阅读说明：本技术 充气轮胎的制造方法 (Method for manufacturing pneumatic tire ) 是由 茂谷明宏 于 2020-02-17 设计创作，主要内容包括：本发明提供充气轮胎的制造方法,有助于提高轮胎的生产性以及品质,充气轮胎的制造方法包含如下工序：工序(A)测定将包含胎体帘布层在内的多个橡胶部件卷绕在第一鼓上而形成的第一成型体的厚度；工序(B)测定将包含胎面在内的其他多个橡胶部件卷绕在第二鼓上而形成的第二成型体的厚度；工序(C)将所述第一成型体和所述第二成型体组合而形成生胎；以及工序(D)按照根据所述第一成型体的厚度和所述第二成型体的厚度而决定的硫化时间对所述生胎进行硫化。(The present invention provides a method for manufacturing a pneumatic tire, which contributes to improvement of productivity and quality of the tire, the method for manufacturing the pneumatic tire comprising the steps of: measuring the thickness of a first molded body formed by winding a plurality of rubber members including a carcass ply around a first drum; measuring the thickness of a second molded body formed by winding a plurality of rubber members including a tread around a second drum; a step (C) of combining the first molded body and the second molded body to form a green tire; and (D) vulcanizing the green tire for a vulcanization time determined based on the thickness of the first molded body and the thickness of the second molded body.)

1. A method for manufacturing a tire, the method comprising the steps of:

measuring the thickness of a first molded body formed by winding a plurality of rubber members including a carcass ply around a first drum;

measuring the thickness of a second molded body formed by winding a plurality of rubber members including a tread around a second drum;

a step (C) of combining the first molded body and the second molded body to form a green tire; and

and (D) vulcanizing the green tire for a vulcanization time determined according to the thickness of the first molded body and the thickness of the second molded body.

2. The manufacturing method according to claim 1,

in the step (A), the thickness of the first molded body at a position corresponding to a position in the green tire where the temperature rise takes the most time is measured,

in the step (B), the thickness of the second molded article at a position corresponding to a position of the green tire where the temperature rise takes the most time is measured.

3. The manufacturing method according to claim 2,

in the step (A), the thickness of the first molded body is measured at predetermined circumferential intervals,

in the step (B), the thickness of the second molded article is measured at predetermined circumferential intervals,

in the step (C), the first molded body and the second molded body are combined at a relative position where a difference between a maximum value and a minimum value in a circumferential direction of a total thickness of the first molded body and the thickness of the second molded body is minimum.

4. The manufacturing method according to claim 3,

in the step (a) and the step (B), the circumferential interval is set at a center angle.

5. The manufacturing method according to claim 3 or 4,

in the step (B), the thickness of the second molded article is measured with the circumferential interval on the outer circumferential surface of the second drum set to 3mm or less.

6. The production method according to any one of claims 1 to 5,

in the step (D), the curing time is determined based on the thickness of the green tire based on a preset correlation between the thickness of the model of the green tire and the curing time.

7. The production method according to any one of claims 1 to 6,

in the step (a), the thickness of each of the plurality of rubber members after winding is measured every time the plurality of rubber members are wound around the first drum.

8. The production method according to any one of claims 1 to 7,

in the step (B), the thickness of each of the plurality of rubber members after winding is measured every time the plurality of rubber members are wound around the second drum.

Technical Field

The present invention relates to a method for manufacturing a pneumatic tire.

Background

Patent document 1 (japanese patent application laid-open No. 2014-19062) describes a technique of obtaining a tire from a green tire by vulcanizing the green tire. The following are described: in this vulcanization, it takes time for the thick wall portion such as the tread portion or the bead portion of the green tire to be heated. Therefore, the vulcanization time of the green tire is set so that heat is also sufficiently transmitted to the inside of such a thick-walled portion.

Patent document 1: japanese patent laid-open publication No. 2014-19062

Between the green tires, there is a variation in the time until completion of vulcanization. The vulcanization time of the green tire is set in consideration of the safety factor of the deviation. There are various causes of the variation in the time until completion of vulcanization, and the variation in the wall thickness is the cause thereof. Therefore, by measuring the thickness of the green tire, the vulcanization time of the green tire can be set with higher accuracy. By setting the vulcanization time with high accuracy, the extra time due to the safety factor can be shortened. In addition, the occurrence of overcuring due to an excessively long vulcanization time can be suppressed. By measuring the thickness of the vulcanized green tire in this way, productivity and quality of the tire can be improved.

However, the green tire has an annular shape, and the thickness of the green tire greatly varies depending on the location. It is not easy to measure the wall thickness. Further, the green tire is formed of unvulcanized rubber and is easily deformed. It is not easy to accurately measure the wall thickness of the green tire.

Disclosure of Invention

The purpose of the present invention is to provide a method for manufacturing a tire, which contributes to improvement in productivity and quality of the tire.

The method for manufacturing a pneumatic tire according to the present invention includes the steps of: measuring the thickness of a first molded body formed by winding a plurality of rubber members including a carcass ply around a first drum; measuring the thickness of a second molded body formed by winding a plurality of rubber members including a tread around a second drum; a step (C) of combining the first molded body and the second molded body to form a green tire; and (D) vulcanizing the green tire for a vulcanization time determined based on the thickness of the first molded body and the thickness of the second molded body.

Preferably, in the step (a), the thickness of the first molded body at a position corresponding to a position of the green tire where the temperature rise takes the most time is measured. In the step (B), the thickness of the second molded article at a position corresponding to a position of the green tire where the temperature rise takes the most time is measured.

Preferably, in the step (a), the thickness of the first molded body is measured at predetermined circumferential intervals. In the step (B), the thickness of the second molded article is measured at predetermined circumferential intervals. In the step (C), the first molded body and the second molded body are combined at a relative position where a difference between a maximum value and a minimum value in a circumferential direction of a total thickness of the first molded body and the thickness of the second molded body is minimum.

Preferably, in the step (a) and the step (B), the circumferential interval is set at a center angle.

Preferably, in the step (B), the thickness of the second molded article is measured with the circumferential interval on the outer circumferential surface of the second drum set to 3mm or less.

Preferably, in the step (D), the curing time is determined based on a thickness of the green tire based on a correlation between a thickness of a model of the green tire and the curing time, which is set in advance.

Preferably, in the step (a), the thickness of each of the plurality of rubber members after winding is measured every time the plurality of rubber members are wound around the first drum.

Preferably, in the step (B), the thickness of each of the plurality of rubber members after winding is measured every time the plurality of rubber members are wound around the second drum.

In the method of manufacturing a pneumatic tire of the present invention, the thickness is calculated for each green tire. And determining the vulcanization time of the green tire according to the calculated thickness. This suppresses the vulcanization time from becoming too long. In the manufacturing method, the thickness of a first molded body wound on a first drum is measured. The thickness of the second molded body wound on the second drum was measured. The thickness of the green tire is calculated from the thickness of the first molded body and the thickness of the second molded body. This makes it possible to calculate the thickness of the green tire easily and with high accuracy.

Drawings

Fig. 1 is a conceptual diagram illustrating a pneumatic tire molding apparatus according to an embodiment of the present invention.

Fig. 2 is an explanatory view showing a use state of the molding apparatus of fig. 1.

Fig. 3 is an explanatory view showing another use state of the molding apparatus of fig. 1.

Fig. 4 is an explanatory view showing still another use state of the molding apparatus of fig. 1.

Description of the reference symbols

2: a molding device; 4: a first molding device; 6: a second molding device; 8: a conveyance device; 10: a forming machine; 12: a first profilometry device; 14: a second profilometry device; 16: a control device; 18: a first drum; 18 a: an outer peripheral surface; 20: a second drum; 20 a: an outer peripheral surface; 28: a bead receiving section; 30: a first molded body; 32: a second molded body.

Detailed Description

The present invention will be described in detail below based on preferred embodiments with reference to the accompanying drawings as appropriate.

Fig. 1 shows a molding apparatus 2 used in the method of manufacturing a pneumatic tire of the present invention. The molding apparatus 2 includes a first molding device 4, a second molding device 6, a conveyor 8, a molding machine 10, a first profile measuring device 12, a second profile measuring device 14, and a control device 16.

The first forming device 4 has a first drum 18. The first drum 18 has a cylindrical shape. The first drum 18 is rotatable about its axis as a rotation axis. The first drum 18 can be expanded/reduced in diameter.

The second forming device 6 has a second drum 20. The second drum 20 has a cylindrical shape. The second drum 20 is rotatable about its axis as a rotation axis. The second drum 20 can be expanded/reduced in diameter.

The transport device 8 has a displacement device 22 and a holding device 24. The moving device 22 is movable between the second molding device 6 and the molding machine 10. The holding device 24 is mounted on the displacement device 22. The holder 24 has a ring frame 24a and a plurality of holders 24 b. Each holder 24b is disposed in the opening 24c of the ring frame 24 a. The holders 24b are arranged at equal intervals in the circumferential direction of the opening 24 c. The holder 24b is integrally rotatable about the axis of the ring frame 24a as a rotation axis.

The holder 24b has a body 24d and a clamp 24 e. The clamp 24e is supported on the main body 24 d. The jig 24e is movable in the radial direction of the opening 24 c. The plurality of jigs 24e can be expanded/reduced in diameter in the radial direction of the opening 24c while maintaining the same circumferential position in the cross section perpendicular to the axial direction.

The molding machine 10 has a pair of moving bodies 26 and a pair of bead receivers 28. Each moving body 26 has a cylindrical shape. The moving body 26 can move to a position close to and a position away from each other in the axial direction. The pair of bead receivers 28 are attached to the moving body 26. The axial distance between the pair of bead receivers 28 can be changed. The bead receiving portions 28 are movable to a position close to each other and a position away from each other in the axial direction. The pair of moving bodies 26 and the pair of bead receivers 28 are rotatable about their axes as rotation axes.

The first profilometer 12 has a body 12a and a sensor 12 b. The sensor 12b has a function of measuring the position of the outer peripheral surface of the object wound around the first drum 18, for example, a molded body wound around the first drum 18. The sensor 12b is not particularly limited, and is, for example, a laser sensor. The main body 12a has a function of transmitting the outer peripheral surface position data obtained from the sensor 12b to the control device 16.

The second profilometer 14 has a body 14a and a sensor 14 b. The sensor 14b has a function of measuring the position of the outer peripheral surface of the object wound around the second drum 20, for example, the molded body wound around the second drum 20. The sensor 14b is not particularly limited, and is, for example, a laser sensor. The main body 14a has a function of transmitting the outer peripheral surface position data obtained from the sensor 14b to the control device 16.

The control device 16 includes an arithmetic unit for performing arithmetic processing, a control unit for performing control processing of each device, a storage unit for storing data, an input unit for inputting information, an output unit for outputting information, and an interface unit for inputting a signal from the input device and outputting the signal to the output device. The control device 16 has a function of controlling the first molding device 4, the second molding device 6, the conveying device 8, the molding machine 10, the first profile measuring device 12, and the second profile measuring device 14. The control device 16 has, for example, a processor, a memory, a keyboard, a display, and an interface board.

The control device 16 has a function of receiving the outer peripheral surface position data from the first contour measuring device 12. The control device 16 has a function of storing the outer peripheral surface position data and circumferential position data of the first drum 18 corresponding to the outer peripheral surface position data. The control device 16 has a function of calculating the thickness of the molded body wound on the first drum 18 from the outer peripheral surface position data. The control device 16 has a function of receiving the outer peripheral surface position data from the second profile measuring device 14. The control device 16 has a function of storing the outer peripheral surface position data and the circumferential position data of the second drum 20 corresponding to the outer peripheral surface position data. The control device 16 has a function of calculating the thickness of the molded body wound on the second drum 20 from the outer peripheral surface position data.

Fig. 2 shows a state of use of the first molding device 4. Fig. 2 shows the first drum 18 of the first forming device 4 and the first formed body 30 wound on the first drum 18. The first molded body 30 has an inner liner member 30a, a carcass ply 30b, a pair of bead members 30c, and a sidewall member 30 d.

The inner liner member 30a is a member forming an inner liner of a tire. The carcass ply 30b is a component forming the carcass of the tire. The pair of bead components 30c are components that form the beads of the tire. The sidewall component 30d is a component that forms a sidewall of the tire. In fig. 2, an inner liner component 30a, a carcass ply 30b, and a sidewall component 30d, each in a belt shape, are wound around the first drum 18 and superposed. These members are combined with an annular bead member. These members are wound around the outer peripheral surface 18a to form a first molded body 30.

The one-dot chain line L1 of fig. 2 indicates the rotational axis of the first drum 18. The one-dot chain line Ps1 in fig. 2 indicates the measurement position in the axial direction of the sensor 12b of the first profile measuring apparatus 12.

Fig. 3 shows a state of use of the second molding device 6. Fig. 3 shows the second drum 20 of the second molding device 6 and the second molded body 32 wound on the second drum 20. The second molded body 32 has a first belt member 32a, a second belt member 32b, and a tread member 32 c.

The first belt member 32a is a member forming a first belt of the tire. The second belt member 32b is a member forming a second belt of the tire. The tread member 32c is a member forming the tread of the tire. In fig. 3, a first belt member 32a, a second belt member 32b, and a tread member 32c, each in a belt shape, are wound around the second drum 20 and are superposed. They are wound around the outer peripheral surface 20a to form a second molded body 32.

The one-dot chain line L2 of fig. 3 indicates the rotational axis of the second drum 20. The one-dot chain line Ps2 in fig. 3 indicates the measurement position in the axial direction of the sensor 14b of the second profile measuring apparatus 14.

Fig. 4 shows a state of use of the molding machine 10. Fig. 4 shows the bead support 28 of the molding machine 10, a part of the holding device 24 of the transport device 8, the first molded body 30 and the second molded body 32. The first molded body 30 and the second molded body 32 are combined to obtain a green tire. The green tire has a toroidal shape. The pair of bead receiving portions 28 are disposed close to each other in the axial direction. The retainer 24b of the retainer 24 is located radially outward of the pair of bead receivers 28.

In fig. 4, a part of a first molded body 30 having a cylindrical shape and a pair of bead receiving portions 28 supporting the first molded body 30 are shown by two-dot chain lines. The pair of bead receiving portions 28 are provided apart from each other in the axial direction.

The one-dot chain line Ps in fig. 4 indicates the axial position of the green tire where the temperature rise most takes time. The axial position Ps corresponds to the latitude when the axial center of the green tire is set as the equatorial plane. In this green tire, the position Ps is the thickest position. The position Ps1 of the first molded body 30 of fig. 2 indicates a position in the first molded body 30 at the position Ps of the green tire when the green tire is formed. In the present invention, this position Ps1 of the first molded body 30 corresponds to this position Ps. Similarly, a position Ps2 of the second molded body 32 of fig. 3 corresponds to this position Ps.

In this green tire, the position Ps that requires the most time for temperature rise will be described by taking the axial center of the tread as an example, but the present invention is not limited thereto. The position Ps where the temperature rise takes the most time differs depending on the shape of the green tire and the like. For example, depending on the green tire, the position of the sidewall shown by the one-dot chain line Ps' in fig. 4 or the position near the bead shown by the one-dot chain line Ps ″ may be used. For the green tire that requires the most time for temperature rise at this position Ps ', the respective thicknesses are measured at the position in the first molded body 30 and the position in the second molded body 32 corresponding to this position Ps'. In addition, for the green tire that most requires time for temperature rise at the position Ps ", the respective thicknesses are measured at the position in the first molded body 30 and the position in the second molded body 32 corresponding to the position Ps".

A method of manufacturing a tire using the molding apparatus 2 will be described with reference to fig. 1 to 4. The method for manufacturing the tire includes a molding step and a vulcanization step. In the molding step, the components forming each part of the tire are combined to form a green tire using the molding apparatus 2. In the vulcanization step, the green tire is vulcanized. By this vulcanization, a tire is obtained from the green tire.

In this molding process, a plurality of members for forming the first molded body 30, such as the inner liner member 30a, the carcass ply 30b, the pair of bead members 30c, and the pair of sidewall members 30d, are prepared (step 1).

The plurality of components prepared in step 1 are sequentially wound on the first drum 18 (step 2). In step 2, first, the inner liner member 30a is wound around the outer circumferential surface 18a of the first drum 18. While the inner liner member 30a is wound, the position of the outer peripheral surface of the inner liner member 30a is measured at a position Ps 1. The thickness of the liner member 30a is measured from the difference in the radial direction between the position of the outer peripheral surface of the liner member 30a and the position of the outer peripheral surface 18a of the first drum 18. At this position Ps1, the thickness of the inner liner member 30a is measured at a predetermined circumferential interval of the first drum 18, for example, at an interval having a center angle of 3 °. The control device 16 stores the measured thickness and the measured position in the circumferential direction. The measured circumferential position can be easily grasped from the rotational position of the first drum 18.

Next, the carcass ply 30b is wound around the outer peripheral surface of the inner liner member 30 a. The position of the outer peripheral surface of the carcass ply 30b is measured at a position Ps1 while the carcass ply 30b is wound. The thickness of the carcass ply 30b is measured. The control device 16 stores the measured positions of the thickness and the circumferential direction. A bead member 30c is disposed on the outer peripheral surface of the wound carcass ply 30 b. The ends of the carcass ply 30b are folded back around the bead members 30 c. Further, a pair of sidewall members 30d are wound around the outer peripheral surface of the carcass ply 30 b. Thus, the plurality of components prepared in step 1 are sequentially wound on the first drum 18, as shown in fig. 2, to form a first molded body 30. In this step 2, at the position Ps1, the thickness of the intermediate body around which each component is wound and the thickness of the first molded body 30 are obtained together with the measured circumferential position.

Other plural members forming the second molded body 32, such as the first belt member 32a, the second belt member 32b, the tread member 32c, and the like, are prepared (step 3).

The other plural components prepared in step 3 are sequentially wound on the second drum 20 (step 4). In step 4, first, the first belt member 32a is wound around the outer peripheral surface 20a of the second drum 20. While the first belt member 32a is wound, the position of the outer peripheral surface of the first belt member 32a is measured at the position Ps 2. The thickness of the first belt member 32a is measured from the difference in the radial direction between the position of the outer peripheral surface of the first belt member 32a and the position of the outer peripheral surface 20a of the second drum 20. At this position Ps2, the thickness of the first belt member 32a is measured at predetermined circumferential intervals, for example, at intervals having a center angle of 3 °, in the circumferential direction of the second drum 20, as in step 2. The control device 16 stores the measured positions of the thickness and the circumferential direction.

Next, the second belt member 32b is wound around the outer peripheral surface of the first belt member 32 a. While winding the second belt member 32b, the position of the outer peripheral surface of the second belt member 32b is measured at the position Ps 2. The thickness of the second belt member 32b was measured. The control device 16 stores the measured positions of the thickness and the circumferential direction. The tread member 32c is wound around the outer peripheral surface of the second belt member 32 b. While the tread member 32c is wound, the position of the outer peripheral surface of the tread member 32c is measured at the position Ps 2. The thickness of the tread element 32c is measured. The control device 16 stores the measured positions of the thickness and the circumferential direction. Thus, the other plural members prepared in step 3 are sequentially wound on the second drum 20, and as shown in fig. 3, a second molded body 32 is formed. In this step 4, at the position Ps2, the thickness of the intermediate body around which each part is wound and the thickness of the second molded body 32 are obtained together with the measured circumferential position.

The first molded body 30 obtained in step 2 is placed on the molding machine 10 (step 5). As shown by the two-dot chain line in fig. 4, the end portion of the first molded body 30 is supported by the bead receiving portion 28.

The second molded article 32 obtained in step 4 is arranged radially outward of the first molded article 30 (step 6). In step 6, the second molded article 32 held by the holder 24b of the conveying device 8 shown in fig. 1 is arranged radially outward of the first molded article 30. The control device 16 stores the thickness and the circumferential position of the first molded body 30 at the position Ps1, and the thickness and the circumferential position of the second molded body 32 at the position Ps 2. The relative positions at which the first molded body 30 and the second molded body 32 are joined in such a manner as to uniformize the thickness at the position Ps in the circumferential direction are calculated. Specifically, the relative positions at which the first molded body 30 and the second molded body 32 are joined so that the difference between the maximum value and the minimum value of the thickness at the position Ps is minimized are calculated. Both or either one of the first molded body 30 and the second molded body 32 is rotated so that the first molded body 30 and the second molded body 32 are in the relative position.

The first molded body 30 is filled with a pressure fluid (e.g., air) to expand the first molded body 30 in a circular ring shape (step 7). In step 7, the pair of bead receiving portions 28 move in a direction to approach each other as the first molded body 30 expands. As shown in fig. 4, the outer peripheral surface of the expanded first molded body 30 is bonded to the inner peripheral surface of the second molded body 32 (step 8). Then, the second molded body 32 is pressed against the first molded body 30 by a stitching machine (stitcher), not shown (step 9). Thus, a green tire is formed.

The control device 16 calculates the thickness of the green tire at the position Ps (step 10). In this step 10, the control device 16 calculates the thickness of the green tire at the position Ps from the thickness of the first molded body 30 at the position Ps1 and the thickness of the second molded body 32 at the position Ps 2.

The control device 16 determines the vulcanization time based on the thickness of the green tire at the position Ps (step 11). For example, a correlation between the thickness at the position Ps and the vulcanization time is obtained in advance using a model of the green tire. The control device 16 stores the correlation. The thickness calculated in step 10 is regarded as the thickness in the correlation, and the vulcanization time is determined.

In the vulcanization step, the green tire is vulcanized for the vulcanization time determined in step 11 (step 12). By this vulcanization, a tire is obtained from the green tire.

In this method of manufacturing a tire, in step 10, the thickness is calculated for each green tire. In step 11, the curing time of the green tire is determined based on the calculated thickness. Thereby, the vulcanization time is suppressed from becoming excessively long. In addition, in the tire obtained from the green tire, over-vulcanization or under-vulcanization is suppressed.

In step 2, the thickness of the first molded body 30 wound on the first drum 18 is measured. Since the first molded body 30 is wound around the first drum 18, deformation is suppressed. Since the measurement is performed with reference to the outer peripheral surface 18a of the first drum 18, the thickness can be measured with high accuracy. In step 4, the thickness of the second molded body 32 wound on the second drum 20 is measured. Thus, the thickness of the second molded body 32 can be measured with high accuracy, as in the case of the first molded body 30.

The thickness of the green tire at the position Ps where the temperature rise most takes time is calculated. In the first molded body 30, the thickness is measured at a position Ps1 corresponding to the position Ps. In the second molded body 32, the thickness is measured at a position Ps2 corresponding to the position Ps. Thus, in the tire manufacturing method, the green tire can be vulcanized for a more appropriate vulcanization time.

The position Ps where the temperature of the green tire increases in the axial direction for the most time is not limited to the tread center as in the green tire. The position Ps where the temperature rise takes the most time differs depending on the shape of the green tire and the like. For example, as shown in fig. 4, it may take the most time to heat up at the position Ps' of the periphery of the sidewall or the position Ps ″ of the periphery of the bead. In such a green tire, the thicknesses of the first molded body 30 and the second molded body 32 are measured at positions corresponding to the position Ps' or the position Ps ″.

In this green tire, the measurement of the thickness at the position Ps1 and the measurement of the thickness at the position Ps2 are performed in the radial direction, but not limited thereto. As described above, the thicknesses of the first molded body 30 and the second molded body 32 at the positions corresponding to the positions Ps' of the periphery of the sidewall of the green tire are measured in the directions inclined in the radial direction corresponding to the thickness direction measured in the green tire. Even with respect to the thicknesses of the first molded body 30 and the second molded body 32 at positions corresponding to the position Ps ″ of the periphery of the bead of the green tire, the measurement is performed in a direction inclined in the radial direction corresponding to the thickness direction measured in the green tire.

In this step 2, the thickness of the first molded body 30 is measured at intervals of 3 ° in the circumferential direction of the first drum 18 at the center angle. This makes it possible to grasp the relationship between the measurement position in the circumferential direction of the first molded body 30 and the thickness at that position. In step 4, the thickness of the second molded body 32 is measured at intervals of 3 ° in the circumferential direction of the second drum 20. This makes it possible to grasp the relationship between the measurement position of the second molded body 32 in the circumferential direction and the thickness at that position. In step 6, the first molded body 30 and the second molded body 32 are arranged at circumferentially opposite positions so that the total thickness of the first molded body 30 and the second molded body 32 is uniform in the circumferential direction. This makes the thickness of the resulting green tire uniform in the circumferential direction at the position Ps.

In this step 2, the thickness of the first molded body 30 is measured at intervals of 3 ° in the circumferential direction of the first drum 18 at the center angle. In step 4, the thickness of the second molded body 32 is measured at intervals of 3 ° in the circumferential direction of the second drum 20. In this manufacturing method, the circumferential interval is set in accordance with the center angle. This enables the thickness to be measured at intervals in the circumferential direction corresponding to the first molded body 30 and the second molded body 32 having different diameters. In the present invention, measurement may be performed at other circumferential intervals such as a circumferential distance in both or either of step 2 and step 4.

In step 4, the thickness of the second molded article 32 is measured at predetermined circumferential intervals. By reducing this circumferential interval, measurement can be performed with high accuracy. In addition, the thickness of the joint portion at the circumferential end of the member that is not wound from the measurement object can be suppressed. The joint portion is the thickest portion, and is preferably grasped from the viewpoint of calculating the thickness of the green tire. From the viewpoint of suppressing the measurement omission of the thickness of the joint portion, the circumferential interval of the second molded member 32 is preferably 3mm or less in the circumferential direction of the inner circumferential surface of the second molded member 32. From this viewpoint, the circumferential interval is preferably 3mm or less in the circumferential direction of the outer peripheral surface 20a of the second drum 20 around which the second molded member 32 is wound. In addition, since the radius of the first molded body 30 is smaller than that of the second molded body 32, the circumferential interval of the first molded body 30 in step 2 may be determined so as to correspond to the circumferential interval of the second molded body 32.

In step 11, a correlation between the thickness and the vulcanization time is obtained in advance using a model of the green tire. The vulcanization time is determined based on the correlation and the calculated thickness at the position Ps. This makes it possible to easily and appropriately vulcanize the green tire.

In step 2, the thickness of the inner liner member 30a is measured. The thickness of the carcass ply 30b wound around the inner liner member 30a is measured. In step 2, the thickness of each of the plurality of tape-like members is measured every time the tape-like members are wound. Thus, when the thickness of the first molded body 30 varies, it is possible to easily grasp which member causes the variation in thickness.

In step 4, the thickness of the first belt member 32a is measured. The thickness of the second belt member 32b wound around the first belt member 32a was measured. The thickness of the tread member 32c wound around the second belt member 32b was measured. In step 4, the thickness of each of the other plurality of strip-shaped members is measured every time the strip-shaped members are wound. Thus, when the thickness of the second molded body 32 varies, it can be easily grasped which member causes the variation in thickness.

In the method for manufacturing a tire of the present invention, in step 10, it is not necessarily required to calculate the thickness of the green tire. As long as the thickness of the green tire at the position Ps can be grasped. Therefore, in step 11, the vulcanization time may also be determined according to the thickness of the first molded body 30 at the position Ps1 and the thickness of the second molded body 32 at the position Ps 2.