Method for manufacturing pneumatic tire and system for manufacturing pneumatic tire

Abstract

To provide a method and system for manufacturing a pneumatic tire that are capable of reducing an occurrence of defect during molding by appropriately calculating a distance for moving a chuck that holds a bead.SOLUTION: A method for manufacturing a pneumatic tire includes the steps of: calculating a first distance L1; and changing a first state in which a pair of beads 1 of a first case body T1 are held by a pair of chucks 510 to a second state in which a distance between the pair of beads 1 is shortened by the first distance L1 while expanding the first case body T1. The first distance L1 is calculated based on a tire axial dimension L3 of a belt 6, a separation distance L0 along a tire axial direction AD of the pair of beads 1 in the first state, information regarding a rise height H1 along a tire radial direction RD from an inner end P2 of the bead 1 to an outer end P1 of the belt 6 in the second state, and a rise angle θ from the inner end P2 of the bead 1 toward the outer end P1 of the belt 6 in the second state.SELECTED DRAWING: Figure 7

Description

Technical Field

[0001] The present disclosure relates to a method for manufacturing a pneumatic tire and a manufacturing system for a pneumatic tire.

Background Art

[0002] A pneumatic tire is manufactured by integrating a first case body formed by molding a plurality of tire members such as a carcass, and a second case body formed by molding a plurality of tire members such as tread rubber and a belt, into one green tire (uncured tire), and then heating and pressurizing the green tire in a mold for vulcanization molding (see Patent Document 1).

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] The process of forming the first case body T1 and the second case body T2 into one green tire will be described with reference to FIG. 9. As shown in FIG. 9, a pair of beads 1 of the first case body T1 before inflation are held by a pair of chucks 510 of a molding device (first state). Thereafter, while inflating the first case body T1, there is a step of moving the pair of chucks 510 closer to each other from the first state to integrate the first case body T1 and the second case body T2.

[0005] In order to realize this process, it is necessary to specify the initial separation distance L0 (also called the case set width) along the tire axis direction AD of the pair of beads 1 in the first state to the molding device. Further, it is necessary to specify the approaching width L1 indicating the distance by which the pair of chucks 510 are moved inward in the tire axis direction from the first state to the molding device.

[0006] In a state where a pair of chucks 510 have been moved inward in the tire axial direction, if the rising angle from the inner end of the bead 1 toward the outer end of the belt is appropriate, it is possible to suppress air from entering between the first case body T1 and the second case body T2. However, even if the rising angle is a constant angle, since the above-mentioned pulling width varies according to the tire size, the operator has not been able to appropriately specify the pulling width for setting the above-mentioned rising angle to a specified angle with respect to the molding apparatus.

[0007] The present disclosure provides a method and a manufacturing system for pneumatic tires that can appropriately calculate the distance for moving a chuck that holds a bead, and reduce the occurrence of defects during molding.

Means for Solving the Problems

[0008] The method for manufacturing a pneumatic tire according to the present disclosure includes a step of winding a plurality of tire members including a carcass around a carcass band drum to generate a cylindrical first case body having a pair of beads, a step of winding a plurality of tire members including tread rubber and a belt around a belt drum to generate a cylindrical second case body, a step of calculating a first distance, and a step of moving the pair of chucks inward in the tire axial direction while inflating the first case body from a first state in which the pair of beads of the first case body are respectively held by a pair of chucks to a second state in which the distance between the pair of chucks is made shorter by the first distance, and integrating the first case body and the second case body. The step of calculating the first distance calculates the first distance based on the tire axial dimension of the belt, the initial separation distance along the tire axial direction of the pair of beads in the first state, information on the rising height along the tire radial direction from the inner end of the bead to the outer end of the belt in the second state, and the rising angle from the inner end of the bead to the outer end of the belt in the second state.

[0009] The manufacturing system of the pneumatic tire of the present disclosure includes a carcass band drum in which a plurality of tire members including a carcass are wound to generate a cylindrical first case body having a pair of beads, a belt drum in which a plurality of tire members including tread rubber and a belt are wound to generate a cylindrical second case body, a pair of chucks capable of holding the pair of beads, and a calculation system for calculating a first distance. From a first state in which the pair of beads of the first case body are respectively held by the pair of chucks, while inflating the first case body, the pair of chucks are moved inward in the tire axial direction to shorten the distance between the pair of chucks to the first distance, and the first case body and the second case body are configured to be integratable. The calculation system calculates the first distance based on the tire axial dimension of the belt, the initial separation distance along the tire axial direction of the pair of beads in the first state, information on the rising height along the tire radial direction from the inner end of the bead to the outer end of the belt in the second state, and the rising angle from the inner end of the bead to the outer end of the belt in the second state.

Brief Description of the Drawings

[0010]

Figure 1

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Figure 9

Embodiments for Carrying Out the Invention

[0011] Hereinafter, a first embodiment of the present disclosure will be described with reference to the drawings.

[0012] [Structure of Green Tire T3 (Uncured Tire)] FIG. 1 is a tire meridian cross-sectional view schematically showing the structure of a green tire T3. In the figure, for ease of understanding, gaps are provided between some tire members for illustration. As shown in FIG. 1, the green tire T3 includes a pair of beads 1, sidewalls 2 extending radially outward RD1 of the tire diameter from each bead 1, and a tread 3 connecting the radially outer RD1 ends of the sidewalls 2. In the bead 1, an annular bead core 1a formed by rubber-coating a converging body such as a steel wire, a bead filler 1b made of hard rubber, and a chafer 1c covering around the bead core 1a are arranged. Further, the green tire T3 includes a toroidal carcass 4 arranged to span between the pair of beads 1 and reaching the bead 1 through the sidewall 2 from the tread 3. At least one carcass 4 is provided, and the end of the carcass 4 is locked in a state of being wound up via the bead core 1a. An inner liner 5 for maintaining air pressure is arranged on the inner peripheral side of the carcass 4. On the outer periphery of the carcass 4 in the tread 3, a plurality (two in this embodiment) of belts 6 for reinforcing the carcass 4 by the tag effect are arranged. The plurality of belts 6 each have a metal cord extending obliquely at a predetermined angle with respect to the tire circumferential direction. The plurality of belts 6 are laminated such that the metal cords cross each other in opposite directions. On the outer peripheral side of the plurality of belts 6, a belt reinforcing layer 7 having a non-metal cord such as a resin cord is arranged, and on the outer peripheral surface thereof, a tread rubber 8 is arranged. On the outer periphery of the carcass 4 in the sidewall 2, a sidewall rubber 9 forming the tire side surface is arranged. The pneumatic tire of the first embodiment has a SWOT (SideWall On Tread) structure in which the sidewall rubber 9 lies on the tread rubber 8.

[0013] [Method for manufacturing a pneumatic tire] The manufacturing method of a pneumatic tire includes a step of laminating a plurality of tire members to manufacture a green tire T3, and a step of heating and pressurizing the green tire T3 in a mold for vulcanization molding. The manufacturing method of the green tire T3 includes a step of molding a first case body T1, also called a first case, a step of molding a second case body T2, also called a second case, and a step of inflating the first case body T1 to combine it with the second case body T2 to obtain the green tire T3.

[0014] [Molding of the First Case Body T1 (First Case)] The step of molding the first case body T1 will be described with reference to FIG. 2. FIG. 2 is a diagram showing the molding process of the first case body T1. As shown in FIG. 2, an inner liner 5, a chafer 1c, a carcass 4, and a sidewall rubber 9 are wound around a carcass band drum 50. Thereafter, a bead filler 1b and a bead core 1a are arranged at both ends of the carcass 4 to mold the first case body T1. A release sheet (not shown) is arranged between the tip of the sidewall rubber 9 and the carcass 4, and a part of the tip of the sidewall rubber 9 can be peeled off from the carcass 4 by the release sheet. The molded first case body T1 is conveyed from the carcass band drum 50 to a molding device 51 (also called a shaving drum) by a carcass transfer 52 as shown in FIG. 3. FIG. 3 is a diagram showing the operations of the respective devices constituting the manufacturing system of the pneumatic tire.

[0015] [Molding of the Second Case Body T2 (Second Case)] The step of molding the second case body T2 will be described with reference to FIG. 4. FIG. 4 is a diagram showing the molding process of the second case body T2. As shown in FIG. 4, after a belt 6 and a belt reinforcing layer 7 (not shown in the figure) are wound around a belt drum 53, a tread rubber 8 is wound around the tire for one circumference to obtain the second case body T2. The molded second case body T2 is conveyed from the belt drum 53 to the molding device 51 by a belt transfer 54 as shown in FIG. 3.

[0016] [Combination of the First Case Body T1 and the Second Case Body T2] Figs. 5 and 6 are explanatory views regarding the process of integrating the first case body T1 and the second case body T2. As shown in Fig. 5, a pair of chucks 510 of the molding device 51 hold a pair of beads 1 of the first case body T1 (first state). In the first state, the separation distance between the beads 1 held by the pair of chucks 510 is set to the initial separation distance L0. The initial separation distance L0, also called the case set width, is the distance along the tire axial direction AD between the inner ends P2 (see Fig. 7; the ends on the inner side in the tire diameter direction and the inner side in the tire axial direction) of the pair of beads 1. In the first embodiment, the initial separation distance L0 (case set width) is manually input into the molding device 51 by the operator. The second case body T2 is held by the belt transfer 54 and is arranged in a state where the tire equatorial plane coincides with the outer side RD1 in the tire diameter direction of the first case body T1.

[0017] Next, the carcass 4 of the first case body T1 is wound up by a turn-up bladder (not shown), and as shown in Figs. 6 and 7, while inflating the first case body T1 with an inflate bladder (not shown), the pair of chucks 510 are moved inward in the tire axial direction AD to make the distance between the pair of chucks 510 shorter to a second state with a first distance L1 (also called the draw width). In the first embodiment, the first distance L1 (draw width) is manually input into the molding device 51 by the operator. Next, with the tip of the sidewall rubber 9 retracted outward in the tire axial direction AD, the second case body T2 is pressed against the first case body T1 by a stitcher (not shown), and then the release sheet is removed from the tip of the sidewall rubber 9, and the tip of the sidewall rubber 9 is pressed against the tread rubber 8 of the second case body T2. In this way, the second case body T2 and the first case body T1 are joined to form a green tire T3.

[0018] FIG. 8 is a diagram showing a manufacturing system for a pneumatic tire. The above process is carried out using the manufacturing system for a pneumatic tire shown in FIG. 8. As shown in FIG. 8, the manufacturing system includes a molding device 51 having a pair of chucks 510 and a calculation system 55. The calculation system 55 calculates the above first distance L1 (approach width). The calculation algorithm for the first distance L1 will be described later. As shown in FIG. 8, a production plan is output in a visible manner to the operator from the production execution system 56 at a predetermined timing (examples include printing on paper or displaying on a display). The production plan includes information on the tire to be produced and the production instruction quantity. The information on the tire to be produced includes the above initial separation distance L0 (case set width), the diameter φ1 of the belt drum 53 described later, the diameter φ2 of the carcass band drum 50, the tire axial dimension L3 of the belt 6, and the rising angle θ. A preferable rising angle θ for suppressing air entry between the first case body T1 and the second case body T2 is 65 degrees.

[0019] The operator inputs the above initial separation distance L0 (case set width), the diameter φ1 of the belt drum 53 described later, the diameter φ2 of the carcass band drum 50, the tire axial dimension L3 of the belt 6, and the rising angle θ to the calculation system 55. The calculation system 55 calculates the first distance L1 (approach width) based on the input information and outputs the first distance L1 (approach width) in a visible manner to the operator.

[0020] The operator inputs the initial separation distance L0 (case set width) and the first distance L1 (approach width) to the molding device 51 and executes the process of integrating the first case body T1 and the second case body T2.

[0021] <Calculation method of the first distance L1 (approach width)> The calculation system 55 calculates the first distance L1 (approach width) using the formula described below. L1 = L0 - L3 - {(φ1 - φ2) / tanθ} The above formula is calculated based on tanθ = {(φ1 - φ2) / 2} / {(L0 - L1 - L3) / 2} (see FIG. 7).

[0022] As information regarding the rising height H1 along the tire radial direction RD from the inner end P2 of the bead 1 to the outer end P1 of the belt 6 in the second state shown in FIG. 7, the diameter φ1 of the belt drum 53 and the diameter φ2 of the carcass band drum 50 can be used. This is because H1 can be calculated by the formula H1 = (φ1 - φ2) / 2.

[0023] The inner end P2 of the bead 1 is the angle at which the inner end in the tire radial direction and the inner end in the tire axial direction of the bead 1 intersect. The outer end P1 of the belt 6 is the outer end P1 in the tire axial direction AD of the belt 6.

[0024] In the first embodiment, the belt 6 serving as a specific reference for the rising height H1 is the first belt (counted as the first and second from the inner side to the outer side in the tire radial direction RD), but it is not limited to the first belt. For example, among the plurality of belts 6 having metal cords, the belt 6 with the longest tire axial length is targeted. The belt reinforcing layer 7 is not included in the belt 6. The same applies to the belt 6 serving as a specific reference for the rising angle θ described later. The same also applies to the belt 6 serving as a specific reference for the tire axial dimension L3 of the above belt 6.

[0025] The rising angle θ from the inner end P2 of the bead 1 toward the outer end P1 of the belt 6 can be calculated based on the tire cross-sectional height after tire vulcanization. Since the tire cross-sectional height after tire vulcanization is approximately the same as the tire cross-sectional height of the green tire T3 before tire vulcanization, it can be used.

[0026] [Modification Example] (A) In the above embodiment, an operator inputs information manually into the molding device 51, but it is not limited to this. For example, the production execution system 56, the calculation system 55, and the molding device 51 may be made communicable so that information is automatically transmitted to the molding device 51.

[0027] (B) The tire in the above embodiment is for a passenger car, but it is not limited to this. For example, it may be for a light truck (LT).

[0028] (C) The pneumatic tire of the first embodiment has a SWOT (SideWall On Tread) structure in which the sidewall rubber 9 lies on the tread rubber 8, but is not limited thereto. For example, it may have a TOS (Tread On Sidewall) structure in which the tread rubber 8 lies on the sidewall rubber 9.

[0029] [1] As described above, the method for manufacturing a pneumatic tire includes a step of winding a plurality of tire members including the carcass 4 around a carcass band drum 50 to generate a cylindrical first case body T1 having a pair of beads 1, a step of winding a plurality of tire members including the tread rubber 8 and the belt 6 around a belt drum 53 to generate a cylindrical second case body T2, a step of calculating a first distance L1, and a step of moving the pair of chucks 510 inward in the tire axial direction while inflating the first case body T1 from a first state in which the pair of beads 1 of the first case body T1 are respectively held by the pair of chucks 510 to a second state in which the distance between the pair of chucks 510 is shortened by the first distance L1, and integrating the first case body T1 and the second case body T2. The step of calculating the first distance L1 may be to calculate the first distance L1 based on the tire axial dimension L3 of the belt 6, the initial separation distance L0 along the tire axial direction AD of the pair of beads 1 in the first state, information regarding the rising height H1 along the tire radial direction RD from the inner end P2 of the bead 1 to the outer end P1 of the belt 6 in the second state, and the rising angle θ from the inner end P2 of the bead 1 to the outer end P1 of the belt 6 in the second state.

[0030] Since the first distance L1 (the approaching width) is calculated so that the rising angle θ becomes a specified angle, the rising angle θ becomes the specified angle regardless of the experience of the operator, and air entry can be suppressed.

[0031] [2] In the method for manufacturing a pneumatic tire according to [1] above, the information regarding the rising height H1 may include the diameter φ2 of the carcass band drum 50 and the diameter φ1 of the belt drum 53. Thus, based on the specifications of the tire after vulcanization (tire cross-sectional height) and the manufacturing conditions of the manufacturing apparatus adapted to the tire after vulcanization (the diameter φ2 of the carcass band drum 50 and the diameter φ1 of the belt drum 53), values can be calculated, so that the first distance L1 can be uniformly determined.

[0032] [3] The manufacturing system of the pneumatic tire according to the present embodiment includes a carcass band drum 50 around which a plurality of tire members including a carcass 4 are wound to generate a cylindrical first case body T1 having a pair of beads 1, a belt drum 53 around which a plurality of tire members including tread rubber 8 and a belt 6 are wound to generate a cylindrical second case body T2, a pair of chucks 510 capable of holding the pair of beads 1, and a calculation system 55 for calculating the first distance L1. From a first state in which the pair of beads 1 of the first case body T1 are respectively held by the pair of chucks 510, while inflating the first case body T1, the pair of chucks 510 are moved inward in the tire axial direction to make the distance between the pair of chucks 510 shorter by the first distance L1 to a second state, and the first case body T1 and the second case body T2 are configured to be integratable. The calculation system 55 is based on the tire axial dimension L3 of the belt 6, the initial separation distance L0 along the tire axial direction AD of the pair of beads 1 in the first state, information regarding the rising height H1 along the tire radial direction RD from the inner end P2 of the bead 1 to the outer end P1 of the belt 6 in the second state, and the rising angle θ from the inner end P2 of the bead 1 to the outer end P1 of the belt 6 in the second state, and may calculate the first distance L1.

[0033] As described above, the embodiments of the present disclosure have been described with reference to the drawings, but the specific configuration should be considered not to be limited to these embodiments. The scope of the present disclosure is shown not only by the description of the above-described embodiments but also by the claims, and further includes all modifications within the meaning and scope equivalent to the claims.

[0034] It is possible to adopt the structure employed in each of the above embodiments in any other embodiment. The specific configuration of each part is not limited to the above-described embodiments only, and various modifications are possible without departing from the spirit of the present disclosure.

[0035] For example, the execution order of each process such as operations, procedures, steps, and stages in the devices, systems, programs, and methods shown in the claims, the specification, and the drawings can be realized in any order as long as the output of the previous process is not used in the subsequent process. Regarding the flow in the claims, the specification, and the drawings, even if terms such as "first" and "next" are used for convenience of explanation, it does not mean that it is essential to execute in this order.

Description of Reference Numerals

[0036] 1: Bead 3: Tread 4: Carcass 6: Belt 8: Tread Rubber 50: Carcass Band Drum 53: Belt Drum 55: Calculation System 510: Chuck AD: Tire Axial Direction H1: Rise Height L0: Initial Separation Distance L1: First Distance L3: Tire Axial Dimension of Belt 6 RD: Tire Radial Direction T1: First Case Body T2: Second Case Body θ: Rise Angle φ1: Diameter of Belt Drum 53 φ2: Diameter of Carcass Band Drum 50

Claims

1. wrapping a plurality of tire members including a carcass around a carcass band drum to generate a cylindrical first case body having a pair of beads; wrapping a plurality of tire members including tread rubber and a belt around a belt drum to generate a cylindrical second case body; calculating a first distance; from a first state in which the pair of beads of the first case body are respectively held by a pair of chucks, while inflating the first case body, moving the pair of chucks inward in the tire axial direction to shorten the distance between the pair of chucks to the first distance, and integrating the first case body and the second case body; The step of calculating the first distance calculates the first distance based on the tire axial dimension of the belt, the initial separation distance along the tire axial direction of the pair of beads in the first state, information on the rising height along the tire radial direction from the inner end of the bead to the outer end of the belt in the second state, and the rising angle from the inner end of the bead to the outer end of the belt in the second state. A method for manufacturing a pneumatic tire.

2. The method for manufacturing a pneumatic tire according to claim 1, wherein the information on the rising height includes the diameter of the carcass band drum and the diameter of the belt drum.

3. a carcass band drum around which a plurality of tire members including a carcass are wrapped to generate a cylindrical first case body having a pair of beads; a belt drum around which a plurality of tire members including tread rubber and a belt are wrapped to generate a cylindrical second case body; a pair of chucks capable of holding the pair of beads; a calculation system for calculating a first distance; and configured to be able to integrate the first case body and the second case body by changing from a first state in which the pair of beads of the first case body are respectively held by the pair of chucks to a second state in which the distance between the pair of chucks is shortened to the first distance by moving the pair of chucks inward in the tire axial direction while inflating the first case body. The calculating system calculates the first distance based on the tire axial dimension of the belt, the initial separation distance along the tire axial direction of the pair of beads in the first state, information regarding the rising height along the tire radial direction from the inner end of the bead to the outer end of the belt in the second state, and the rising angle from the inner end of the bead to the outer end of the belt in the second state, in a manufacturing system for a pneumatic tire.

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