Tire manufacturing method and system

Abstract

This invention provides a tire manufacturing method and system that suppresses the unwinding of unvulcanized rubber strip material wrapped around a drum body, thereby enabling the production of high-quality tires with high productivity. [Solution] For each rubber specification of the strip material S, the appropriate range of surface temperature when winding the strip material S onto the drum body 2 is determined in advance. Based on the extrusion temperature of the strip material S from the extruder 1 and the ambient temperature of the transport path from the extruder 1 to the drum body 2, the control device 8 calculates the rate of decrease in surface temperature of the strip material S over time. Based on this rate of decrease and the appropriate range, the control device 8 calculates the time required for the extrusion temperature and the transport path under those ambient temperatures to reach the appropriate range. The control device 8 then controls the length of the transport path or the transport speed so that the transport time for transporting the strip material S from the extruder 1, which is the starting point of the transport path, to the outer circumference of the drum body 2, which is the ending point, is the required time.

Description

Technical Field

[0001] The present invention relates to a method and a system for manufacturing a tire. More specifically, the present invention relates to a method and a system for manufacturing a tire that can suppress the unwinding of a strip material of unvulcanized rubber wound around a drum body in a tire molding process and manufacture a tire with excellent quality and high productivity.

Background Art

[0002] A method of forming a green tire by spirally winding a strip material of unvulcanized rubber around a molding drum is known (see, for example, Patent Document 1). In the invention proposed in Patent Document 1, a predetermined tension is applied to the strip material by making the pulling speed faster than the extrusion speed of the strip material, and the strip material is wound around the molding drum by making the pulling speed and the drum winding speed the same (paragraphs 0014 to 0015 of Patent Document 1). Thereby, the shrinkage amount of the strip material after being wound around the molding drum is reduced, and a rubber member having a desired shape is stably obtained.

[0003] However, since the tensile characteristics of the strip material differ depending on the rubber specification of the strip material, it is difficult to accurately apply a predetermined tension even if the extrusion speed and the pulling speed of the strip material are controlled in this way. Therefore, it is impossible to sufficiently suppress the unwinding of the strip material on the molding drum. And, since the strip material has a smaller cross-sectional area than an extruded material of general unvulcanized rubber used as tread rubber or side rubber, the rubber temperature (surface temperature) is likely to decrease in the conveyance path from the extruder to the molding drum. Along with this decrease in the surface temperature, the adhesive force of the strip material decreases, so that the strip material is likely to unwind. Therefore, there is room for improvement in suppressing the unwinding of the strip material of unvulcanized rubber wound around the molding drum.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

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

[0006] To achieve the above objective, the present invention provides a tire manufacturing method comprising forming a green tire by spirally winding an unvulcanized rubber strip around the outer circumference of a drum body, and vulcanizing the green tire, wherein for each rubber specification of the strip material, the appropriate range of winding temperature of the surface of the strip material when it is wound around the outer circumference of the drum body is determined in advance, the extrusion temperature of the surface when the strip material is extruded from the extruder and the ambient temperature of the transport path through which the strip material extends from the extruder to the drum body are calculated, the rate of decrease in the surface temperature over time under the extrusion temperature and ambient temperature is calculated, the time required for the winding temperature to reach the appropriate range in the transport path under the extrusion temperature and ambient temperature is calculated, and the transport time for transporting the strip material from the extruder, which is the starting point of the transport path, to the outer circumference of the drum body, which is the ending point, is controlled so that it is the required time.

[0007] The tire manufacturing system of the present invention comprises an extruder for extruding unvulcanized rubber strip material, a drum body around which the strip material is spirally wound, and a vulcanizing apparatus for vulcanizing a green tire having a tire member formed from the spirally wound strip material, wherein the system includes a control device that receives input for an appropriate range of surface winding temperature of the strip material when it is wound around the outer circumference of the drum body, which is known in advance for each rubber specification of the strip material, a temperature sensor that detects the extrusion temperature of the surface when the strip material is extruded from the extruder, and the extruder from the drum The control device includes a temperature sensor for detecting the ambient temperature of the transport path along which the strip material extends to the drum body, and a transport time adjustment mechanism for adjusting the transport time for transporting the strip material from the extruder, which is the starting point of the transport path, to the outer circumference of the drum body, which is the ending point. The control device calculates the rate of decrease over time of the surface temperature at the extrusion temperature and ambient temperature based on the extrusion temperature and ambient temperature, and calculates the time required for the winding temperature to reach the appropriate range in the transport path at the extrusion temperature and ambient temperature based on the calculated rate of decrease over time and the appropriate range. The transport time adjustment mechanism is controlled by the control device so that the transport time becomes the required time. [Effects of the Invention]

[0008] According to the present invention, the winding temperature of the surface of the strip material when it is wound around the outer circumference of the drum body is set to an appropriate range predetermined for each rubber specification of the strip material. As a result, the strip material is wound around the drum body with appropriate adhesiveness. Therefore, the strip material is firmly and stably wound around the drum body, suppressing unraveling. As a result, it is advantageous for manufacturing high-quality tires with good productivity. Furthermore, based on the rate of temperature decrease over time calculated by the control device and the appropriate range, the necessary time for the winding temperature to reach the appropriate range in the transport path under the extrusion temperature and ambient temperature is calculated, and the transport time is controlled to reach the necessary time. As a result, the winding temperature is set to the appropriate range in the transport path under the extrusion temperature and ambient temperature. Therefore, it is not necessary to cool the strip material during transport using special cooling means, which is advantageous for maintaining the quality of the strip material. [Brief explanation of the drawing]

[0009] [Figure 1] This is an explanatory diagram illustrating a molding process in a side view, illustrating an embodiment of a tire manufacturing system. [Figure 2] This is an explanatory diagram illustrating the upper half of the drum body around which the strip material is wound, along with the winding roller and crimping roller shown in Figure 1, in a cross-sectional view. [Figure 3] This graph illustrates the relationship between the temperature and adhesive strength of unvulcanized rubber used to form a strip material. [Figure 4] This graph illustrates the rate of temperature decrease over time in the unvulcanized rubber used to form the strip material. [Figure 5] This graph illustrates the relationship between the appropriate surface area of ​​the strip material and the transport time. [Figure 6] This is an explanatory diagram illustrating a method for adjusting the length of the transport path. [Figure 7] This is an explanatory diagram illustrating another method for adjusting the length of the transport path. [Figure 8]This is an explanatory diagram illustrating the schematic arrangement of the strip material wrapped around the drum body shown in Figure 2. [Figure 9] Figure 2 is an explanatory diagram illustrating the state in which a strip material wrapped around a drum body is being pressed by a compression roller. [Figure 10] Figure 9 is an explanatory diagram illustrating a green tire molded onto the outer surface of a drum body. [Modes for carrying out the invention]

[0010] The tire manufacturing method and system of the present invention will be described below based on the embodiments shown in the figures.

[0011] In the molding process illustrated in Figure 1, a green tire G is molded. The molded green tire G is then vulcanized by a vulcanizing apparatus in the vulcanization process to produce a tire T. Therefore, the embodiment of the tire manufacturing system includes molding equipment used in the molding process illustrated in Figure 1 and a vulcanizing apparatus used in the vulcanization process. Various known types of vulcanizing apparatus can be used, so their description is omitted.

[0012] The molding equipment illustrated in Figure 1 comprises an extruder 1, a drum body 2, temperature sensors 5a, 5b, and 5c (hereinafter collectively referred to as temperature sensors 5), a transport time adjustment mechanism 6, and a control device 8. The transport time adjustment mechanism 6 is located in the transport path between the extruder 1 and the drum body 2. Multiple support rollers 7a, 7b, 7c, and 7d (hereinafter collectively referred to as support rollers 7) are located in this transport path. A winding roller 3 and a crimping roller 4 are located near the outer circumferential surface of the drum 2.

[0013] The extruder 1 extrudes an unvulcanized rubber strip material S. This strip material S is conveyed toward the drum body 2. Various known types can be used for the extruder 1. A strip material S having a cross-sectional shape corresponding to the shape of the extrusion outlet of the die attached to the head of the extruder 1 is extruded. Various shapes can be adopted for the cross-sectional shape of the strip material S, such as a simple circular shape, an elliptical shape, a trapezoidal shape, a triangular shape, a rectangular shape, etc. The cross-sectional area of the strip material S is, for example, 25 mm , ,

[0016] or more and 70 mm 2 or less. In this embodiment, the cross-sectional shape of the strip material S is a wide flat shape (substantially rectangular shape). The thickness dimension / 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 draped over the support roller 7 arranged in front of the extruder 1. In this embodiment, four support rollers 7 are arranged, but the number thereof is not particularly limited and is set to an appropriate number. In this embodiment, each support roller 7 is a drive roller, but one or more of the support rollers 7 can be made into free rollers. The rotation of the support roller 7 is controlled by the control device 8. In this embodiment, the rotation of each support roller 7 is controlled individually. The rotation speed of the support roller 7 (the circumferential speed of the outer peripheral surface of the roller) becomes the conveyance 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 its cylindrical axis and extends in the width direction of the drum body 2. The drum body 2 rotates about the support shaft 2a. The strip material S conveyed 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 is wound around the outer peripheral side of the drum body 2.

[0016] Therefore, the section where the strip material S extends (the entire length of the strip material S) from the tip of the extruder 1 to the winding roller 3 (the outer peripheral side of the drum body 2 serving as the winding position) forms the conveyance path. In the section from the tip of the extruder 1 to the support roller 7a disposed at the foremost position, the strip material S is supported in a state of sagging between the respective support rollers. These support rollers 7 function as a festoon device for the strip material S.

[0017] Near the extrusion port of the extruder 1, a temperature sensor 5a is disposed. In this embodiment, the temperature sensor 5a is attached to the head of the extruder 1. This temperature sensor 5a detects the surface temperature (extrusion temperature) of the strip material S when the strip material S is extruded from the extruder 1. The extrusion temperature of the strip material S is, for example, about 90°C to 120°C. However, in this embodiment, the strip material S is naturally cooled while being conveyed along the conveyance path.

[0018] A temperature sensor 5b is disposed at an arbitrary position around the conveyance path. This temperature sensor 5b detects the ambient temperature (atmospheric temperature) of the conveyance path. This temperature sensor 5c is not essential and can be disposed arbitrarily. In this embodiment, since no cooling means for cooling the strip material S in the conveyance path is disposed, the change in the ambient temperature is small over the entire length of the conveyance path. Generally, the ambient temperature is 5°C or higher and 100°C or lower, or 20°C or higher and 50°C or lower. This temperature sensor 5b is disposed, for example, at an intermediate position between the extruder 1 and the drum body 2 (in the conveyance path).

[0019] In the transport path of the strip material S, the section from the support roller 7a to the winding roller 3 is the section immediately before winding. A temperature sensor 5c is positioned near this section immediately before winding. This temperature sensor 5c detects the surface temperature of the strip material S in the section immediately before winding. It is preferable that this temperature sensor 5c be positioned as close as possible to the drum body 2 in the transport path. The surface temperature of the strip material S in the section immediately before winding can be considered as the winding temperature when the strip material S is wound onto the outer circumference of the drum body 2. It is preferable that the temperature sensors 5a and 5c detect the temperature of the surface of the strip material S that is wound opposite the outer circumference of the drum body 2 (the inner circumference surface).

[0020] Various known non-contact temperature sensors can be used as the temperature sensor 5. The temperature detected by the temperature sensor 5 is sequentially input to the control device 8. In this embodiment, the strip material S is wrapped around the outer surface of the tire member M which is already placed on the outer surface of the drum body 2, but it may also be wrapped directly around the outer surface of the drum body 2. That is, since the strip material S is wrapped directly around the outer surface of the drum body 2 or indirectly via the tire member M, this specification states that the strip material S is wrapped around the outer surface of the drum body 2.

[0021] The transport time adjustment mechanism 6 adjusts the transport time for transporting the strip material S from the extruder 1, which is the starting point of the transport path, to the outer circumference of the drum body 2, which is the ending point. To adjust this transport time, the length of the transport path and / or the transport speed are adjusted using the transport time adjustment mechanism 6.

[0022] Position sensors 6a are positioned between each support roller 7 and above each support roller 7. These position sensors 6a detect the amount of sagging of the strip material S when it hangs down between each support roller 7. Various known non-contact distance sensors can be used as position sensors 6a. The amount of sagging of the strip material S detected by each position sensor 6a is sequentially input to the control device 8.

[0023] Since the front-to-back spacing between each support roller 7 is known, the control device 8 calculates the length of the strip material S hanging between the support rollers 7 based on the detection data from each position sensor 6a. The distance between the support rollers 7a and the winding roller 3 is also known, and the strip material S extends in a roughly straight line between them. Therefore, the control device 8 can sequentially calculate the length of the transport path. The length of the transport path of the strip material S is adjusted using the position sensors 6a and the support rollers 7. The transport speed of the strip material S is also adjusted using the support rollers 7. Therefore, in this embodiment, the position sensors 6a and the support rollers 7 constitute the transport time adjustment mechanism 6.

[0024] A strip material S is spirally wound around the outer circumference of the drum body 2. Therefore, the winding roller 3 and the crimping 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 the control device 8. If necessary, the support roller 7(7a) and the temperature sensor 5c also move in the width direction of the drum body 2 in the same manner. Alternatively, the support roller 7(7a), the winding roller 3 and the crimping roller 4 can be fixed in predetermined positions, and the drum body 2 can be configured to rotate around the support shaft 2a while moving in the width direction of the drum body 2.

[0025] As illustrated in Figure 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 member M is already formed on the outer circumferential surface of this drum body 2. This tire member M is formed by known methods using an inner liner, carcass material, a pair of beads, side rubber, belt material, etc., and is missing only the tread rubber. Therefore, in this embodiment, a strip material S is spirally wound around the outer circumferential surface of this tire member M as the tread rubber. The drum body 2 is not limited to a rigid core, and a molding drum commonly used in tire molding can also be used.

[0026] As illustrated in Figure 2, the winding roller 3 and the crimping roller 4 each have their rotation axes and outer surfaces inclined with respect to the support shaft 2a, but this inclination angle can be changed. In Figure 2, the rotation axes of the winding roller 3 and the crimping 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 crimping roller 4.

[0027] The winding roller 3 is a drive roller that rotates around its axis of rotation, and its rotation is controlled by the control device 8. The rotational speed of the winding roller 3 (circumferential speed of the outer surface of the roller) becomes the winding speed Vd of the strip material S onto the drum body 2. The circumferential speed of the outer surface of the drum body 2 at the position where the outer surface of the winding roller 3 faces is substantially the same as this winding speed Vd. More precisely, when winding the strip material S onto the outer surface of a tire member M already placed on the outer surface of the drum body 2, the circumferential speed of the outer surface of the tire member M at the position where the outer surface of the winding roller 3 faces is substantially the same as this winding speed Vd. When winding the strip material S directly onto the outer surface of the drum body 2, the circumferential speed of the outer surface of the drum body 2 at the position where the outer surface of the winding roller 3 faces is substantially the same as this winding speed Vd.

[0028] The crimping roller 4 rolls along the surface of the strip material S immediately after it has been wrapped around the outer circumference of the drum body 2 by the winding roller 3, and presses against the strip material S. The crimping roller 4 is a free roller that rotates around its axis of rotation.

[0029] 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, the appropriate range At of the surface temperature (winding temperature) of the strip material S when winding the strip material S onto the drum body 2 is known in advance. In addition, the rate of temperature decrease over time of the unvulcanized rubber (strip material S) under a predetermined extrusion temperature and a predetermined ambient temperature is known in advance.

[0030] This section will explain the temperature decrease over time in the unvulcanized rubber (strip material S) within the appropriate temperature range At. First, we will explain the appropriate temperature range At.

[0031] The surface temperature of the strip material S when it is wrapped around the drum body 2 affects the degree to which the strip material S, once wrapped around the drum body 2, adheres to the outer surface of the drum body 2 (the outer surface of the tire member M positioned on the outer surface of the drum body 2a). If the adhesion is strong, the strip material S will be firmly and stably wrapped around the drum body 2 (the tire member M positioned on the outer surface of the drum body 2a), while if the adhesion is weak, the strip material S will be in an unstable wrapped state.

[0032] However, if the surface temperature of the strip material S is excessively high, the strip material S may unnecessarily adhere to adjacent components or equipment along the transport path, hindering smooth transport. Furthermore, if the strip material S is too soft, unwanted deformation may occur. Therefore, it is necessary to set the surface temperature of the strip material S immediately before winding it onto the outer surface of the drum body 2 to an appropriate range At. Generally, this appropriate range At is 30°C to 100°C, more preferably 40°C to 90°C.

[0033] As illustrated in Figure 3, the relationship between the adhesive strength of the unvulcanized rubber forming the strip material S and the rubber temperature is generally such that the adhesive strength increases as the rubber temperature rises. Figure 3 shows the relationship between adhesive strength and rubber temperature for unvulcanized rubbers Sa and Sb with different rubber specifications. The degree of change in adhesive strength with respect to rubber temperature (the slope of the data) differs depending on the rubber specifications. This adhesive strength is proportional to the adhesion force of the strip material S. The appropriate lower limit Hn and upper limit Hx of the adhesive strength when winding the strip material S onto the drum body 2 are the same regardless of the rubber specifications, and these lower limit Hn and upper limit Hx can be determined by prior testing, etc. Therefore, the appropriate range At of rubber temperature (surface temperature) when winding the strip material S onto the drum body 2 differs for each rubber specification. This appropriate range At is input and stored in the control device 8.

[0034] Next, we will explain the rate at which the temperature of the unvulcanized rubber (strip material S) decreases over time.

[0035] The strip material S extruded from the extruder 1 is hot immediately after extrusion, but if left in an ambient temperature lower than the extrusion temperature, it gradually cools naturally and eventually becomes the same as the ambient temperature. As illustrated in Figure 4, the rate of temperature decrease over time of the unvulcanized rubber forming the strip material S differs depending on the extrusion temperature and ambient temperature, even if the rubber specifications are the same. In Figure 4, for unvulcanized rubber with the same rubber specifications, the solid line SLa shows the rate of temperature decrease over time when the extrusion temperature is a predetermined high temperature at a predetermined low ambient temperature tL, the solid line SLb shows the rate of temperature decrease over time when the extrusion temperature is a predetermined low temperature at a predetermined low ambient temperature tL, and the dashed line SLa shows the rate of temperature decrease over time when the extrusion temperature is a predetermined high temperature at a predetermined high ambient temperature tH. The solid line SLb and the dashed line SHb have the same extrusion temperature.

[0036] The data in Figure 4 differs slightly depending on the rubber specifications of the unvulcanized rubber (strip material S). Therefore, it is preferable to understand the data for each rubber specification, but it is also acceptable to use data for a representative rubber specification rather than for each specification. The elapsed time in Figure 4 can be considered as the time from when the strip material S is extruded from the extruder 1 until it is wrapped around the outer circumference of the drum body 2. In other words, the elapsed time in Figure 4 can be considered as the transport time during which the strip material S is transported from the start to the end of the transport path.

[0037] Therefore, taking into consideration the data in Figure 3 and Figure 4, preliminary tests and analyses are conducted, and based on the results, the relationship between the temperature of the unvulcanized rubber (strip material S) and the elapsed time (transport time) (data SD shown by the solid line) for each rubber specification, extrusion temperature, and ambient temperature of the unvulcanized rubber forming the strip material S is determined (data SD shown by the solid line). Figure 5 shows that when the winding temperature of the strip material S is within the appropriate range At under a predetermined extrusion temperature and ambient temperature, the transport time (elapsed time) is between Mn and Mx. The data SD exemplified in Figure 5 is input to and stored in the control device 8.

[0038] The following describes an example of the procedure for molding green tire G using the molding equipment shown in Figure 1.

[0039] As illustrated in Figure 6, when winding the strip material S spirally around the outer circumference of the drum body 2, in this embodiment, the extrusion temperature of the surface of the strip material S when it is extruded from the extruder 1 is detected by the temperature sensor 5a and sequentially input to the control device 8. In addition, the ambient temperature of the transport path detected by the temperature sensor 5b is sequentially input to the control device 8. Based on the input extrusion temperature and ambient temperature, the control device 8 calculates the corresponding data SD, illustrated in Figure 5, as the rate of decrease over time of the surface temperature of the strip material S under these extrusion temperatures and ambient temperatures. That is, the data SD corresponding to the extrusion temperature and ambient temperature is selected and identified from the data SD stored in the control device 8. Then, based on the calculated rate of decrease over time (data SD) and the appropriate range At, the control device 8 calculates the time required for the winding temperature of the strip material S to reach the appropriate range At under those extrusion temperatures and in the transport path under those ambient temperatures.

[0040] Here, the control device 8 controls the transport time for transporting the strip material S from the extruder 1, which is the starting point of the transport path, to the outer circumference of the drum body 2, which is the ending point, so that the transport time becomes the calculated required time. Since the transport time depends on the length of the transport path and the transport speed, the control device 8 adjusts the length of the transport path and / or the transport speed so that the transport time becomes the calculated required time.

[0041] To adjust the length of the transport path, as illustrated in Figure 6, the amount of sagging of the strip material S is detected by the position sensor 6a, and the rotation speed of the support rollers 7 is controlled to increase or decrease the amount of sagging of the strip material S, thereby changing the transport length. That is, if the total amount of sagging of the strip material S between each support roller 7 increases, the transport length increases, and if the total amount of sagging decreases, the transport length decreases. It is also possible to control the amount of sagging of the strip material S between specific support rollers 7 to be different from the amount of sagging of the strip material S between other support rollers 7, but basically, it is best to make the amount of sagging of the strip material S between each support roller 7 the same. This makes it easier to maintain a consistent quality of the strip material S. In addition, to avoid complicating the control, it is basically best to adjust the length of the transport path while keeping the transport speed constant. The length of the transport path can be adjusted independently of the rotation speed Vd of the winding roller 3. Therefore, there is an advantage in that it does not affect the molding time of the green tire G.

[0042] To adjust the length of the transport path, instead of the position sensor 6a, a dancer roller 6b can be used, as illustrated in Figure 7. The dancer roller 6b is positioned between each support roller 7 and moves up and down. Each dancer roller 6b is moved to a desired vertical position by the control device 8. Each dancer roller 6b constitutes the transport time adjustment mechanism 6. When adjusting the length of the transport path, the transport length is changed by increasing or decreasing the amount of sagging of the strip material S by controlling the vertical position of each dancer roller 6b with the control device 8. Furthermore, control is taken to prevent unnecessary stretching deformation from occurring in the strip material S as the dancer roller 6b moves downward.

[0043] To adjust the transport speed so that the transport time is the calculated required time, the rotation speed of the support roller 7 and the winding roller 3 are changed. That is, the transport speed is increased by increasing the rotation speed of the support roller 7 and the winding roller 3, and the transport speed is increased or decreased by decreasing the rotation speed of the support roller 7 and the winding roller 3. To avoid complicating the control, it is best to adjust the transport speed while keeping the transport length constant.

[0044] In this embodiment, the winding temperature of the strip material S is detected by a temperature sensor 5c. The detected winding temperature is input to the control device 8 to determine whether or not it is within the appropriate range At. If the winding temperature detected by the temperature sensor 5c is outside the appropriate range At, the control device 8 activates a warning means (such as an alarm or warning display) to inform the operator that the winding temperature is outside the appropriate range At.

[0045] At the destination of the strip material S, the strip material S is spirally wound around the outer circumference of the drum body 2. Since a tire member M is already formed on this drum body 2, the strip material S is wound around the outer circumference of the tire member M. As illustrated in Figure 8, the strip material S is spirally wound so as to slightly overlap the drum body 2 in the width direction. Therefore, in a cross-sectional view of the drum body 2, the outer circumference of the wound strip material S is slightly inclined with respect to the outer circumference of the tire member M (drum body 2). This inclination angle of the strip material S is known in advance. In addition, the cross-sectional shape (profile) of the outer circumference of the tire member M (drum body 2) is known in advance.

[0046] Therefore, when winding the strip material S in a spiral shape, the control device 8 controls the inclination angle of the central axis (outer surface) of the winding roller 3 and the crimping roller 4, respectively, based on the predetermined profile and the inclination angle of the strip material S relative to this profile. As a result, the outer surfaces of the winding roller 3 and the crimping roller 4 are made substantially parallel to the outer surface of the strip material S wound around the outer surface of the tire member M.

[0047] By controlling the movement of the winding roller 3 and the crimping roller 4 in this manner, as illustrated in Figure 9, the drum body 2 is rotated around the support shaft 2a, while the support roller 7a, the winding roller 3, and the crimping roller 4 are moved in the width direction of the drum body 2, thereby spirally winding the strip material S around the outer circumferential surface of the tire member M. Immediately after winding, the strip material S is pressed by the crimping roller 4 and pressed against the outer circumferential surface of the tire member M and adjacently wound strip material S (overlapping strip material S).

[0048] As illustrated in Figure 10, a tread is formed by spirally wound strip material S, which is joined to the outer surface of the tire member M, thereby forming a green tire G. Subsequently, this green tire G, which has the tire member formed from the strip material S, is vulcanized using a vulcanizing apparatus to manufacture a tire.

[0049] As described above, in this embodiment, the winding temperature of the surface of the strip material S is adjusted to an appropriate range At, so that the strip material S is wound around the drum body 2 (outer surface of the tire member M) with appropriate adhesiveness. Therefore, the strip material S is firmly and stably wound around the drum body 2 (outer surface of the tire member M), and the overlapping parts of the strip material S are firmly joined together, so that the unwinding of the strip material S is suppressed. Accordingly, the amount of corrective work caused by the unwinding of the strip material S is reduced. Furthermore, problems such as the strip material S unnecessarily adhering to adjacent members or equipment in the transport path due to an excessively high surface temperature (excessive viscosity) and hindering smooth transport, as well as unnecessary deformation, can be avoided. As a result, high-quality green tires G can be formed with high productivity. Consequently, it is advantageous for manufacturing high-quality tires with high productivity.

[0050] The control device 8 calculates the time required for the winding temperature to reach the appropriate range At, given the extrusion temperature of the strip material S and the ambient temperature of the transport path, and controls the transport time to match this required time. Therefore, there is no need to cool the strip material S during transport using special cooling means. In other words, in this embodiment, the strip material S is naturally cooled at its ambient temperature. If the strip material S is forcibly cooled using cooling means, there is a risk of problems such as condensation forming on the surface of the strip material S or localized cooling occurring. On the other hand, when the strip material S is naturally cooled at its ambient temperature as in this embodiment, such problems do not occur, and the surface temperature of the strip material S can be stably kept within the appropriate range At. Consequently, this is advantageous for maintaining the quality of the strip material S.

[0051] The extrusion temperature of the strip material S changes depending on the rubber specifications and extrusion conditions of the strip material S, and the temperature of the strip material S during transport changes depending on the ambient temperature of the transport path. Furthermore, simply detecting the extrusion temperature of the strip material S does not allow for accurate estimation of the winding temperature. Also, even if the temperature of the strip material S immediately before winding it onto the drum body 2 is detected, it is difficult to set the winding temperature within the appropriate range At. However, according to this embodiment, even if there are differences in the rubber specifications and extrusion conditions of the strip material S, and even if the temperature of the strip material S changes during transport, it becomes possible to wind the strip material S onto the drum body 2 (outer surface of the tire member M) at a winding temperature within the appropriate range At.

[0052] The inner surface of the strip material S that is wrapped opposite the outer surface of the drum body 2 contacts the outer surface of the tire member M that is placed on the outer surface of the drum body 2. If the tire member M is not placed on the outer surface of the drum body 2, the inner surface of the strip material S contacts the outer surface of the drum body 2. In other words, the adhesive force of the inner surface of the strip material S is important for firmly and stably wrapping the strip material S. Therefore, as in this embodiment, it is preferable to detect the temperature of the inner surface of the strip material S with a temperature sensor 5a and set this inner surface to an appropriate range At when wrapping it around the outer surface of the drum body 2.

[0053] In the above embodiment, the tread is formed by the strip material S, but it is also possible to form tire components other than the tread. For example, this embodiment can be applied to form an inner liner layer, side rubber, etc. When forming an inner liner layer, since no tire components M are placed 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 can be applied not only to the manufacture of pneumatic tires, but also to the manufacture of various other types of tires. [Explanation of Symbols]

[0055] 1. Extruder 2 drum bodies 2a spindle 3. Winding roller 4 Crimping rollers 5(5a, 5b, 5c) Temperature sensor 6. Conveying time adjustment mechanism 6a Position sensor 6b Dancer Laura 7(7a, 7b, 7c, 7d) Support roller 8 Control device M Tire component S strip material G Green Tire

Claims

1. In a tire manufacturing method in which an unvulcanized rubber strip is spirally wound around the outer circumference of a drum body to form a green tire, and this green tire is vulcanized, For each rubber specification of the strip material, the appropriate range of surface temperature for winding the strip material around the outer circumference of the drum body is determined in advance. Based on the extrusion temperature of the surface when the strip material is extruded from the extruder and the ambient temperature of the transport path through which the strip material extends from the extruder to the drum, the rate of decrease over time of the extrusion temperature and the surface temperature under the ambient temperature is calculated. Based on the calculated rate of decrease over time and the appropriate range, the time required for the winding temperature to reach the appropriate range in the conveying path under the extrusion temperature and ambient temperature is calculated. A tire manufacturing method comprising controlling the transport time for transporting the strip material from the extruder, which is the starting point of the transport path, to the outer circumference of the drum body, which is the ending point, so that the transport time becomes the required time.

2. A method for manufacturing a tire according to claim 1, wherein the length of the transport path is adjusted to control the transport time so that it becomes the required time.

3. The method for manufacturing a tire according to claim 1 or 2, wherein the surface is a surface that is wrapped around the outer circumferential surface of the drum body of the strip material opposite to the outer circumferential surface.

4. The method for manufacturing a tire according to claim 1 or 2, wherein the cross-sectional shape of the strip material is a wide, flat shape in the width direction of the drum body.

5. A tire manufacturing system comprising an extruder for extruding unvulcanized rubber strip material, a drum body around which the strip material is spirally wound, and a vulcanizing apparatus for vulcanizing a green tire having a tire member formed from the spirally wound strip material, A control device that receives input the appropriate range of surface temperature of the strip material when it is wound around the outer circumference of the drum body, which is known in advance for each rubber specification of the strip material, A temperature sensor for detecting the extrusion temperature of the surface when the strip material is extruded from the extruder, and a temperature sensor for detecting the ambient temperature of the transport path through which the strip material extends from the extruder to the drum body, The system includes a transport time adjustment mechanism for adjusting the transport time for transporting the strip material from the extruder, which is the starting point of the transport path, to the outer circumference of the drum body, which is the ending point. The control device calculates the rate at which the surface temperature decreases over time based on the extrusion temperature and the ambient temperature, and calculates the time required for the winding temperature to reach the appropriate range in the transport path under the extrusion temperature and the ambient temperature, based on the calculated rate at which the temperature decreases over time and the appropriate range. A tire manufacturing system in which the transport time adjustment mechanism is controlled by the control device so that the transport time becomes the required time.

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