration, the starting end E3 and ending end E4 of the winding of the rubber sheet pieces G2 are arranged parallel to the axial direction of the cylindrical body 13a.
[0030] Figure 9 shows a configuration in which the rubber sheet G1, cut in the second direction D2 which intersects the first direction D1 diagonally in the cutting process S2 of Figure 5, is joined on the cylindrical body 13a. In this configuration, the starting end E3 and ending end E4 of the winding of the rubber sheet piece G2 are positioned diagonally with respect to the axial direction of the cylindrical body 13a.
[0031] The green tire molding method 100 and green tire molding apparatus 1 of the present invention have the above configuration, so by adjusting the cutting interval L1 of the rubber sheet pieces 2 and the angle θ of the second direction D2 with respect to the first direction D1, multiple sizes of rubber sheet pieces G2 can be formed from one type of rubber sheet G1. Since these rubber sheet pieces G2 correspond to multiple sizes of green tires, it is possible to reduce the burden on the production site.
[0032] As shown in Figures 4 and 5, it is desirable that the rubber sheet G1 has tapered portions 21 at both ends E2 in the width direction, where the thickness gradually decreases toward the outside in the width direction. As shown in Figures 6, 7, 8, and 9, these ends E2 become the starting end E3 and ending end E4 of the winding of the rubber sheet piece G2.
[0033] Then, in the jointing process S4 shown in Figures 8 and 9, the tapered portions 21 of the rubber sheet pieces 2 are joined together by overlapping them. This suppresses variations in the thickness of the rubber sheet pieces 2 at the joint, improves the uniformity of the circumferential weight, and enhances the uniformity performance of the finished tire. In addition, steps at the joint are suppressed, and defects such as air pockets are suppressed. Consequently, the defect rate of green tires and ultimately finished tires is reduced, further reducing the burden on the production site. Furthermore, excessive weight at the joint is suppressed, making it easier to lighten the finished tire.
[0034] Figure 10 shows one configuration of the rubber sheet preparation process S1 and the rubber sheet supply unit 11. The rubber sheet preparation process S1 further includes an extrusion process S11. The rubber sheet supply unit 11 further includes an extrusion unit 11b.
[0035] The extrusion process S11 is a process for extruding the rubber sheet G1 with a uniform cross-section. The extrusion process S11 is performed by the extrusion unit 11b. The extrusion unit 11b consists of, for example, a screw (not shown) for extruding while kneading the rubber composition, a die plate 11c provided at the rear end of the extrusion unit 11b, and rollers 11d arranged opposite the die plate 11c.
[0036] The die plate 11c has an outlet 11e that corresponds to the extrusion cross-section of the rubber sheet G1. In this embodiment, the outlet 11e is formed for extruding the rubber sheet G1, which has tapered portions 21 at both ends E2 in the width direction.
[0037] The rubber sheet G1 extruded from the die plate 11c is wound onto the roll 11a and transferred to the rubber sheet supply unit 11 shown in Figure 3. The first direction D1 relative to the rubber sheet G1 coincides with the extrusion direction of the rubber sheet G1. Alternatively, the rubber sheet G1 may be supplied directly from the die plate 11c to the cutting unit 12 without being wound onto the roll 11a.
[0038] This extrusion process S11 makes it possible to easily prepare a continuous rubber sheet G1 with the same cross-section and supply it to the cutting section 12.
[0039] As shown in Figure 10, the die plate 11c of this embodiment may have protrusions 11f formed on the surface of the rubber sheet G1 for forming grooves 22. The protrusions 11f project inward toward the outlet 11e. The protrusions 11f facilitate the formation of grooves 22 continuous in the first direction D1 on the surface of the rubber sheet G1 as it is extruded from the outlet 11e.
[0040] The grooves 22 facilitate the expulsion of air trapped inside the green tire during the green tire molding process. In other words, the grooves 22 function as passages for air that is expelled to the outside during the green tire molding and vulcanization processes.
[0041] The die plate 11c may have recesses (not shown) in place of, or in addition to, the protrusions 11f. The recesses form protrusions on the surface of the rubber sheet G1 that are continuous in the first direction D1. The area around the protrusions functions as a passage for air to be discharged to the outside during the molding and vulcanization processes of the green tire, similar to the grooves 22 described above.
[0042] As shown in Figure 11, in the rubber sheet preparation step S1, a calendering step S12 may be applied instead of the extrusion step S11 in Figure 10. In the calendering step S12, a roller 11g with an equivalent outlet 11h is applied instead of the die plate 11c. The roller 11g has convex portions 11i that are continuous in the circumferential direction. In this embodiment, the convex portions 11i are formed to meander in the axial direction. Such convex portions 11i easily form grooves 22 on the surface of the rubber sheet G1 that meander and are continuous in the first direction D1. The roller 11g may have concave portions (not shown) instead of, or in addition to, the convex portions 11i.
[0043] Figure 12 shows the winding process S3 viewed from the axial direction of the cylindrical body 13a. In the winding process S3 of the form shown in Figure 12, a single rubber sheet piece G2 is wound around the circumference of the cylindrical body 13a, and the end portion E4 and the starting end portion E3 are joined together. Such a rubber sheet piece G2 can be realized by setting the length L2 in the second direction D2 of the rubber sheet piece G2 cut in the cutting process S2 to be large enough to match the circumference of the cylindrical body 13a. With such a winding process S3, the production efficiency of green tires can be easily increased.
[0044] Figure 13 shows a modified example of the winding process S3. In the winding process S3 shown in Figure 13, multiple rubber sheet pieces G2 are wound in series around the circumference of the cylindrical body 13a. Such rubber sheet pieces G2 can be realized by setting the length L2 of the second direction D2 of the rubber sheet pieces G2 cut in the cutting process S2 to a value obtained by dividing the circumference of the cylindrical body 13a by an integer. With such a winding process S3, the rubber sheet supply unit 11 and, consequently, the green tire molding apparatus 1 can be made into a compact configuration.
[0045] In the winding process S3 shown in Figure 13, the end portion E4 of the first wound rubber sheet piece G2 is sequentially joined to the starting portion E3 of the next wound rubber sheet piece G2. Finally, the end portion E4 of the last wound rubber sheet piece G2 is joined to the starting portion E3 of the first wound rubber sheet piece G2, forming an annular body G3.
[0046] Figure 14 shows the shape of the rubber sheet piece G2 when the cutting angle θ, which is the angle between the second direction D2 and the first direction D1, is changed. The rubber sheet piece G2 when the cutting angle θ is 90° is represented by a solid line, the rubber sheet piece G2 when the cutting angle θ is θ' is represented by a dashed line, the rubber sheet piece G2 when the cutting angle θ is θ'' is represented by a dashed line, and the rubber sheet piece G2 when the cutting angle θ is θ''' is represented by a dashed line.
[0047] As already mentioned, when the cutting angle θ is 90°, a rectangular rubber sheet piece G2 is formed. When the cutting angle θ is less than 90°, such as θ', θ'', or θ''', a parallelogram-shaped rubber sheet piece G2 is formed. As the cutting angle θ decreases, the lengths L2', L2'', L2'' of the rubber sheet piece G2 in the second direction D2', D2'', D2'' increase. Therefore, by changing the cutting angle θ, the lengths L2, L2', L2'', L2'''' of the rubber sheet piece G2 in the second direction can be adjusted according to the circumference of the cylindrical body 13a.
[0048] The circumference of the cylindrical body 13a is typically set according to the rim diameter of the finished tire. By changing the cutting angle θ, multiple sizes of rubber sheet pieces G2 applicable to multiple sizes of finished tires with different rim diameters can be formed from a single rubber sheet G1.
[0049] Figure 15 is a flowchart of the green tire molding method 100A, which is a modified version of the green tire molding method 100. For parts of the green tire molding method 100A that are not described below, the configuration of the green tire molding method 100 described above may be adopted.
[0050] The green tire molding method 100A differs from the green tire molding method 100 described above in that it further includes a size data acquisition step S5. The size data acquisition step S5 acquires data relating to the size of the green tire to be molded. The data includes, for example, data corresponding to the rim diameter of the finished tire. The above data may also include data relating to the circumference of the cylindrical body 13a.
[0051] The size data acquisition step S5 is implemented, for example, by a computer device connected to the green tire molding method 100. The computer device is connected by wired or wireless connection to a database in which data on the size of green tires is stored. The database may be built on the computer device's own storage means. The computer device acquires data on the size of green tires by accessing the database.
[0052] The method applied to the size data acquisition process S5 is not limited to those described above. For example, it may be a method in which an operator inputs data regarding the size of the green tire into the green tire molding method 100.
[0053] The size data acquisition step S5 is performed prior to the cutting step S2. Therefore, the size data acquisition step S5 is performed before the rubber sheet preparation step S1, simultaneously with the rubber sheet preparation step S1, or immediately after the rubber sheet preparation step S1.
[0054] Then, in the cutting process S2 of the raw tire molding method 100A, the cutting angle change process S21 is performed prior to the cutting of the rubber sheet G1. That is, the cutting process S2 includes the cutting angle change process S21. After the cutting angle change process S21, the process S25 for cutting the rubber sheet G1 is performed.
[0055] In the cutting angle changing process S21, the cutting angle θ, which is the angle between the second direction D2 and the first direction D1, is determined by the CPU of the computer device based on the data regarding the rim diameter of the finished tire acquired in the size data acquisition process S5. The CPU of the computer device then transmits information regarding the determined cutting angle θ to the cutting unit 12, and the cutting angle θ is changed. The change in the cutting angle θ is achieved by changing the angle of the supply direction of the rubber sheet G1 (first direction D1) relative to the cutting direction (second direction D2) by the cutter 12a. This makes it possible to mold multiple sizes of green tires with different rim diameters without changing the rubber sheet G1. Furthermore, the positional relationship between the cutter 12a and the cylindrical body 13a can be kept constant, eliminating the need for angle adjustment of the rubber sheet pieces G2 after cutting.
[0056] In the cutting angle changing process S21, the cutting angle θ is changed when the cylindrical body 13a used in the winding process S3 is changed. In other words, the cutting angle θ is changed when forming a green tire with a different inner diameter (corresponding rim diameter of the finished tire).
[0057] Figure 15 is a flowchart of green tire molding method 100B, which is another modified example of green tire molding method 100. For parts of green tire molding method 100B that are not described below, the configurations of green tire molding methods 100 and 100A described above may be adopted.
[0058] The green tire molding method 100B is the same as the green tire molding method 100 described above, in that it further includes a size data acquisition step S5. In the green tire molding method 100B, the data acquired in the size data acquisition step S5 includes, for example, data relating to the profile of the finished tire (especially the inner peripheral).
[0059] When the rubber sheet piece G2 is applied to the inner liner of a tire, the width of the rubber sheet piece G2 wrapped around the cylindrical body 13a is typically set according to the inner peripheral of the finished tire.
[0060] As shown in Figures 4 and 6, when cutting in the cutting process S2 in a second direction D2 perpendicular to the first direction D1, the cutting interval L1 corresponds to the width of the rubber sheet piece G2 wrapped around the cylindrical body 13a (the axial length of the cylindrical body 13a). Also, as shown in Figures 5 and 7, when cutting in the cutting process S2 in a second direction D2 obliquely intersecting the first direction D1, the distance L3 between the edges E1 corresponds to the width of the rubber sheet piece G2 wrapped around the cylindrical body 13a. In this case, the distance L3 between the edges E1 depends on the cutting interval L1.
[0061] Therefore, as shown in Figure 16, in the cutting step S2 of the raw tire molding method 100B, a cutting interval changing step S22 is performed to change the cutting interval L1 prior to cutting the rubber sheet G1. In other words, the cutting step S2 includes the cutting interval changing step S22.
[0062] In the cutting interval change process S22, the cutting interval L1 of the rubber sheet pieces G2 is determined and changed based on the data regarding the inner peripheral of the finished tire acquired in the size data acquisition process S5. The change in the cutting interval L1 is achieved by changing the amount of rubber sheet G1 fed in the first direction D1 between each cutting.
[0063] Then, after the cutting interval change process S22, the process S25 for cutting the rubber sheet G1 is performed. As a result, the cutting interval L1 is changed according to the inner peripheral of the finished tire, and multiple types of rubber sheet pieces G2 of different sizes that can be applied to multiple sizes of finished tires with different profiles are formed from one type of rubber sheet G1.
[0064] Figure 17 is a flowchart of green tire molding method 100C, which is yet another modification of green tire molding method 100. For parts of green tire molding method 100C not described below, the configurations of green tire molding methods 100, 100A, and 100B described above may be adopted.
[0065] The green tire molding method 100C differs from the green tire molding method 100 described above in that it further includes a lamination step S6. In the lamination step S6, a carcass ply 3 is laminated onto the rubber sheet piece G2 created in the cutting step S2 to form a composite 4 (see Figure 17).
[0066] In the green tire molding method 100C, the rubber sheet piece G2 and the carcass ply 3 are wrapped together simultaneously, thus improving the productivity of green tires.
[0067] Figure 18 shows a composite 4 formed by laminating a carcass ply 3 onto a rubber sheet piece G2. The carcass ply 3 is a layer that constitutes the carcass layer of the tire, and is formed by covering an array of multiple carcass cords 3a arranged parallel to each other with topping rubber 3b (see Figure 19).
[0068] The carcass ply 3 is laminated with respect to the rubber sheet piece G2, offset in the second direction D2. This facilitates the joining of the rubber sheet piece G2.
[0069] In the lamination process S6, the carcass ply 3 is laminated such that the carcass cord 3a is perpendicular to the second direction D2.
[0070] As shown in Figure 18, it is desirable that the rubber sheet piece G2 be cut in a second direction D2 that intersects the first direction D1 (see Figures 5 and 7) at an angle. It is also desirable that grooves 22 (see Figures 10 and 11) be formed on the surface of the rubber sheet piece G2.
[0071] When the carcass plies 3 are laminated so that the carcass cords 3a are perpendicular to the second direction D2, the grooves 22 intersect the carcass cords 3a at an angle. This facilitates the expulsion of air trapped between the carcass plies 3 and the rubber sheet pieces G2 to the outside, suppressing defects such as air pockets.
[0072] Figure 19 shows the winding process S3 in the green tire molding method 100C. In the winding process S3, the rubber sheet piece G2, i.e., the composite 4, on which the carcass ply 3 is laminated, is wound around the cylindrical body 13a and joined. At this time, since the carcass ply 3 is laminated with respect to the rubber sheet piece G2 with a position shifted in the second direction D2, the rubber sheet piece G2 is joined by the winding of the carcass ply 3. This improves the productivity of green tires.
[0073] Although the method for forming a green tire of the present invention has been described in detail above, the present invention is not limited to the specific embodiments described above and can be implemented in various modified forms.
[0074] [Note] The present invention includes the following embodiments.
[0075] [Invention 1] A method for forming a raw tire, A rubber sheet preparation step involves preparing a strip-shaped rubber sheet that is long in the first direction and has a certain width, A cutting step of cutting the rubber sheet in a second direction intersecting the first direction to create rectangular or parallelogram-shaped rubber sheet pieces, A winding step in which the rubber sheet piece is wrapped around the cylindrical body such that the pair of edges of the rubber sheet piece cut in the second direction are aligned with the circumferential direction of the cylindrical body, The process includes a joining step of joining the rubber sheet pieces on the cylindrical body to form an annular body, Method for forming raw tires. [Invention 2] The rubber sheet has tapered sections at both ends in the width direction, where the thickness gradually decreases towards the outside in the width direction. The method for forming a green tire according to the present invention 1, wherein the jointing step involves overlapping and joining the tapered portions of the rubber sheet pieces. [Invention 3] The method for forming a green tire according to the present invention 1 or 2, wherein the rubber sheet preparation step further includes an extrusion step for extruding the rubber sheet in the same cross-section. [4th Invention] The method for forming a green tire according to the present invention, wherein the extrusion step includes a step of forming grooves or protrusions continuous in the first direction on the surface of the rubber sheet. [5th Invention] The method for forming a green tire according to any one of invention 1 to 4, wherein in the winding step, one piece of rubber sheet is wound around the circumference of the cylindrical body. [Invention 6] The method for forming a green tire according to any one of invention 1 to 4, wherein in the winding step, a plurality of rubber sheet pieces are wound in series around the circumference of the cylindrical body. [7th Invention] Prior to the aforementioned cutting process, the process further includes a size data acquisition step for acquiring data relating to the size of the green tire to be molded, The method for forming a green tire according to any one of invention 1 to 6, wherein the cutting step includes a cutting angle changing step that changes the cutting angle, which is the angle of the second direction relative to the first direction, based on the acquired data. [8th Invention] Prior to the aforementioned cutting process, the process further includes a size data acquisition step for acquiring data relating to the size of the green tire to be molded, The method for forming a green tire according to any one of invention 1 to 7, wherein the cutting step includes a cutting interval changing step that changes the cutting interval of the rubber sheet based on the acquired data. [Invention 9] The rubber sheet constitutes the inner liner rubber, according to the method for molding a green tire according to any one of claims 1 to 8 of the present invention. [Invention 10] A method for forming a green tire according to any one of invention 1 to 9, further comprising a lamination step of laminating a carcass ply onto the rubber sheet piece created in the cutting step. [Invention 11] A green tire molding apparatus, A rubber sheet supply unit that supplies a strip-shaped rubber sheet that is long in the first direction and has a certain width, A cutting unit that cuts the rubber sheet in a second direction intersecting the first direction to create rectangular or parallelogram-shaped rubber sheet pieces, The pair of edges of the rubber sheet piece cut in the second direction are arranged to form a winding portion that wraps the rubber sheet piece around the cylindrical body so that it follows the circumferential direction of the cylindrical body, The cylindrical body includes a joint portion that joins the rubber sheet pieces to form an annular body, A machine for forming green tires. [Explanation of Symbols]
[0076] 1: Green tire molding machine 2: Rubber sheet piece 3: Carcass ply 11: Rubber sheet supply unit 12: Cutting section 13: Wrapping section 13a: Cylindrical body 14: Joint section 21: Tapered section 22: Groove 100: Method for forming raw tires 100A: Method for forming green tires 100B: Method for forming raw tires 100C: Raw tire molding method D1: 1st direction D2 :Second direction E1: Edge E2: Both ends G1: Rubber sheet G2: Rubber sheet piece G3: Ring-shaped body L0: Width L1: Cutting interval S1: Rubber sheet preparation process S11: Extrusion process S2: Cutting process S21: Cutting angle change process S22: Cutting interval change process S3: Wrapping process S4: Joint process S5: Size data acquisition process S6:Lamination process θ: Cutting angle
Claims
1. A method for forming a raw tire, A rubber sheet preparation step involves preparing a strip-shaped rubber sheet that is long in the first direction and has a certain width, A cutting step of cutting the rubber sheet in a second direction intersecting the first direction to create rectangular or parallelogram-shaped rubber sheet pieces, A winding step in which the rubber sheet piece is wrapped around the cylindrical body such that the pair of edges of the rubber sheet piece cut in the second direction are aligned with the circumferential direction of the cylindrical body, The process includes a joining step of joining the rubber sheet pieces on the cylindrical body to form an annular body, Method for forming raw tires.
2. The rubber sheet has tapered sections at both ends in the width direction, where the thickness gradually decreases towards the outside in the width direction. The method for forming a green tire according to claim 1, wherein the jointing step involves overlapping and joining the tapered portions of the rubber sheet pieces.
3. The method for forming a green tire according to claim 1, wherein the rubber sheet preparation step further includes an extrusion step for extruding the rubber sheet in the same cross-section.
4. The method for forming a green tire according to claim 3, wherein the extrusion step includes a step of forming grooves or protrusions continuous in the first direction on the surface of the rubber sheet.
5. The method for forming a green tire according to claim 1, wherein in the winding step, one piece of the rubber sheet is wound around the circumference of the cylindrical body.
6. The method for forming a green tire according to claim 1, wherein in the winding step, a plurality of rubber sheet pieces are wound in series around the circumference of the cylindrical body.
7. Prior to the aforementioned cutting process, the process further includes a size data acquisition step for acquiring data relating to the size of the green tire to be molded, The method for forming a green tire according to claim 1, wherein the cutting step includes a cutting angle changing step in which the cutting angle, which is the angle of the second direction with respect to the first direction, is changed based on the acquired data.
8. Prior to the aforementioned cutting process, the process further includes a size data acquisition step for acquiring data relating to the size of the green tire to be molded, The method for forming a green tire according to claim 1, wherein the cutting step includes a cutting interval changing step that changes the cutting interval of the rubber sheet based on the acquired data.
9. The method for molding a green tire according to claim 1, wherein the rubber sheet constitutes the inner liner rubber.
10. A method for forming a green tire according to any one of claims 1 to 9, further comprising a lamination step of laminating a carcass ply onto the rubber sheet piece created in the cutting step.
11. A green tire molding apparatus, A rubber sheet supply unit that supplies a strip-shaped rubber sheet that is long in the first direction and has a certain width, A cutting unit that cuts the rubber sheet in a second direction intersecting the first direction to create rectangular or parallelogram-shaped rubber sheet pieces, The pair of edges of the rubber sheet piece cut in the second direction are arranged to form a winding portion that wraps the rubber sheet piece around the cylindrical body so that it follows the circumferential direction of the cylindrical body, The cylindrical body includes a joint portion that joins the rubber sheet pieces to form an annular body, A machine for forming green tires.