Method and system for manufacturing a tire

Abstract

To provide a method and a system for manufacturing a tire capable of manufacturing the tire excellent in quality with good productivity by suppressing winding collapse of a strip material of unvulcanized rubber wound around a drum body.SOLUTION: For each of rubber specifications of a strip material S, each proper range of an extension condition and surface temperature of the strip material S when winding it around a drum body 2 is grasped in advance, and a speed ratio between a winding speed of the strip material S around the drum body 2 and a conveying speed of the strip material S conveyed toward the drum body 2 is controlled by a control device 8. The surface temperature of the strip material S immediately before the strip material S is wound around the outer peripheral side of the drum body 2 is set within the proper range by controlling the temperature control device 6 based on the comparison between the surface temperature of the strip material S conveyed toward the drum body 2 detected by the temperature sensors 5 and the proper range of the surface temperature grasped in advance.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a tire manufacturing method and system, and more particularly to a tire manufacturing method and system that can produce high-quality tires with high productivity by suppressing the collapse of unvulcanized rubber strip material wound around a drum body during the tire building process. [Background technology]

[0002] A method for forming a green tire by spirally winding a strip of unvulcanized rubber around a forming drum is known (see, for example, Patent Document 1). In the invention proposed in Patent Document 1, the withdrawal speed of the strip material is made faster than the extrusion speed to apply a predetermined tension to the strip material, and the withdrawal speed and the drum winding speed are made the same to wind the strip material around the forming drum (paragraphs 0014-0015 of Patent Document 1). This reduces the amount of shrinkage of the strip material after it has been wound around the forming drum, allowing for a stable production of a rubber member with the desired shape.

[0003] However, because the tensile properties of the strip material vary depending on the rubber specifications, it is difficult to accurately apply the desired tension even by controlling the extrusion and withdrawal speeds of the strip material. As a result, it is not possible to sufficiently prevent the strip material from unwinding on the building drum. Furthermore, because the strip material has a smaller cross-sectional area than the typical unvulcanized rubber extrusions used as tread rubber and sidewall rubber, the rubber temperature (surface temperature) is likely to decrease along the transport path from the extruder to the building drum. As the surface temperature decreases, the adhesive strength of the strip material decreases, making it more likely to unwind. Therefore, there is room for improvement in preventing the unwinding of the unvulcanized rubber strip material wound around the building drum. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Laid-Open No. 2009-143165 Summary of the Invention [Problem to be solved by the invention]

[0005] An object of the present invention is to provide a tire manufacturing method and system that can suppress collapse of the unvulcanized rubber strip material wound around a drum body during the tire building process, thereby producing high-quality tires with high productivity. [Means for solving the problem]

[0006] In order to achieve the above object, the tire manufacturing method of the present invention involves spirally winding a strip of unvulcanized rubber around the outer periphery of a drum body to form a green tire, and then vulcanizing this green tire.The tire manufacturing method is characterized in that, for each rubber specification of the strip material, the appropriate ranges for the degree of elongation and surface temperature of the strip material when it is wound are determined in advance, and the strip material is wound around the outer periphery of the drum body with the degree of elongation and surface temperature within the appropriate ranges just before it is wound around the outer periphery of the drum body.

[0007] The tire manufacturing system of the present invention has an extruder that extrudes unvulcanized rubber strip material, a drum body around which the strip material is spirally wound, and a vulcanizing device that vulcanizes a green tire having tire components formed from the spirally wound strip material, and is characterized in that it also has a control device to which the appropriate ranges for the degree of elongation and surface temperature of the strip material when it is wound around the drum body, which are determined in advance for each rubber specification of the strip material, are input, a temperature sensor that detects the surface temperature of the strip material as it is transported towards the drum body, and a temperature adjustment device, wherein the control device controls the speed ratio between the winding speed of the strip material around the drum body and the conveying speed of the strip material as it is transported towards the drum body, so that the degree of elongation of the strip material just before it is wound around the outer periphery of the drum body is within the appropriate range, and the temperature adjustment device is controlled based on a comparison between the temperature detected by the temperature sensor and the predetermined appropriate range of the surface temperature, so that the surface temperature of the strip material just before it is wound around the outer periphery of the drum body is within the appropriate range. [Effects of the Invention]

[0008] According to the present invention, the degree of elongation and surface temperature of the strip material immediately before being wound around the outer periphery of the drum are each set within appropriate ranges determined in advance for each rubber specification of the strip material. This allows the strip material to be wound around the drum with an appropriate winding force and with appropriate adhesiveness. Therefore, the strip material is wound securely and stably around the drum, preventing it from becoming unwound. This is advantageous for the production of high-quality tires with high productivity. [Brief explanation of the drawings]

[0009] [Figure 1] 1 is an explanatory diagram illustrating a side view of a molding process in an embodiment of a tire manufacturing system. [Figure 2] 2 is an explanatory diagram illustrating, in cross section, the upper half of a drum body around which a strip material is wound, along with the winding roller and the pressure roller of FIG. 1; FIG. [Figure 3] FIG. 2 is a graph illustrating the relationship between tensile stress and strain of unvulcanized rubber forming the strip material. [Figure 4] FIG. 2 is a graph illustrating the relationship between the temperature and adhesive strength of unvulcanized rubber forming the strip material. [Figure 5] FIG. 10 is a graph illustrating an example of an appropriate range of temperature and elongation of a strip material. [Figure 6] 3 is an explanatory diagram illustrating a schematic example of the arrangement of a strip material wound around the drum body of FIG. 2.

[0023] FIG. [Figure 7] 3 is an explanatory diagram illustrating a state in which the strip material wound around the drum body of FIG. 2 is pressed by a pressure roller. FIG. [Figure 8] 8 is an explanatory view illustrating a green tire molded on the outer peripheral surface of the drum body of FIG. 7.

[0023] FIG. DETAILED DESCRIPTION OF THE INVENTION

[0010] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A tire manufacturing method and system according to the present invention will be described below based on the embodiments shown in the drawings.

[0011] In the molding process illustrated in Fig. 1, a green tire G is molded. The molded green tire G is vulcanized in a vulcanization process by a vulcanization device to manufacture a tire T. Therefore, the embodiment of the tire manufacturing system includes molding equipment used in the molding process illustrated in Fig. 1 and a vulcanization device used in the vulcanization process. Various known types of vulcanization devices can be used, so a description thereof will be omitted.

[0012] The molding equipment illustrated in Fig. 1 includes an extruder 1, a drum body 2, a temperature sensor 5, a temperature regulator 6, and a control device 8. The temperature sensor 5 and the temperature regulator 6 are disposed between the extruder 1 and the drum body 2. A plurality of support rollers 7a, 7b, and 7c are disposed between the extruder 1 and the temperature sensor 5. A winding roller 3 and a pressure roller 4 are disposed near the outer circumferential surface of the drum 2.

[0013] An extruder 1 extrudes a strip material S of unvulcanized rubber. This strip material S is transported toward a drum body 2. Various known types of extruder 1 can be used. The strip material S is extruded in a cross-sectional shape that corresponds to the shape of the extrusion outlet of a die attached to the head of the extruder 1. The cross-sectional shape of the strip material S can be a variety of shapes, including a simple circle, an ellipse, a trapezoid, a triangle, and a rectangle. The cross-sectional area of ​​the strip material S is, for example, 25 mm 2 Over 70mm 2 In this embodiment, the cross-sectional shape of the strip material S is a wide flat shape (approximately rectangular). The thickness / width dimension of the flat strip material S is, for example, 0.03 or more and 0.5 or less.

[0014] The extruded strip material S is stretched over support rollers 7a, 7b, and 7c arranged in front of the extruder 1. In this embodiment, three support rollers 7a, 7b, and 7c are arranged, but the number is not particularly limited and can be any appropriate number. In this embodiment, the support roller 7a arranged in the forefront position (forefront in the conveying direction) is a drive roller, and the other support rollers 7b and 7c are free rollers. The rotation of the support roller 7a is controlled by a control device 8. The rotational speed of the support roller 7a (the circumferential speed of the outer peripheral surface of the roller) is the conveying speed Vf of the strip material S being conveyed toward the drum body 2.

[0015] The cylindrical drum body 2 is supported by a support shaft 2a that passes through the cylindrical axis and extends in the width direction of the drum body 2. The drum body 2 rotates around the support shaft 2a. The strip material S transported from the extruder 1 toward the drum body 2 is sandwiched between the winding roller 3 and the outer peripheral surface of the drum body 2 and wound around the outer periphery of the drum body 2.

[0016] Therefore, the section from the tip of the extruder 1 to the winding roller 3 forms the transport path for the strip material S. In the section from the tip of the extruder 1 to the support roller 7a, which is located at the forefront, the strip material S is supported in a hanging state between the support rollers 7a, 7b, and 7c. These support rollers 7a, 7b, and 7c function as a festoon device for the strip material S.

[0017] In the conveying path of the strip material S, the section from the support roller 7a to the winding roller 3 is the section immediately before winding. In this section immediately before winding, a temperature sensor 5 and a temperature adjustment device 6 are arranged, in that order. In this embodiment, the strip material S is wound around the outer peripheral surface of the tire component M that is already placed on the outer peripheral surface of the drum body 2, but it may also be wound directly around the outer peripheral surface of the drum body 2. In other words, the strip material S is wound around the outer peripheral surface of the drum body 2 directly or indirectly via the tire component M, and therefore, in this specification, it is described that the strip material S is wound around the outer peripheral side of the drum body 2.

[0018] The strip material S is wound spirally around the outer periphery of the drum body 2. Therefore, the support roller 7a, winding roller 3, and pressure roller 4 move in the width direction of the drum body 2 relative to the drum body 2, which is fixed in a predetermined position and rotates around the support shaft 2a. These width direction movements and the rotation of the drum body 2 are controlled by a control device 8. If necessary, the temperature sensor 5 and temperature adjustment device 6 also move in the width direction of the drum body 2. Alternatively, the support roller 7a, winding roller 3, and pressure roller 4 can be fixed in predetermined positions, and the drum body 2 can move in the width direction of the drum body 2 while rotating around the support shaft 2a.

[0019] As shown in FIG. 2, in this embodiment, a rigid core is used as the drum body 2. The rigid core has an outer surface that corresponds to the inner surface of a vulcanized tire manufactured by vulcanizing a green tire G. A tire component M has already been formed on the outer peripheral surface of this drum body 2. This tire component M is formed by a known method using an inner liner, a carcass material, a pair of beads, side rubber, a belt material, etc., and is in a state where only tread rubber is missing. Therefore, in this embodiment, a strip material S is spirally wound around the outer peripheral surface of this tire component M as tread rubber. The drum body 2 is not limited to a rigid core, and a building drum commonly used in tire building can also be used.

[0020] As shown in Fig. 2, the rotation axes and outer peripheral surfaces of the winding roller 3 and the pressure roller 4 are inclined relative to the support shaft 2a, but this angle of inclination is changeable. In Fig. 2, the rotation axes of the winding roller 3 and the pressure roller 4 are indicated by dashed lines, with the upper dashed line being the rotation axis of the winding roller 3 and the lower dashed line being the rotation axis of the pressure roller 4.

[0021] The winding roller 3 is a drive roller that rotates around its rotation axis, and its rotation is controlled by a control device 8. The rotational speed of the winding roller 3 (the circumferential speed of the roller's outer peripheral surface) is the winding speed Vd of the strip material S onto the drum body 2. The circumferential speed of the outer peripheral surface of the drum body 2 at the position where the outer peripheral surface of the winding roller 3 faces it is substantially the same as this winding speed Vd. Strictly speaking, when the strip material S is wound onto the outer peripheral surface of the tire component M that is already placed on the outer peripheral surface of the drum body 2, the circumferential speed of the outer peripheral surface of the tire component M at the position where the outer peripheral surface of the winding roller 3 faces it is substantially the same as this winding speed Vd. When the strip material S is wound directly onto the outer peripheral surface of the drum body 2, the circumferential speed of the outer peripheral surface of the drum body 2 at the position where the outer peripheral surface of the winding roller 3 faces it is substantially the same as this winding speed Vd.

[0022] The pressure roller 4 rolls on the surface of the strip material S immediately after it has been wound around the outer periphery of the drum body 2 by the winding roller 3, thereby pressing the strip material S. The pressure roller 4 is a free roller that rotates around its own rotation axis.

[0023] The temperature sensor 5 detects the surface temperature of the strip material S being transported toward the drum 2. Various known non-contact temperature sensors can be used as the temperature sensor 5. It is desirable to detect the surface temperature of the strip material S at a position on the transport path as close to the drum 2 as possible. Therefore, as in this embodiment, it is advisable to detect the surface temperature of the strip material S using the temperature sensor 5 in the section just before winding. In this embodiment, the temperature of the surface of the strip material S that is wound opposite the outer peripheral surface of the drum 2 (the inner peripheral surface) is detected. The surface temperature of the strip material S detected by the temperature sensor 5 is input to the control device 8.

[0024] The temperature adjusting device 6 is disposed at a position closer to the drum body 2 than the temperature sensor 5 with respect to the transport path of the strip material S, and adjusts (changes) the surface temperature of the strip material S in the section immediately before winding. To raise the surface temperature of the strip material S, for example, a heating roller heated to a predetermined temperature or a hot air blower is used. To lower the surface temperature of the strip material S, for example, a cooling roller cooled to a predetermined temperature or a cold air blower is used. The temperature of the strip material S immediately after extrusion is, for example, about 90°C to 120°C, but it is naturally cooled while being transported along the transport path. For this reason, a temperature adjusting device 6 that raises the surface temperature of the strip material S is usually used.

[0025] The control device 8 controls the operation of various components of this molding equipment. Various known computers are used as the control device 8. For each rubber specification of the strip material S, an appropriate range Ae of the elongation degree and an appropriate range At of the surface temperature when the strip material S is wound around the drum body 2 are determined in advance. These predetermined appropriate ranges Ae and At are then input to the control device 8.

[0026] The appropriate ranges Ae and At will now be described. First, the appropriate range Ae will be described.

[0027] The degree of stretching of the strip material S when it is wound around the drum body 2 affects the degree of shrinkage of the strip material S wound around the drum body 2. If this degree of shrinkage is large, the strip material S will be tightly and stably wound around the drum body 2 (the tire component M on the outer peripheral surface of the drum body 2), and if this degree of shrinkage is small, the strip material S will be wound in an unstable state. However, if the degree of stretching of the strip material S is excessive, the strip material S will break. Therefore, the degree of stretching of the strip material S just before it is wound around the outer peripheral surface of the drum body 2 must be set within the appropriate range Ae.

[0028] The relationship between tensile stress and strain of the unvulcanized rubber forming the strip material S shown in Figure 3 varies depending on the rubber specifications, and even if the rubber specifications are the same, it varies depending on the rubber temperature. In Figure 3, for unvulcanized rubber with the same rubber specifications, the solid line Ta indicates a high rubber temperature, the thick dashed line Tb indicates a medium rubber temperature, and the thin dashed line Tc indicates a low rubber temperature. The magnitude of this tensile stress and strain is proportional to the winding force of the strip material S.

[0029] For the same rubber specifications, the lower limit Fn and upper limit Fx of the appropriate tensile stress (winding force) when winding the strip material S around the drum body 2 are the same regardless of the rubber temperature, and these lower limit Fn and upper limit Fx can be determined by prior testing, etc. Therefore, the appropriate range of strain when winding the strip material S around the drum body 2 differs for each rubber specification and depending on the rubber temperature.

[0030] This strain can be treated as the degree of elongation of the strip material S, and therefore the appropriate range of this strain can be understood as the appropriate range Ae of the degree of elongation of the strip material S. The degree of elongation of the strip material S depends on the magnitude of the difference between the above-mentioned conveying speed Vf and the winding speed Vd. Therefore, in this embodiment, as will be described later, the degree of elongation of the strip material S is set to the appropriate range Ae of the degree of elongation when winding the strip material S around the drum body 2 by controlling the speed ratio Vd / Vf.

[0031] Next, the appropriate range At will be described.

[0032] The surface temperature of the strip material S when it is wound around the drum body 2 affects the degree of adhesion of the strip material S wound around the drum body 2 to the outer peripheral surface of the drum body 2 (the outer peripheral surface of the tire component M arranged on the outer peripheral surface of the drum body 2a). If this adhesion is strong, the strip material S will be tightly and stably wound around the drum body 2 (the tire component M arranged on the outer peripheral surface of the drum body 2a), and if this adhesion is weak, the strip material S will be unstably wound. However, if the surface temperature of the strip material S is excessively high, the strip material S will unnecessarily adhere to adjacent components and equipment on the transport path, hindering smooth transport. Therefore, the surface temperature of the strip material S immediately before it is wound around the outer peripheral surface of the drum body 2 must be set within the appropriate range At.

[0033] As shown in Figure 4, the relationship between the adhesive strength of the unvulcanized rubber forming the strip material S and the rubber temperature generally increases as the rubber temperature increases. Figure 4 shows the relationship between adhesive strength and rubber temperature for unvulcanized rubbers Sa and Sb with different rubber specifications. Different rubber specifications result in different changes in adhesive strength with rubber temperature (data slope). This adhesive strength is proportional to the adhesion of the strip material S. The lower limit Hn and upper limit Hx of adhesive strength appropriate for winding the strip material S around the drum 2 are the same regardless of the rubber specifications, and these lower limit Hn and upper limit Hx can be determined through advance testing, etc. Therefore, the appropriate range At of the rubber temperature (surface temperature) when winding the strip material S around the drum 2 differs depending on the rubber specifications.

[0034] Therefore, taking into consideration the data in Figures 3 and 4, preliminary tests are conducted, and based on the test results, the appropriate range Ae of the degree of elongation and the appropriate range At of the surface temperature when the strip material S is wound around the drum body 2, as shown in Figure 5, are determined and set for each rubber specification of the unvulcanized rubber that forms the strip material S. The area surrounded by the thick line in Figure 5 indicates the appropriate range that satisfies both the appropriate range Ae and the appropriate range At.

[0035] An example of a procedure for molding the green tire G using the molding equipment of FIG. 1 will be described below.

[0036] A strip material S is wound spirally around the outer periphery of the drum body 2 shown in FIG. 2. A tire component M has already been formed on this drum body 2, and the strip material S is wound around the outer periphery of this tire component M. As shown in FIG. 6, the strip material S is wound spirally so as to overlap slightly in the width direction of the drum body 2. Therefore, in a cross-sectional view of the drum body 2, the outer periphery of the wound strip material S is slightly inclined with respect to the outer periphery of the tire component M (drum body 2). The inclination angle of the strip material S is known in advance. In addition, the cross-sectional shape (profile) of the outer periphery of the tire component M (drum body 2) is known in advance.

[0037] Therefore, when winding the strip material S in a spiral shape, the control device 8 controls the winding roller 3 and the pressure roller 4 to change the inclination angle of the central axis (outer peripheral surface) based on this profile, which is known in advance, and the inclination angle of the strip material S relative to this profile. As a result, the outer peripheral surfaces of the winding roller 3 and the pressure roller 4 become substantially parallel to the outer peripheral surface of the strip material S wound around the outer peripheral surface of the tire component M.

[0038] By controlling the movements of the winding roller 3 and the pressure roller 4 in this manner, the drum body 2 is rotated about the support shaft 2a while the support roller 7a, the winding roller 3, and the pressure roller 4 are moved in the width direction of the drum body 2, as illustrated in Fig. 7, and the strip material S is spirally wound around the outer circumferential surface of the tire component M. Immediately after being wound, the strip material S is pressed by the pressure roller 4 and is pressure-bonded to the outer circumferential surface of the tire component M and to the adjacently wound strip material S (overlapping strip material S).

[0039] When the strip material S is spirally wound, the control device 8 controls the speed ratio between the winding speed Vd of the strip material S around the drum 2 and the conveying speed Vf of the strip material S conveyed toward the drum 2. Basically, the winding speed Vd is set to be equal to or greater than the conveying speed Vf (Vd≧Vf), and by controlling the speed ratio Vd / Vf between the two, the degree of stretch of the strip material S immediately before being wound around the outer periphery of the drum 2 is kept within the appropriate range Ae. In addition, the temperature adjustment device 6 is controlled based on a comparison between the temperature detected by the temperature sensor 5 and a predetermined appropriate surface temperature range At. This ensures that the surface temperature of the strip material S immediately before being wound around the outer periphery of the drum 2 is kept within the appropriate range Ae.

[0040] More specifically, increasing the speed ratio Vd / Vf increases the degree of elongation of the strip material S, and decreasing the speed ratio Vd / Vf decreases the degree of elongation of the strip material S. The speed ratio Vd / Vf can be changed by changing the rotational speed of at least one of the winding roller 3 and the support roller 7a. By controlling the speed ratio Vd / Vf in this manner, the degree of elongation (elongation rate) of the strip material S immediately before being wound around the outer periphery of the drum body 2 falls within the appropriate range Ae.

[0041] Here, when the rotation speed (conveying speed Vf) of the support roller 7a is changed, the amount of strip material S present in the section from the tip of the extruder 1 to the support roller 7a located at the forefront position fluctuates. If the amount of strip material S present in this section is too small, there is a high risk that the strip material S being transported will break. If the amount of strip material S present in this section is too large, the time it takes for the transported strip material S to naturally cool will increase. If the amount of strip material S present in this section fluctuates, the time it takes for the transported strip material S to naturally cool will fluctuate, and as a result, the adhesive strength of the strip material S will change.

[0042] Therefore, in order to change the speed ratio Vd / Vf, it is preferable to keep the rotational speed of the support roller 7a constant (unchanged) and change only the rotational speed of the winding roller 3. This is advantageous in preventing breakage of the strip material S during transport and in suppressing variations in the surface temperature of the strip material S transported in the section immediately before winding.

[0043] To explain the control of the temperature regulator 6 in more detail, the surface temperature of the strip material S immediately after it has been conveyed through the section immediately before winding is detected by the temperature sensor 5. The temperature detected by this temperature sensor 5 is compared by the control device 8 with a predetermined optimum range At for the surface temperature. If this detected temperature is within the optimum range At, the temperature regulator 6 is not operated, but if it is not within the optimum range At, the temperature regulator 6 is operated. Generally, this optimum range At is between 30°C and 100°C, and more preferably between 40°C and 90°C.

[0044] If this detected temperature is not within the appropriate range At, the temperature control device 6 is operated to change the surface temperature of the strip material S being transported in the section just before winding, so that the surface temperature of the strip material S that has passed through the temperature control device 6 falls within the appropriate range At.

[0045] If the temperature detected by the temperature sensor 5 is lower than the lower limit of the appropriate surface temperature range At, the temperature adjustment device 6 is activated to increase the surface temperature of the strip material S being transported in the section just before winding, thereby increasing the adhesive strength of the surface of the strip material S. If the temperature detected by the temperature sensor 5 is higher than the upper limit of the appropriate surface temperature range At, the temperature adjustment device 6 is activated to decrease the surface temperature of the strip material S, thereby decreasing the adhesive strength of the surface of the strip material S.

[0046] To rapidly change the surface temperature of the strip material S, it is advisable to contact the strip material S with free rollers or the like that have a larger temperature difference with the strip material S being conveyed in the section immediately before winding. Therefore, as the temperature control device 6, for example, multiple heating rollers heated to 90°C or higher but lower than the surface temperature of the strip material S immediately after extrusion from the extruder 1 are arranged in the conveyance direction, and these heating rollers are brought into contact with the surface of the conveyed strip material S to raise the surface temperature. If the temperature detected by the temperature sensor 5 is lower than the lower limit of the appropriate range At and the difference is large, more heating rollers are brought into contact with the surface of the strip material S. If this difference is small, fewer heating rollers are brought into contact with the surface of the strip material S. If the temperature detected by the temperature sensor 5 is higher than the upper limit of the appropriate range At and the difference is large, more cooling rollers are brought into contact with the surface of the strip material S. If this difference is small, fewer cooling rollers are brought into contact with the surface of the strip material S. By controlling the temperature control device 6 in this manner, the surface temperature of the strip material S immediately before being wound around the outer periphery of the drum 2 is kept within the appropriate range At.

[0047] The surface (inner peripheral surface) of the strip material S that is wound facing the outer peripheral surface of the drum body 2 abuts against the outer peripheral surface of the tire component M that is placed on the outer peripheral surface of the drum body 2. If no tire component M is placed on the outer peripheral surface of the drum body 2, the inner peripheral surface of the strip material S abuts against the outer peripheral surface of the drum body 2. That is, the adhesive strength of the inner peripheral surface of the strip material S is important for firmly and stably winding the strip material S. Therefore, as in this embodiment, it is preferable to detect the temperature of the inner peripheral surface of the strip material S with a temperature sensor 5 and change that temperature with a control device 8.

[0048] In this embodiment, when the temperature control device 6 raises the surface temperature of the strip material S, substantially only the inner peripheral surface of the strip material S is heated. If the temperature of a larger portion of the strip material S changes (if a larger portion is heated), the tensile properties of the unvulcanized rubber forming the strip material S change, as illustrated in FIG. 3. Accordingly, even if the speed ratio Vd / Vf is controlled, it is disadvantageous to accurately bring the degree of elongation of the strip material S into the appropriate range Ae. From this perspective, it is preferable to detect the temperature of the inner peripheral surface of the strip material S with the temperature sensor 5 and substantially change the temperature of only this inner peripheral surface.

[0049] As described above, the degree of elongation and surface temperature of the strip material S immediately before being wound around the outer periphery of the drum body 2a are set to fall within the predetermined appropriate ranges Ae and At, respectively. That is, the speed ratio Vd / Vf and the temperature regulator 6 are controlled so that they fall within the appropriate ranges shown in FIG.

[0050] The spirally wound strip material S forms a tread joined to the outer peripheral surface of the tire component M, as illustrated in Fig. 8, to form a green tire G. Thereafter, the green tire G having the tire component formed from the strip material S is vulcanized in a vulcanizing device to manufacture a tire.

[0051] In this embodiment, the degree of elongation and surface temperature of the strip material S immediately before being wound around the outer periphery of the drum body 2 are set to appropriate ranges Ae and At, respectively, which are determined in advance for each rubber specification of the strip material S. As a result, the strip material S is wound around the drum body 2 (the outer periphery of the tire component M) with an appropriate winding force and with appropriate adhesiveness. Therefore, the strip material S is firmly and stably wound around the drum body 2 (the outer periphery of the tire component M), and overlapping portions of the strip material S are firmly joined, thereby suppressing collapse of the strip material S. As a result, correction work due to collapse of the strip material S is reduced, allowing for the molding of high-quality green tires G with high productivity. This is advantageous for manufacturing high-quality tires with high productivity.

[0052] Between controlling the degree of elongation of the strip material S (speed ratio Vd / Vf) and controlling the surface temperature of the strip material S (temperature control device 6), the former can be controlled more accurately. Therefore, if controlling either the former or the latter can bring the appropriate ranges Ae and At into the appropriate ranges, it is desirable to control only the former. In other words, in such cases, it is recommended to set the control of the degree of elongation of the strip material S (speed ratio Vd / Vf) to be given priority.

[0053] In the above embodiment, the tread is formed using the strip material S, but tire components other than the tread can also be formed. For example, this embodiment can be applied to form an inner liner layer, side rubber, etc. When forming an inner liner layer, since the tire component M is not disposed on the outer circumferential surface of the drum body 2, the strip material S is wound spirally directly around the outer circumferential surface of the drum body 2.

[0054] This embodiment is not limited to the case of manufacturing pneumatic tires, but can also be applied to the case of manufacturing various other types of tires. [Example]

[0055] Using molding equipment similar to that illustrated in Figures 1 and 2, green tires were formed by spirally winding strip material S, which would become the tread, around the outer periphery of a rigid core, as in the above-described embodiment. As shown in Table 1, the surface temperature of the strip material immediately before being wound around the drum (the temperature of the surface wound facing the outer periphery of the drum) and the elongation rate were varied in nine ways, but all other conditions were kept constant, and green tires (samples 1 to 9) of the same specifications were formed. The formed green tires were checked for the presence or absence of collapse of the strip material S, and the results are shown in Table 1.

[0056] The elongation percentages in Table 1 are calculated by dividing the elongation of the strip material S occurring in the section length between the support roller 7a and the winding roller 3 when the strip material S is pulled at the speed difference between the conveying speed Vf and the winding speed Vr by the section length. The cross-sectional shape of the strip material S is a wide, flattened rectangle, with a thickness / width ratio of approximately 0.1 and a cross-sectional area of ​​approximately 60 mm. 2 It was.

[0057] [Table 1]

[0058] The results in Table 1 show that in samples 5, 8, and 9, in which the degree of elongation (elongation rate) and surface temperature of the strip material just before wrapping it around the drum were set within the predetermined appropriate ranges Ae and At, respectively, the strip material did not collapse. [Explanation of symbols]

[0059] 1. Extruder 2 drum body 2a spindle 3 Winding roller 4 Pressure roller 5 Temperature Sensor 6 Temperature control device 7a, 7b, 7c Support roller 8 Control Device M Tire material S Strip material G Green Tire

Claims

1. A tire manufacturing method comprising spirally winding a strip of unvulcanized rubber around an outer periphery of a drum body to form a green tire, and then vulcanizing the green tire, The method for manufacturing a tire involves determining in advance the appropriate ranges for the degree of elongation and surface temperature of the strip material when it is wound around the outer periphery of the drum body, for each rubber specification of the strip material, and then winding the strip material around the outer periphery of the drum body with the degree of elongation and surface temperature within the appropriate ranges just before winding it around the outer periphery of the drum body.

2. A method for manufacturing a tire as described in claim 1, wherein the speed ratio between the winding speed of the strip material around the drum body and the conveying speed of the strip material being conveyed toward the drum body is controlled to keep the degree of stretch of the strip material within the appropriate range just before it is wound around the outer periphery of the drum body, and the surface temperature of the strip material being conveyed toward the drum body is detected by a temperature sensor, and a temperature control device is controlled based on a comparison between the detected temperature and the predetermined appropriate range of the surface temperature, so that the surface temperature of the strip material just before it is wound around the outer periphery of the drum body is kept within the appropriate range.

3. 3. The method for manufacturing a tire according to claim 1, wherein the surface temperature of the strip material is the temperature of the surface of the strip material that is wound facing the outer peripheral surface of the drum body.

4. 3. The tire manufacturing method according to claim 1, wherein the strip material has a cross-sectional shape that is flat and wide in the width direction of the drum body.

5. A tire manufacturing system including an extruder that extrudes a strip material of unvulcanized rubber, a drum body around which the strip material is spirally wound, and a vulcanizing device that vulcanizes a green tire having tire components formed from the spirally wound strip material, The apparatus includes a control device into which appropriate ranges of the degree of elongation of the strip material and its surface temperature when the strip material is wound onto the drum body, which are known in advance for each rubber specification of the strip material, are input, a temperature sensor that detects the surface temperature of the strip material being conveyed toward the drum body, and a temperature adjustment device, The control device controls the speed ratio between the winding speed of the strip material around the drum body and the conveying speed of the strip material being transported toward the drum body, so that the degree of stretch of the strip material just before it is wrapped around the outer periphery of the drum body is within the appropriate range, and the temperature adjustment device is controlled based on a comparison between the temperature detected by the temperature sensor and the predetermined appropriate range of the surface temperature, so that the surface temperature of the strip material just before it is wrapped around the outer periphery of the drum body is within the appropriate range.This is a tire manufacturing system.

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