Method and apparatus for manufacturing raw tire

Abstract

To obtain a method for manufacturing a green tire and an apparatus for manufacturing the green tire capable of reducing air pockets.SOLUTION: A method for manufacturing a green tire incudes: winding a textile treat 32 around a molding drum in a circumferential direction, and overlapping and bonding both end portions 34A and 34B in a winding direction to each other to form a bonded portion 38; and winding a ribbon 46 around the textile treat 32 in a direction to run over a step 36 of an end portion positioned radially outside of both end portions that constitute the bonded portion 38 to laminate on the textile treat 32.SELECTED DRAWING: Figure 5

Description

[Technical field]

[0001] The present disclosure relates to a raw tire manufacturing method and an apparatus for manufacturing a raw tire. [Background technology]

[0002] Patent Document 1 describes a pneumatic tire for motorcycles having at least one spiral belt layer formed of a spirally wound structure in which a ribbon-shaped strip is extended in the circumferential direction of the tire and wound in a spiral shape. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2012-228995 A Summary of the Invention [Problem to be solved by the invention]

[0004] In pneumatic tires, particularly pneumatic tires for motorcycles, the center in the tire width direction is curved so as to be convex toward the outer periphery, that is, when viewed in a cross section including the tire center axis, the tread surface is curved so as to bulge radially outward.

[0005] When manufacturing a raw pneumatic tire having such a shape, a strip (sometimes called a textile treat) is wound circumferentially around the outer periphery of an annular case (molding drum), and then a ribbon is wound and laminated around the wound strip.

[0006] As described above, when the tire cross section is curved, it is difficult to butt-join the two ends of the winding method of the band. For this reason, a structure is adopted in which the two ends of the winding method of the band are overlapped and joined. However, when the two ends of the winding method of the band are overlapped, a step is generated at the joint.

[0007] If the above-mentioned step occurs when winding and stacking the ribbon onto the wound strip, this step may cause a gap, or a so-called air pocket, between the strip and the ribbon.

[0008] An object of the present application is to provide a raw tire manufacturing method and a raw tire manufacturing apparatus capable of reducing air pockets. [Means for solving the problem]

[0009] In the first embodiment of the raw tire manufacturing method, a band-like body is wound circumferentially around a building drum, and both end portions in the winding direction are overlapped and joined to form a joint, and a ribbon is wound around the band-like body in a direction that rides up the step at the end portion located radially outward of the both end portions that constitute the joint, and stacked around the band-like body.

[0010] In this raw tire manufacturing method, both ends of the band in the winding direction are overlapped and joined together to form a joint. Therefore, a stronger joint can be achieved compared to a configuration in which both ends of the band in the winding direction are butted together and joined. For example, even in a tire that is curved such that the center in the tire width direction is convex toward the outer periphery, both ends of the band in the winding direction can be reliably joined.

[0011] In addition, in this raw tire manufacturing method, a ribbon is wound and laminated on the band wound on the building drum. At this time, a step is generated at the joint of the band at the end located on the radially outer side of both ends constituting the joint. Since the ribbon is wound in a direction that rides up the step, the ribbon is more likely to get into the step compared to a configuration in which the ribbon is wound in the opposite direction, i.e., in a direction that rides down the step. In other words, it is possible to reduce air pockets due to the step.

[0012] In a second embodiment, the width of the ribbon along the axial direction of the forming drum is 15 mm or more and 24 mm or less.

[0013] When stacking a ribbon on a strip, the center of the ribbon width is often pressed. By making the ribbon width 24mm or less, the area away from both ends of the ribbon width, i.e., the pressed area at the center of the ribbon width, can be reduced compared to when the ribbon width is more than 24mm, and the area where the ribbon can be pressed strongly onto the strip can be secured. This allows the ribbon to be inserted reliably into the gap.

[0014] In addition, by making the ribbon width 15 mm or more, a larger winding area can be secured per winding compared to when the width is less than 15 mm, which reduces the number of turns required to cover the outer periphery of the strip, improving productivity.

[0015] In a third embodiment, the ribbon is wound around the band-shaped body with widthwise ends of the ribbons overlapping each other by 10% to 70% of the width of the ribbons between adjacent ribbons in the axial direction of the forming drum.

[0016] By making the overlapping portion of the ribbon 10% or more of the width, a wider overlapping portion in the width direction of the ribbon can be secured compared to when it is less than 10%. Since the overlapping portion of the ribbon is larger, it can be reliably fitted into the step of the strip-shaped body. Also, by making the overlapping portion of the ribbon 70% or less of the width, compared to when it is more than 70%, excessive overlapping does not occur in one winding, so the number of turns can be reduced and productivity can be improved.

[0017] In a fourth embodiment, the thickness of the ribbon along the radial direction of the forming drum is 1.0 mm or more and 1.8 mm or less.

[0018] A ribbon thickness of 1.0 mm or more ensures a sufficient thickness, i.e., a sufficient amount of raw rubber, to enter the gap, compared to a ribbon thickness of less than 1.0 mm. Also, a ribbon thickness of 1.8 mm or less reduces the step at the overlapping portion of the ribbon itself on the outer periphery of the ribbon, compared to a ribbon thickness of more than 1.8 mm.

[0019] In a fifth embodiment, the height of the step along the radial direction of the forming drum is 1.0 mm or more and 6.0 mm or less.

[0020] By setting the height of the step to 6.0 mm or less, the step is smaller than when it exceeds 6.0 mm, so air pockets due to the step can be reduced. Also, since the step is substantially formed by the thickness of the strip, a configuration in which the step height is 1.0 mm or more ensures that the strip is substantially thick. And even if the strip is thick, air pockets due to the step can be reduced.

[0021] In a sixth aspect, the ribbon is laminated on the band-shaped body by applying a pressing pressure of 0.4 MPa or more and 0.6 MPa or less along the radial direction of the forming drum.

[0022] By setting the pressing pressure on the ribbon to 0.4 MPa or more, the ribbon can be inserted into the gap more reliably than when the pressing pressure is less than 0.4 MPa. Also, by setting the pressing pressure on the ribbon to 0.6 MPa or less, excessive pressing on the ribbon can be suppressed, preventing deformation of the ribbon, compared to when the pressing pressure exceeds 0.6 MPa.

[0023] In a seventh aspect, the overlapping portion is pressed in a direction climbing over the step to join the two end portions of the strip.

[0024] Since the overlapping portion is pressed in a direction to ride over the step of the overlap, the step is formed so that the surface of the step is inclined toward the outside in the tire radial direction. This makes it possible to form a step shape that allows the ribbon to easily enter the step.

[0025] The eighth embodiment of the raw tire manufacturing apparatus includes a forming drum, a band winding device that winds a band circumferentially around the forming drum and overlaps and joins both ends in the winding direction to form a joint, and a ribbon winding device that winds a ribbon around the band wound around the forming drum by the band winding device in a direction that rides up the step at the end that is located radially outward of the both ends that constitute the joint, thereby stacking it on the band.

[0026] In this raw tire manufacturing apparatus, the band winding device winds the band in the circumferential direction on the building drum. At this time, the band winding device overlaps both ends in the winding direction and joins them to form a joint. Therefore, a stronger joint can be achieved compared to a configuration in which both ends in the winding direction of the band are butted together and joined. For example, even in a tire that is curved such that the center in the tire width direction is convex toward the outer periphery, both ends in the winding direction of the band can be reliably joined.

[0027] Then, the ribbon is wound onto the band-shaped body by the ribbon winding device. At the joint of the band-shaped body, a step occurs at the end located on the radially outer side of both ends constituting the joint. Since the ribbon winding device winds the ribbon in a direction that climbs up the step, the ribbon is more likely to get into the step compared to a configuration in which the ribbon is wound in the opposite direction, i.e., in a direction that climbs down the step. In other words, it is possible to reduce air pockets caused by the step.

[0028] In a ninth aspect, the band winding device presses the overlapping portions in a direction climbing up the step when joining the two end portions of the band.

[0029] The ribbon winding device presses the overlapping portion in a direction that rides over the step of the overlap, so that the step is formed so that the surface of the step is inclined toward the outside in the tire radial direction. This makes it possible to form a step shape that makes it easy for the ribbon to enter the step. Effect of the Invention

[0030] The present application provides a raw tire manufacturing method and a raw tire manufacturing apparatus capable of reducing air pockets. [Brief description of the drawings]

[0031] [Figure 1] FIG. 1 is a schematic diagram showing a raw tire manufacturing apparatus according to the first embodiment. [Diagram 2] FIG. 2 is a cross-sectional view showing a green tire manufactured by the green tire manufacturing apparatus of the first embodiment. [Diagram 3]FIG. 3 is a schematic cross-sectional view showing an enlarged joint portion of a textile treat formed by the raw tire building apparatus of the first embodiment. [Figure 4] FIG. 4 is a schematic view showing, in an enlarged part, the ribbon winding device of the green tire building apparatus of the first embodiment. [Diagram 5] FIG. 5 is a schematic cross-sectional view showing, in an enlarged manner, a winding portion of the ribbon configured by the raw tire building apparatus of the first embodiment. [Figure 6] FIG. 6 is a schematic cross-sectional view showing, in an enlarged scale, an overlapping portion of ribbons formed by the raw tire building apparatus of the first embodiment. [Figure 7] FIG. 7 is a schematic cross-sectional view showing, in an enlarged scale, a winding portion of a ribbon configured by the raw tire manufacturing apparatus of the first comparative example. [Figure 8] FIG. 8 is a schematic cross-sectional view showing an enlarged joint portion of a textile treat formed by the raw tire building apparatus of the second embodiment. [Figure 9] FIG. 9 is a schematic cross-sectional view showing an enlarged joint portion of a textile treat formed by the green tire manufacturing apparatus of the second comparative example. [Figure 10] FIG. 10 is a schematic diagram showing a modified example of a ribbon winding device according to the technique disclosed in the present application. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0032] Hereinafter, an example of an embodiment of the present application will be described in detail with reference to the drawings.

[0033] Fig. 1 shows a green tire manufacturing apparatus 22 of the first embodiment. Fig. 2 shows a green tire 12 manufactured by the green tire manufacturing apparatus 22. This green tire 12 is a green tire obtained in the process of manufacturing pneumatic tires for motorcycles, and has a shape curved such that the center in the tire width direction (arrow W1 direction) is convex outward (arrow S1 direction) when viewed in a cross section including the tire center axis.

[0034] 1, a raw tire manufacturing apparatus 22 of the first embodiment has a textile treat winding device 24 and a ribbon winding device 26. The textile treat winding device 24 is an example of a band-like winding device.

[0035] In the textile treat winding device 24, a forming drum 28 (see ribbon winding device 26 shown on the right side of Fig. 1) used in manufacturing the green tire 12 is rotated in a fixed direction by a rotary drive device (not shown). When this forming drum 28 is viewed in a cross section including the central axis of rotation, the outer periphery of the forming drum 28 is curved so that the center in the width direction is convex outward in correspondence with the green tire 12 (see Fig. 2). The axial direction of the forming drum 28 coincides with the tire width direction (direction of arrow W1).

[0036] A textile treat 32 is supplied onto the forming drum 28 by a supplying device (not shown) and is wound around the drum 28 in the circumferential direction by the winding roller 30. The textile treat 32 is an example of a belt-like textile. The width of the winding roller 30 is wider than the width of the textile treat 32.

[0037] The textile treat 32 is, for example, a long member extending in a direction along the outer circumferential surface of the forming drum 28, and is wound around the forming drum 28 while being pulled in the longitudinal direction. In this case, the length of the textile treat 32 may be shorter than the length of the outer circumferential surface of the forming drum 32, but the textile treat 32 may be longer in the winding direction than the length of the outer circumferential surface of the forming drum 28. Then, as shown in FIG. 3, both ends in the winding direction (start end 34A and end end 34B) are overlapped. In the next process, the overlapped parts are pressed and joined by a pressing roller 31 to form a joint 38. In the joint 38, the textile treat 32 is two-layered, with a lower layer treat 32L located on the inner circumferential side of the forming drum 28 and an upper layer treat 32U located on the outer circumferential side. The end end 34B is a step 36 in the textile treat 32.

[0038] In the first embodiment, the pressing direction of the overlapping portion by the pressing roller 31 has a large component in the thickness direction (arrow T1 direction) of the textile treat 32. Therefore, after the pressing roller 31 presses the overlapping portion, the end portion 34B stands up approximately perpendicular to the lower layer treat 32L. In the example shown in Fig. 1, the width of the pressing roller 31 is narrower than the width of the textile treat 32. In this case, the pressing roller 31 is moved in the width direction of the forming drum 28 while pressing the overlapping portion, so that the overlapping portions can be joined over the entire width direction to form a joint 38.

[0039] The forming drum 28, now wrapped with the textile treat 32, is then fed to the ribbon winding device 26, as shown in FIG.

[0040] The ribbon winding device 26 has an extruder 40, a holding roller 42, and a stretching roller 44. Also in the ribbon winding device 26, the forming drum 28 is rotated in a fixed direction (the direction of the arrow R2) by a rotation drive device (not shown).

[0041] The extruder 40 extrudes raw rubber 48 that constitutes a ribbon 46, which will be described later, from an extrusion die 50. The holding roller 42 is disposed at a fixed interval from the forming drum 28. The holding roller 42 is rotated in the opposite direction to the forming drum 28 by a rotary drive device (not shown).

[0042] The raw rubber 48 extruded from the extrusion die 50 is stretched to a predetermined width and thickness between the holding roller 42 and the stretching roller 44 to form a band-shaped ribbon 46. This ribbon 46 is sent between the holding roller 42 and the forming drum 28. Then, while being held by the holding roller 42, the ribbon 46 is wound around the textile treat 32 in the circumferential direction as the forming drum 28 rotates in the direction of arrow R2. Note that the stretching roller 44 may be omitted.

[0043] Here, the forming drum 28 rotates in the direction of the arrow R2, and the winding direction of the ribbon 46 is the direction in which the ribbon 46 climbs up the step 36 (the direction of the arrow M1). This "direction in which the ribbon 46 climbs up the step 36" is also the direction in which the ribbon 46 is stacked in order from the lower layer treat 32L to the upper layer treat 32U.

[0044] The width W2 of the ribbon 46 (see FIG. 6) is narrower than the width of the raw tire 12, but the ribbon 46 is continuous in the longitudinal direction, i.e., in the extrusion direction from the extrusion die 50. In the ribbon winding device 26, the ribbon 46 is wound and laminated spirally multiple times on the textile treat 32 while being moved at a predetermined speed between winding positions in the tire width direction. In this manner, the ribbon 46 can cover the outer periphery of the textile treat 32. The width W2 of the ribbon 46 is the length in the direction perpendicular to the longitudinal direction of the ribbon 46. The width W2 is also the length of the ribbon 46 along the axial direction of the forming drum 28 and the length in the direction perpendicular to the extrusion direction.

[0045] Next, the operation of the first embodiment will be described.

[0046] In the green tire building apparatus 22 of the first embodiment, the textile treat winding device 24 winds the textile treat 32 onto the building drum 28 .

[0047] With the textile treat 32 wound in this manner, the overlapping portions of the textile treat 32 are pressed by a pressing roller 31 to be joined (stitched), and a joint 38 is formed as shown in FIG. 3. Therefore, it is possible to achieve a stronger joint than, for example, a structure in which the starting end 34A and the ending end 34B of the textile treat 32 are simply butted together without being overlapped. In particular, in a raw tire for a pneumatic tire for a motorcycle such as the first embodiment, the tire outer circumferential surface is curved in the tire width direction as shown in FIG. 2, so that it is often difficult to butt together both ends (the starting end 34A and the ending end 34B) of the textile treat 32. In contrast, if the textile treat 32 is overlapped at both ends, the textile treat 32 can be strongly joined at the starting end 34A and the ending end 34B.

[0048] When the textile treat 32 is overlapped in this manner to form the joint 38, a step 36 is created in the textile treat 32 at the end portion 34B, as shown in FIG.

[0049] 4 and 5, the ribbon winding device 26 winds a ribbon 46 around the textile treat 32. The forming drum 28 rotates in the direction of arrow R2, and the ribbon 46 is wound around the textile treat 32 in a direction (arrow M1 direction) that climbs up the step 36. As a result, part of the raw rubber that constitutes the ribbon 46 enters the gap G that occurs between the ribbon 46 and the textile treat 32, and this gap G becomes smaller.

[0050] Here, FIG. 7 shows the relationship between the step 36 and the winding direction of the ribbon 46 in the green tire manufacturing apparatus of the first comparative example.

[0051] In the first comparative example, the rotation direction of the forming drum 28 (the direction indicated by the arrow R2) is opposite to that of the first embodiment shown in Fig. 5, and the winding direction of the ribbon 46 (the direction indicated by the arrow M2) is the direction in which the ribbon 46 rides down the step 36. That is, the ribbon 46 is wound in the direction in which the upper layer treat 32U is stacked on the lower layer treat 32L in order. Therefore, in the gap G, a force acts on the ribbon 46 in a direction away from the step 36, and the gap G becomes larger. As the gap G becomes larger in this way, the air pocket due to the step 36 also becomes larger.

[0052] In contrast, in the first embodiment, the winding direction of the ribbon 46 is a direction that rides up the step 36, as shown by the arrow M1 in Fig. 5. Therefore, a force acts on the ribbon 46 in the portion of the gap G in a direction approaching the step 36, and the raw rubber of the ribbon 46 enters the portion where the gap G occurs, resulting in a smaller gap G. Since the gap G is thus smaller in the first embodiment, the air pocket caused by the step 36 is also smaller than in the comparative example.

[0053] In particular, in the first embodiment, once the rotation direction (arrow R2 direction) of the forming drum in the ribbon winding device is set, the winding direction of the ribbon 46 can be easily determined as the opposite direction to the rotation direction of the forming drum .

[0054] Next, a second embodiment will be described. In the second embodiment, the same elements, members, etc. as those in the first embodiment are denoted by the same reference numerals, and detailed description thereof will be omitted. In addition, since the overall configuration of the raw tire manufacturing apparatus of the second embodiment is the same as that of the first embodiment, illustration thereof will be omitted.

[0055] In the second embodiment, the configuration of the textile treat winding device is different from that in the first embodiment. Specifically, in the second embodiment, as partially shown in Fig. 8, the pressing direction of the pressing roller 31 (the direction in which the overlapping portion of the textile treat 32 is pressed) has a larger component of the direction climbing up the step 36 (the direction of the arrow M1) compared to the first embodiment.

[0056] For example, when joining the joint portion 38, the pressing roller 31 presses the joint portion 38 while rotating the forming drum 28 in the direction of the arrow R1 shown in Fig. 1. In this case, if the forming drum 28 is rotated at a sufficient rotation speed, the pressing roller 31 will have a relatively larger pressing component in the direction of the arrow M1. Also, the central axis of the pressing roller 31 may be biased in the direction of the arrow M1 by a spring or the like (not shown). This makes it possible to give the pressing direction of the pressing roller 31 a component in the direction of the arrow M1.

[0057] In the second embodiment, this causes the surface forming the step 36, that is, the terminal end 34B, to be inclined so as to face outward in the tire radial direction.

[0058] Here, FIG. 9 shows a joint of a textile treat 32 joined by the textile treat winding device of the second comparative example.

[0059] In the second comparative example, the pressing direction of the pressing roller 31 has a larger component in the direction of riding over the step 36 (the direction of the arrow M2). Therefore, the surface forming the step 36, i.e., the end portion 34B, is inclined so as to face inward in the tire radial direction. In other words, the inclination angle θ of the end portion 34B becomes an acute angle. Therefore, when the ribbon 46 is wound by the ribbon winding device 26 (see FIG. 1), the raw rubber constituting the ribbon 46 is less likely to enter the gap G (see FIG. 5).

[0060] In contrast, in the second embodiment, as shown in Fig. 8, the inclination angle θ of the end portion 34B of the textile treat 32 is an obtuse angle. Therefore, when the ribbon 46 is wound by the ribbon winding device 26 (see Fig. 1), the raw rubber constituting the ribbon 46 easily enters the gap G (see Fig. 5), making it possible to realize a structure in which air pockets are smaller.

[0061] In the technology disclosed in the present application, different types of ribbons 46 may be wound around the textile treat 32. For example, the raw tire 12 shown in Fig. 2 is an example in which different types of ribbons 46 are wound around the textile treat 32. Specifically, the winding direction of the ribbon 46 is different between the portion from the center 12M in the tire width direction to the shoulder portion 12L on the left side of the drawing and the shoulder portion 12R on the right side of the drawing.

[0062] When manufacturing such a green tire 12, an additional extruder 60 may be disposed on the radially opposite side of the extruder 40 in the ribbon winding device 26, as in a modified example shown in Fig. 10. When winding the ribbon 46 sent from the opposing extruder 60 around the textile treat 32, the forming drum 28 is rotated in the direction of arrow R3. Therefore, the ribbon 46 is wound around the textile treat 32 in a direction that rides down the step 36 relative to the textile treat 32 (a direction from the upper layer treat 32U to the lower layer treat 32L shown in Fig. 3).

[0063] In this way, when the winding direction of the ribbon 46 includes both a direction climbing up the step 36 and a direction climbing down the step 36, an appropriate winding direction of the ribbon 46 may be set, for example, taking into consideration the usage state of the final motorcycle pneumatic tire. As an example, in a motorcycle pneumatic tire, the center portion in the tire width direction is the portion that contacts the ground when traveling in a straight line, i.e., when traveling at high speed. Therefore, the winding direction (the rotation direction of the forming drum 28) may be set so that the ribbon 46 is wound in the center portion in the tire width direction in the direction climbing up the step 36.

[0064] In the technology disclosed in the present application, the height of the step 36, the width W2, thickness T2, overlap rate, and pressing pressure on the ribbon 46 can be, for example, within the ranges shown in Table 1. Note that the overlap rate referred to here is the ratio of the length of the overlapping portion W3 to the width W2 of the ribbon 46 when viewed in a cross section including the tire centerline, as shown in Fig. 6. Also, the pressing pressure on the ribbon 46 is the pressure acting on the overlapping portion of the ribbon 46 and the textile treat 32 in the radial direction of the forming drum 28.

[0065] [Table 1]

[0066] For example, when the ribbon 46 is layered on the textile treat 32 by the holding roller 42, the outer peripheral surface of the holding roller 42 is cylindrical, whereas the outer peripheral surface of the forming drum 28 is curved convexly toward the outer peripheral side. Therefore, if the ribbon 46 is wide, it is difficult to press both sides of the ribbon 46 in the width direction into contact with the textile treat 32. By setting the width of the ribbon 46 to 24 mm or less, the area of ​​both ends of the ribbon 46 in the width direction, i.e., the area far from the pressing portion in the center in the width direction, can be reduced compared to when the width of the ribbon 46 is more than 24 mm, and an area in which the ribbon 46 can be strongly pressed onto the textile treat 32 can be secured. This allows the raw rubber of the ribbon 46 to reliably enter the gap G.

[0067] Furthermore, by making the width W2 of the ribbon 46 15 mm or more, a larger winding area can be secured per winding, compared to when the width is less than 15 mm. This reduces the number of turns required to cover the outer periphery of the textile treat 32 with the ribbon 46, improving productivity.

[0068] Moreover, by setting the overlap rate, i.e., the ratio of the overlapping portion in the width direction of the ribbon 46, to 10% or more of the width W2, the overlapping portion in the width direction of the ribbon 46 becomes wider compared to when it is less than 10%. Since the overlapping portion of the ribbon 46 is large, a sufficient amount of raw rubber can be secured in the ribbon 46 to reliably enter the gap G. Furthermore, by setting the overlap rate of the ribbon 46 to 70% or less, compared to when it is more than 70%, an excessive overlapping portion is not generated in one winding, so that the number of turns of the ribbon 46 can be reduced and productivity can be improved. Note that the "overlapped portion" referred to here is a portion where the ends of two ribbons 46 adjacent to each other in the width direction of the forming drum 28 (for example, the nth ribbon 46 and the (n+1)th ribbon 46 in the width direction) overlap each other in the width direction.

[0069] By setting the thickness T2 of the ribbon 46 to 1.0 mm or more, it is possible to ensure a sufficient thickness of the ribbon 46, i.e., an amount of raw rubber 48, to enter the gap G, compared to when the thickness is less than 1.0 mm. Also, by setting the thickness of the ribbon 46 to 1.8 mm or less, the step at the overlapping portion of the ribbon 46 itself generated on the outer periphery of the ribbon 46 is smaller, compared to when the thickness exceeds 1.8 mm.

[0070] By setting the height of the step 36 to 6.0 mm or less, the step is smaller than when the height exceeds 6.0 mm. This makes it possible to reduce air pockets caused by the step 36. Furthermore, the step 36 is formed substantially by the thickness of the textile treat 32. Therefore, a configuration in which the height of the step 36 is 1.0 mm or more is a configuration in which the thickness of the textile treat 32 is substantially ensured. Even in such a configuration in which the thickness of the textile treat 32 is increased, the technology disclosed in the present application can reduce air pockets caused by the step 36.

[0071] By setting the pressing pressure applied by the holding roller 42 to the ribbon 46 (pressure for pressing the ribbon 46 against the textile treat 32) at 0.4 MPa or more, the ribbon 46 can be reliably inserted into the gap G, compared to a case where the pressure is less than 0.4 MPa. Furthermore, by setting the pressing pressure applied by the ribbon 46 to 0.6 MPa or less, the ribbon 46 can be prevented from being excessively pressed and deformation of the ribbon 46 can be prevented, compared to a case where the pressure exceeds 0.6 MPa. However, the pressing pressure applied by the holding roller 42 to the ribbon 46 is preferably 0.4 MPa or more and 0.6 MPa or less, but is not limited to this range. In short, it is sufficient that the ribbon 46 can be reliably inserted into the gap G, and for example, the pressing pressure may be less than 0.4 MPa. Furthermore, in order to reliably insert the ribbon 46 into the gap G, a pressing pressure of more than 0.6 MPa may be used.

[0072] The height of the step 36 and the respective values ​​related to the ribbon 46 described above can be appropriately combined within their respective ranges. For example, even if the height of the step 36 is 6 mm, as long as the thickness of the ribbon 46 is 1.0 mm or more, it is possible to ensure that the ribbon 46 has a sufficient thickness to enter the gap G. Also, even if the height of the step 36 is 1 mm and the thickness of the ribbon 46 is 1.8 mm or more, the step at the overlapping portion of the ribbon 46 itself generated on the outer circumferential side of the ribbon 46 can be kept within the range allowable for the raw tire 12. [Explanation of symbols]

[0073] Reference Signs List 12: Raw tire, 22: Raw tire manufacturing device, 24: Textile treat winding device, 26: Ribbon winding device, 28: Forming drum, 30: Winding roller, 31: Press roller, 32: Textile treat, 32L: Lower layer treat, 32U: Upper layer treat, 34A: Starting end, 34B: End end, 36: Step, 38: Joint, 46: Ribbon, 48: Raw rubber

Claims

1. The strip is wound around the forming drum in a circumferential direction, and both ends in the winding direction are overlapped and joined to each other to form a joint; a ribbon is wound around the band-shaped body in a direction to ride up a step of an end portion located radially outward of the two end portions constituting the joint, and laminated on the band-shaped body; A method for manufacturing raw tires.

2. 2. The method for manufacturing a green tire according to claim 1, wherein a width of the ribbon along the axial direction of the building drum is 15 mm or more and 24 mm or less.

3. 3. The raw tire manufacturing method according to claim 1, wherein the ribbon is wound around the band-shaped body such that ends of the ribbons in the width direction adjacent to each other in the axial direction of the building drum overlap each other by 10% to 70% of the width of the ribbon.

4. The raw tire manufacturing method according to any one of claims 1 to 3, wherein a thickness of the ribbon along a radial direction of the building drum is 1.0 mm or more and 1.8 mm or less.

5. The raw tire manufacturing method according to any one of claims 1 to 4, wherein a height of the step along the radial direction of the building drum is 1.0 mm or more and 6.0 mm or less.

6. The raw tire manufacturing method according to any one of claims 1 to 5, wherein the ribbon is laminated on the band-shaped body with a pressing pressure of 0.4 MPa or more and 0.6 MPa or less along the radial direction of the building drum.

7. The raw tire manufacturing method according to any one of claims 1 to 6, further comprising pressing the overlapping portion in a direction climbing over the step to join the two end portions of the belt-shaped body.

8. A forming drum; a band winding device that winds a band around the forming drum in a circumferential direction and overlaps and joins both ends in the winding direction to form a joint; a ribbon winding device that winds a ribbon around the strip wound around the forming drum by the strip winding device in a direction that rides up a step at an end located radially outward of the two end portions that constitute the joint, and stacks the ribbon on the strip; A raw tire manufacturing apparatus comprising:

9. The raw tire manufacturing apparatus according to claim 8 , wherein the band-like body winding device presses the overlapping portion in a direction climbing up the step to join the two end portions of the band-like body.

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