JP7461825B2 - Manufacturing method and manufacturing device for pneumatic tire - Google Patents

Description

The present invention relates to a method and apparatus for manufacturing pneumatic tires.

In the manufacture of pneumatic tires, tire components such as the inner liner and carcass ply are wound around a building drum to form a cylindrical carcass band. The carcass band has beads attached to both ends and is folded back around the beads to form a cylindrical green case. Meanwhile, tire components such as the belt and tread are wound around another building drum to form a cylindrical tread band.

Then, after the tread band is transported radially outward of the green case, the green case is expanded radially outward to bond with the inner surface of the tread band, and the green tire is molded. The molded green tire is vulcanized and molded by a vulcanization molding device, and a pneumatic tire is manufactured.

Patent Document 1 discloses that when manufacturing pneumatic tires, an inner liner is used in which chafers are placed on both sides of the butyl rubber in the width direction and a tie gum is pressed to cover the butyl rubber and both chafers.

Patent document 1 also discloses that, in order to close the gap formed between the butyl rubber and the chafer, a pressure roller is used to press the area between the butyl rubber and the chafer at the joint where both circumferential ends of the inner liner are joined.

JP2018-051891A

When manufacturing pneumatic tires, chafers, such as steel chafers, may be placed on both sides in the width direction between the inner liner and the carcass ply. In this case, when the inner liner, both chafers, and the carcass ply are wound sequentially around the molding drum to mold the carcass band, air may accumulate near the inner end of the chafer between the inner liner and the carcass ply, causing air to accumulate in the pneumatic tire. In particular, when steel chafers are placed, this problem may become more pronounced. Furthermore, when manufacturing pneumatic tires, it is desirable to manufacture them with high productivity.

The present invention aims to provide a method and device for manufacturing pneumatic tires that can be manufactured with high productivity while preventing air from accumulating near the inner end of the chafer between the inner liner and the carcass ply.

The present invention provides a method for manufacturing a pneumatic tire, which sequentially winds an inner liner, chafers on both sides spaced apart from each other in the width direction on the inner liner, and a carcass ply formed wider than the inner ends of the chafers on both sides and placed on the inner liner and the chafers on both sides around a molding drum, and while pressing the carcass ply from the outer surface side with a roller, moves the roller from the center side of the carcass ply in the width direction to the outer end side in the width direction while rotating the molding drum, and makes the feed pitch of the roller that moves the roller smaller in a predetermined width range of the carcass ply including the inner end of the chafer than the center side and the outer end side in the width direction of the carcass ply.

When manufacturing a pneumatic tire with this configuration, the roller presses the inner liner, both chafers, and carcass ply that are wound around the building drum in sequence from the outer surface side, while moving the roller from the center side of the width of the carcass ply to the outer end of the width direction while rotating the building drum.

The roller feed pitch is made smaller in a specified range in the width direction of the carcass ply, including the inner end of the chafer, compared to the width direction center side and width direction outer end side of the carcass ply, so the roller moves less compared to when the roller feed pitch is not made smaller, making it easier for the roller to radially deform the carcass ply along the inner liner and chafer near the step formed in the carcass ply by the inner end of the chafer. The roller feed pitch is the distance the roller moves in the axial direction of the molding drum, i.e., in the width direction of the carcass ply 4, when the molding drum rotates once.

As a result, when the roller is moved from the widthwise center of the carcass ply to the widthwise outer end thereof to move and discharge the air present between the inner liner and the carcass ply to the widthwise outer side of the carcass ply, the air present between the inner liner and the carcass ply can be easily moved widthwise outward from the inner end of the chafer, and air accumulation between the inner liner and the carcass ply near the inner end of the chafer can be suppressed.

In addition, the roller feed pitch is smaller in a specified range of the width of the carcass ply, including the inner end of the chafer, compared to the width center and width outer end of the carcass ply. This reduces the roller feed time required to move the roller from the width center to the width outer end of the carcass ply, compared to when the roller feed pitch is also smaller at the width center or width outer end of the carcass ply, allowing for more productive manufacturing.

This allows for efficient production while preventing air from accumulating near the inner end of the chafer between the inner liner and the carcass ply.

The chafer may be a steel chafer.

This configuration effectively prevents air from accumulating near the inner end of the chafer between the inner liner and the carcass ply when the steel chafer is placed between the inner liner and the carcass ply. The effect of the present invention is best achieved when a steel chafer, which is more prone to air accumulation than a nylon chafer, is placed.

A splice tape is disposed between the chafer and the carcass ply to cover the inner end of the chafer in the width direction, and it is preferable that the feed pitch of the roller is smaller in a predetermined range in the width direction of the carcass ply including the splice tape than in the center side in the width direction and the outer end side in the width direction of the carcass ply.

This configuration increases the bonding strength between the chafer and the carcass ply with the bonding tape, and suppresses changes in strength caused by the chafer of the pneumatic tire at the inner end of the chafer that is placed between the inner liner and the carcass ply. Even when the bonding tape is placed between the chafer and the carcass ply, it is possible to manufacture with good productivity while suppressing air accumulation near the inner end of the chafer between the inner liner and the carcass ply.

The pressure applied by the roller to the carcass ply can be increased in a predetermined widthwise range of the carcass ply, including the inner end of the chafer, compared to the widthwise center of the carcass ply.

With this configuration, the pressing force of the roller is increased in a predetermined widthwise range of the carcass ply, including the inner end of the chafer, compared to the widthwise center of the carcass ply, so that the roller deforms the carcass ply more radially along the inner liner and chafer near the step formed in the carcass ply by the inner end of the chafer, and air accumulation near the inner end of the chafer can be further suppressed.

The carcass ply may be pressed from the outer side by a first roller formed to be wider than the widthwise inner ends of the chafers on both sides and narrower than the widthwise outer ends of the carcass ply on both sides, and then the second roller may be moved from the widthwise center side of the carcass ply to the widthwise outer end while rotating the molding drum, while pressing the carcass ply from the outer side by a second roller. The second roller may have a smaller feed pitch in a predetermined widthwise range of the carcass ply including the inner end of the chafer compared to the widthwise center side and widthwise outer end side of the carcass ply, and the first roller may be formed to have a lower hardness than the second roller.

With this configuration, the first roller is formed with a lower hardness than the second roller, so the first roller easily deforms the carcass ply in the radial direction along the inner liner and the chafer, and the first roller easily moves the air between the inner liner and the carcass ply outward in the width direction from the inner end of the chafer. Since the first roller is formed narrower than the outer ends of the carcass ply on both sides, the first roller easily moves the air between the inner liner and the carcass ply outward in the width direction from the inner end of the chafer in the width direction, compared to when the first roller is formed wider than the outer ends of the carcass ply on both sides. Furthermore, the second roller can move the air outward in the width direction from the outer ends of the carcass ply in the width direction and discharge it, which further suppresses air from accumulating near the inner end of the chafer between the inner liner and the carcass ply.

The present invention also provides a pneumatic tire manufacturing device that includes an inner liner, two chafers arranged on the inner liner at a distance from each other in the width direction, a molding drum on which the inner liner and the carcass ply arranged on the two chafers are wound in sequence, the inner liner being wound in sequence around the inner liner and the carcass ply being wound on the two chafers in the width direction, and a roller formed in a width narrower than the inner ends of the two chafers in the width direction, the inner liner, the two chafers, and the carcass ply being wound in sequence around the molding drum are pressed from the outer surface side by the roller, the roller is moved from the center side of the width direction of the carcass ply to the outer end side of the width direction while rotating the molding drum, and the feed pitch of the roller that moves the roller is made smaller in a predetermined width direction range of the carcass ply including the inner end of the chafer than the center side of the width direction and the outer end side of the carcass ply.

According to the present invention, the effects of the invention relating to the manufacturing method of pneumatic tires are exhibited in the manufacturing device for pneumatic tires.

The manufacturing method and manufacturing device for pneumatic tires according to the present invention can produce tires with high productivity while preventing air from accumulating near the inner end of the chafer between the inner liner and the carcass ply.

1 is a schematic side view of a pneumatic tire manufacturing apparatus according to a first embodiment of the present invention. FIG. 2 is a schematic front view of a pneumatic tire manufacturing apparatus. FIG. 2 is a cross-sectional view showing a tire component wound around a building drum. FIG. 4 is an explanatory diagram for explaining the winding process of the inner liner, the chafer, and the carcass ply. FIG. 11 is an explanatory diagram for explaining a roller pressing step. FIG. 6 is a cross-sectional view showing a tire constituent member wound around a building drum according to a second embodiment of the present invention. FIG. 11 is an explanatory diagram for explaining a roller pressing step. FIG. 11 is a cross-sectional view showing a tire constituent member wound around a building drum according to a third embodiment of the present invention. FIG. 11 is a schematic side view of a pneumatic tire manufacturing apparatus according to a fourth embodiment of the present invention. FIG. 2 is a schematic front view of a pneumatic tire manufacturing apparatus. 6A to 6C are explanatory diagrams for explaining a pressing step of a first roller.

Hereinafter, an embodiment of the present invention will be described with reference to the accompanying drawings.
In the manufacture of a pneumatic tire according to an embodiment of the present invention, an inner liner, both side chafers, and a carcass ply are wound around a building drum to form a cylindrical carcass band. The molded carcass band is then moved to another building drum and held there, after which beads are assembled to both sides of the carcass band and folded back around the beads, and sidewall rubber is wound around the carcass band to form a cylindrical green case. Meanwhile, a belt and tread rubber are wound around another building drum in this order to form a cylindrical tread band.

Then, after the tread band is transported radially outward of the green case, the green case is expanded radially outward into a toroidal shape and joined to the inner surface of the tread band, forming a green tire. The molded green tire is then vulcanized and molded by a vulcanization molding device to produce a pneumatic tire.

Figure 1 is a schematic side view of a pneumatic tire manufacturing apparatus according to a first embodiment of the present invention. Figure 2 is a schematic front view of a pneumatic tire manufacturing apparatus. As shown in Figures 1 and 2, the manufacturing apparatus 1 for manufacturing pneumatic tires according to the first embodiment of the present invention winds tire components, including an inner liner, chafers on both sides, and a carcass ply, around a molding drum in sequence to mold a cylindrical carcass band.

The manufacturing device 1 includes a molding drum 10 on which the inner liner 2, the chafers 3 on both sides, and the carcass ply 4 are wound in sequence, a drum drive device 11 that drives the molding drum 10 to rotate, and a supply device 20 that supplies the inner liner 2, the chafers 3 on both sides, and the carcass ply 4 in sequence to the molding drum 10.

Figure 3 is a cross-sectional view showing the tire components wound around the building drum. As shown in Figure 3, the inner liner 2, the chafers 3 on both sides, and the carcass ply 4 are wound around the building drum 10 in sequence by the supply device 20 to form a cylindrical carcass band 5.

Figure 4 is an explanatory diagram for explaining the winding process of the inner liner, chafer, and carcass ply. In Figure 4, the tire components are shown spaced apart in the radial direction. As shown in Figure 4, when manufacturing a pneumatic tire, first, the inner liner 2 is supplied to the molding drum 10, and the inner liner 2 is wound cylindrically around the molding drum 10.

Next, the chafers 3 on both sides, spaced apart in the width direction, are simultaneously fed onto the forming drum 10, and the chafers 3 on both sides are wound cylindrically onto the inner liner 2. The chafers 3 on both sides are formed so that at least the inner end 3a in the width direction is positioned widthwise inward relative to the outer end 2a in the width direction of the inner liner 2.

Then, the carcass ply 4 is supplied to the forming drum 10, and the carcass ply 4 is wound cylindrically on the inner liner 2 and the chafers 3 on both sides. The carcass ply 4 is formed wider than the widthwise inner ends 3a of the chafers 3 on both sides, and the widthwise outer ends 4a on both sides are positioned widthwise outward of the widthwise inner ends 3a of the chafers 3 on both sides. The inner liner 2, chafers 3, and carcass ply 4 are formed symmetrically with respect to the widthwise center line L1 of the carcass ply 4.

In this embodiment, the carcass ply 4 is formed so that the widthwise outer ends 4a on both sides are located widthwise inward of the widthwise outer ends 3b of the chafers 3 on both sides. The inner liner 2 is formed so that the widthwise outer ends 2a on both sides are located widthwise outward of the widthwise outer ends 3b of the chafers 3 on both sides.

The chafers 3 on both sides are arranged between the inner liner 2 and the carcass ply 4, spaced apart on both sides in the width direction. Each of the chafers 3 on both sides is a steel chafer, which is a band-shaped sheet made of rubber-coated steel cords arranged in parallel at intervals. Although the chafers 3 on both sides are steel chafers, it is also possible to use nylon chafers using organic fiber cords.

As shown in FIG. 3, when the inner liner 2, the chafers 3 on both sides, and the carcass ply 4 are wound around the molding drum 10 in sequence, the center side of the carcass ply 4 in the width direction is overlapped with the inner liner 2 between the chafers 3 on both sides, and the outer sides on both sides in the width direction are overlapped with the chafers 3 on both sides that are overlapped with the inner liner 2. Therefore, the chafers 3 on both sides form step portions between the center side in the width direction and the outer sides in the width direction on both sides of the carcass ply 4.

The drum drive device 11 uses a motor 11 that rotates the molding drum 10 around the drum central axis C1. Instead of a motor, it is also possible to use another drum drive device that rotates the molding drum 10 as the drum drive device 11. The drum drive device 11 is capable of changing the rotation speed of the molding drum 10.

As shown in FIG. 1, the supply device 20 is configured to supply the inner liner 2, the chafers 3 on both sides, and the carcass ply 4 to the building drum 10 by guiding them with the guide portions 21.

The manufacturing device 1 also includes a pressing device 30 that presses the inner liner 2, the chafers 3 on both sides, and the carcass ply 4, which are wound sequentially around the molding drum 10, from the outer surface side.

As shown in Figs. 1 and 2, the pressing device 30 includes a pair of rollers 31 formed in a cylindrical shape, a shaft 32 that rotatably supports each of the pair of rollers 31, and a moving mechanism 33 that moves the shaft 32 in the radial and axial directions of the molding drum 10. The moving mechanism 33 includes a support portion 34 that fixes and supports the shaft 32, and is configured to be able to move the support portion 34 in the radial and axial directions of the molding drum 10 to move the rollers 31 in the axial and radial directions of the molding drum 10.

The movement mechanism 33 may include, for example, a motor and a ball screw, and converts the rotation of the motor into radial and axial movement via the ball screw to move the support part 34 in the radial and axial directions of the molding drum 10.

The rollers 31 are configured to be movable in the radial direction of the molding drum 10 between a radial outer position shown by a solid line in FIG. 1 and a radial inner position shown by a two-dot chain line in FIG. 1 by a moving mechanism 33, and are configured to be movable in the axial direction of the molding drum 10 between an axial inner position shown by a solid line in FIG. 2 and an axial outer position shown by a two-dot chain line in FIG. 2. Each roller 31 is configured to move from an axial inner position to an axial outer position while pressing the carcass ply 4 wound around the molding drum 10 from the outer surface side at the radial inner position.

The movement mechanism 33 is capable of changing the speed at which the roller 31 moves in the axial direction of the building drum 10 and the pressing force with which the roller 31 presses the carcass ply 4 from the outer surface side.

The roller 31 is formed with a hardness of 48 HDA or more and 52 HDA or less. If the hardness of the roller 31 is less than 48 HDA, the roller 31 is less likely to press against the carcass ply 4, and the air present between the inner liner 2 and the carcass ply 4 is less likely to move widthwise outward from the widthwise inner end 3a of the chafer 3. In addition, deformation such as wrinkles and damage to the roller 31 are more likely to occur. On the other hand, if the hardness of the roller 31 is greater than 52 HDA, the roller 31 is less likely to bounce off the widthwise inner end 3a of the chafer 3 and press along the widthwise inner end 3a of the chafer 3, and the air present between the inner liner 2 and the carcass ply 4 is less likely to move widthwise outward from the widthwise inner end 3a of the chafer 3.

The hardness is the hardness (HDA) measured based on JIS K7311 using a type A durometer specified in JIS K7215. The roller 31 is formed using, for example, non-foamed urethane resin. The roller 31 may have, for example, an outer diameter of 135 to 145 mm and a width of 12 to 20 mm.

Figure 5 is an explanatory diagram for explaining the roller pressing process. As shown in Figure 5, the rollers 31 of the pressing device 30 are each formed narrower than the inner end 3a of the chafers 3 on both sides in the width direction, specifically narrower than half the distance between the inner end 3a of the chafers 3 on both sides in the width direction.

The pressing device 30 moves a pair of rollers 31 radially inward from the widthwise inner position of the forming drum 10 to the inner side of the inner liner 2, the chafers 3 on both sides, and the carcass ply 4 that are wound sequentially around the forming drum 10, and presses the carcass ply 4 from the outer surface side with the rollers 31.

The axially inner position of the roller 31 is preferably a position where the axially inner end of the roller 31 is the widthwise centerline L1 of the carcass ply 4, but the axially outer end of the roller 31 is set to be at least a widthwise inner side of the first predetermined position P1 of the carcass ply 4 that is widthwise inner than the inner end 3a of the chafer 3 shown in Figure 4 described later.

Then, while pressing the carcass ply 4 from the outer surface side with the roller 31, the roller 31 is moved from the widthwise center side of the carcass ply 4, which is inside the widthwise inner end 3a of the chafer 3, to the widthwise outer end 4a of the carcass ply 4, specifically, to the widthwise outer side of the widthwise outer end 4a of the carcass ply 4, while rotating the molding drum 10.

While rotating the molding drum 10, one roller 31 presses the carcass ply 4 from the outer surface side and moves it from the widthwise inner side of the widthwise inner end 3a of one chafer 3 to the widthwise outer side of one widthwise outer end 4a of the carcass ply 4, while the other roller 31 presses the carcass ply 4 from the outer surface side and moves it from the widthwise inner side of the widthwise inner end 3a of the other chafer 3 to the widthwise outer side of the other widthwise outer end 4a of the carcass ply 4.

When the roller 31 is moved from the widthwise inner position to the widthwise outer side of the carcass ply 4, while the molding drum 10 is rotated at a constant rotational speed R1 as shown in FIG. 5, the roller 31 is moved at a moving speed V1 at the widthwise center side of the carcass ply 4, at a moving speed V2 in a predetermined widthwise range of the carcass ply 4 including the inner end 3a of the chafer 3 between the widthwise center side and the widthwise outer end side of the carcass ply 4, and at a moving speed V3 at the widthwise outer end side of the carcass ply 4.

As shown in FIG. 4, the widthwise center side of the carcass ply is set to a range from the widthwise centerline L1 of the carcass ply 4 to a first predetermined position P1 at a distance X1 on the widthwise outer side of the carcass ply 4, the widthwise predetermined range of the carcass ply 4 between the widthwise center side and the widthwise outer end side of the carcass ply 4 is set to a range from the first predetermined position P1 to a second predetermined position P2 at a distance X2 on the widthwise outer side of the carcass ply 4, and the widthwise outer end side range of the carcass ply 4 is set to a range from the second predetermined position P2 to a third predetermined position P3 at a distance X3 on the widthwise outer side of the carcass ply 4 from the widthwise centerline L1 of the carcass ply 4.

The first predetermined position P1 is set on the inside in the width direction of the carcass ply 4 from the fourth predetermined position P4, which is the inner end 3a of the chafer 3 at a distance X4 from the width direction center line L1 of the carcass ply 4 to the outside in the width direction of the carcass ply 4, and the second predetermined position P2 is set on the outside in the width direction of the carcass ply 4 from the fourth predetermined position P4.

The first predetermined position P1 and the second predetermined position P2 are set at equal or approximately equal distances from the fourth predetermined position P4 in the width direction of the carcass ply 4. The distance between the fourth predetermined position P4 and the first predetermined position P1 and the distance between the fourth predetermined position P4 and the second predetermined position P2 are set to, for example, 25 mm to 35 mm. Distances X1, X2, X3, and X4 from the width direction center line L1 of the carcass ply 4 are set to, for example, 160 mm, 210 mm, 305 mm, and 185 mm, respectively.

In this embodiment, the movement speed of the roller 31 is set lower in a predetermined widthwise range of the carcass ply 4 including the inner end 3a of the chafer 3 compared to the widthwise center side and widthwise outer end side of the carcass ply 4, and the movement speed V2 of the roller 31 is set lower than the movement speeds V1 and V3 of the roller 31. The movement speeds V1 and V3 of the roller 31 are set to the same speed. The movement speed V3 of the roller 31 can also be set to a speed lower or higher than the movement speed V1 of the roller 31.

Since the molding drum 10 rotates at a constant rotational speed R1, the feed pitch of the roller 31 that moves the roller 31 in the width direction of the carcass ply 4 is made smaller in a predetermined range in the width direction of the carcass ply 4, including the inner end 3a of the chafer 3, compared to the width direction center side and width direction outer end side of the carcass ply 4. The feed pitch of the roller 31 is the movement distance of the roller 31 in the axial direction of the molding drum 10, i.e., in the width direction of the carcass ply 4, when the molding drum 10 rotates once.

The roller 31 is set to a width W1, for example, 16 mm. The feed pitch of the roller 31 is set to, for example, 9 mm at the center of the width of the carcass ply 4 when the roller 31 is moved at a moving speed V1, 3 mm in a predetermined range of the width of the carcass ply 4 when the roller 31 is moved at a moving speed V2, and 9 mm at the outer end of the width of the carcass ply 4 when the roller 31 is moved at a moving speed V3.

The rollers 31 are pressed against the radially inward side of the molding drum 10 by the moving mechanism 33 at a predetermined pressure, for example, 0.3 MPa. Each roller 31 is pressed against the molding drum 10 while rotating, and rotates at least one revolution in the tire circumferential direction relative to the carcass ply 4.

The manufacturing device 1 also includes a control device 50 that controls the operation of the drum drive device 11, the supply device 20, the pressing device 30, etc. The control device 50 controls the operation of the motor serving as the drum drive device 11, the movement mechanism 33 of the pressing device 30, etc. The control device 50 is configured with, for example, a microcomputer as its main component.

The control device 50 drives the molding drum 10 to rotate while sequentially supplying the inner liner 2, the chafers 3 on both sides, and the carcass ply 4 to the molding drum 10, and sequentially winds the inner liner 2, the chafers 3 on both sides, and the carcass ply 4 around the molding drum 10.

The control device 50 also presses the inner liner 2, both side chafers 3, and carcass ply 4, which are wound sequentially around the building drum 10, from the outer surface side with the roller 31, and moves the roller 31 from the widthwise inner side of the widthwise inner end 3a of the chafer 3 to the widthwise outer side of the widthwise outer end 4a of the carcass ply 4.

As described above, when manufacturing a pneumatic tire, the inner liner 2, the chafers 3 on both sides, and the carcass ply 4 are wound in sequence around the molding drum 10 in the manufacturing device 1 to mold the carcass band 5. The carcass ply 4 is pressed from the outer surface side by the roller 31 against the inner liner 2, the chafers 3 on both sides, and the carcass ply 4 that have been wound in sequence around the molding drum 10, while the roller 31 moves from the widthwise inner side of the widthwise inner end 3a of the chafer 3 to the widthwise outer side of the widthwise outer end 4a of the carcass ply 4 while rotating the molding drum 10.

In this embodiment, when the roller 31 is moved to the outside in the width direction of the carcass ply 4, the feed pitch of the roller 31 is made smaller in a predetermined width direction range of the carcass ply 4 including the inner end 3a of the chafer 3 compared to the width direction center side and width direction outer end side of the carcass ply 4.

After the carcass band 5 is molded, it is moved to and held on another molding drum, and then beads are attached to both sides of the carcass band 5 and folded back around the beads, and sidewall rubber is wrapped around it to mold a cylindrical green case. Meanwhile, tire components such as the belt and tread rubber are wound in sequence around yet another molding drum to mold a cylindrical tread band.

Then, after the tread band is transported radially outward from the green case, the green case is expanded radially outward into a toroidal shape and joined to the inner surface of the tread band, forming a green tire. The molded green tire is then vulcanized and molded by a vulcanization molding device to produce a pneumatic tire.

In this embodiment, when the roller 31 is moved to the outside in the width direction of the carcass ply 4, the rotation speed of the molding drum 10 is kept constant and the movement speed of the roller 31 is changed. However, by keeping the movement speeds V1, V2, and V3 of the roller 31 constant and changing the rotation speed R1 of the molding drum 10, the feed pitch of the roller 31 may be made smaller in a predetermined range in the width direction of the carcass ply 4, including the inner end 3a of the chafer 3, compared to the width direction center side and width direction outer end side of the carcass ply 4.

In addition, by changing the rotation speed of the molding drum 10 and the movement speed of the rollers, it is also possible to make the feed pitch of the rollers 31 smaller in a specified range of the width of the carcass ply 4, including the inner end 3a of the chafer 3, compared to the width center side and width outer end side of the carcass ply 4.

In this way, in this embodiment, when manufacturing a pneumatic tire, the roller 31 presses the inner liner 2, the chafers 3 on both sides, and the carcass ply 4, which are wound sequentially around the building drum 10, from the outer surface side, while moving the roller 31 from the center side of the width of the carcass ply 4 to the outer end of the width direction while rotating the building drum 10.

The feed pitch of the roller 31 is made smaller in a predetermined range in the width direction of the carcass ply 4, including the inner end 3a of the chafer 3, compared to the width direction center side and width direction outer end side of the carcass ply 4. Therefore, compared to when the feed pitch of the roller 31 is not made smaller, the roller 31 moves less, and the roller 31 easily deforms the carcass ply 4 radially along the inner liner 2 and chafer 3 near the step portion formed in the carcass ply 4 by the inner end 3a of the chafer 3.

As a result, when the roller 31 is moved from the widthwise center of the carcass ply 4 to the widthwise outer end thereof to move and discharge the air present between the inner liner 2 and the carcass ply 4 to the widthwise outer side of the carcass ply 4, the air present between the inner liner 2 and the carcass ply 4 can be easily moved widthwise outward from the widthwise inner end 3a of the chafer 3, and air accumulation near the inner end 3a of the chafer 3 between the inner liner 2 and the carcass ply 4 can be suppressed.

In addition, the feed pitch of the roller 31 is made smaller in a predetermined widthwise range of the carcass ply 4 including the inner end 3a of the chafer 3 compared to the widthwise center side and widthwise outer end side of the carcass ply 4. Therefore, compared to when the feed pitch of the roller 31 is made smaller even at the widthwise center side or widthwise outer end side of the carcass ply 4, the feed time of the roller 31 moving from the widthwise center side to the widthwise outer end side of the carcass ply 4 can be shortened, and production can be performed with good productivity.

This allows for efficient production while preventing air from accumulating near the inner end 3a of the chafer 3 between the inner liner 2 and the carcass ply 4.

The chafer 3 is a steel chafer. This effectively prevents air from accumulating near the inner end 3a of the chafer 3 between the inner liner 2 and the carcass ply 4 when the steel chafer 3 is placed between the inner liner 2 and the carcass ply 4. When a steel chafer, which is more likely to accumulate air than a nylon chafer, is placed, it effectively prevents air from accumulating near the inner end 3a of the chafer 3.

In this embodiment, when the roller 31 is moved from the widthwise center of the carcass ply 4 to the widthwise outer side of the widthwise outer end 4a of the carcass ply 4, the pressing force applied by the roller 31 to the carcass ply 4 by the moving mechanism 33 is set to a constant predetermined pressure, but it is also possible to increase the pressing force in a predetermined widthwise range of the carcass ply 4 including the inner end 3a of the chafer 3 compared to the widthwise center of the carcass ply 4.

The pressing force applied by the roller 31 to the carcass ply 4 is set to a first pressing force such as 0.2 MPa in the range from the widthwise center line L1 of the carcass ply 4 to the first predetermined position P1, a second pressing force higher than the first pressing force such as 0.3 MPa in the range from the first predetermined position P1 to the second predetermined position P2, and the first pressing force such as 0.2 MPa in the range from the second predetermined position P2 to the third predetermined position P3. The pressing force applied by the roller 31 to the carcass ply 4 may be set to a second pressing force such as 0.3 MPa in the range from the second predetermined position P2 to the third predetermined position P3.

In this way, the pressing force of the roller 31 can be increased in a predetermined widthwise range of the carcass ply 4, including the inner end 3a of the chafer 3, compared to the widthwise center of the carcass ply 4. In this case, the roller 31 deforms the carcass ply 4 more radially along the inner liner 2 and the chafer 3 near the step formed in the carcass ply 4 by the inner end 3a of the chafer 3, and air accumulation near the inner end 3a of the chafer 3 can be further suppressed.

Next, we will explain the manufacture of a pneumatic tire according to the second embodiment of the present invention.

The manufacture of the pneumatic tire according to the second embodiment is similar to the manufacture of the pneumatic tire according to the first embodiment, except for the placement of a joining tape covering the widthwise inner end 3a of the chafer 3, which is placed between the inner liner 2 and the carcass ply 4, so a description of the similar configuration will be omitted.

Figure 6 is a cross-sectional view showing a tire component wound around a building drum according to the second embodiment of the present invention. Figure 6 shows a cross-section of the tire component corresponding to Figure 4. As shown in Figure 6, in the manufacture of a pneumatic tire according to the second embodiment, a joining tape 6 is placed between the inner liner 2 and the carcass ply 4 to join the chafers 3 on both sides to the carcass ply 4.

The splicing tapes 6 are each provided to cover the widthwise inner end 3a of the chafer 3. The splicing tapes 6 are formed so that the widthwise inner end 6a is located widthwise inward of the widthwise inner end 3a of the chafer 3, and the widthwise outer end 6b is located widthwise outward of the widthwise inner end 3a of the chafer 3 and widthwise inward of the widthwise outer end 4a of the carcass ply 4.

In this embodiment, the supply device 20 supplies the carcass ply 4 to the molding drum 10 with both sides of the splice tape 6 attached to the inner surface of the carcass ply 4, spaced apart in the width direction. In the manufacturing device 1, the inner liner 2, both sides of the chafers 3, and the carcass ply 4 with both sides of the splice tape 6 attached are sequentially wound around the molding drum 10.

Figure 7 is an explanatory diagram for explaining the roller pressing process. As shown in Figure 7, the rollers 31 of the pressing device 30 are each formed narrower than the widthwise inner ends 3a of the chafers 3 on both sides and narrower than the widthwise inner ends 6a of the splicing tapes 6 on both sides. Specifically, the rollers 31 are formed narrower than half the distance between the widthwise inner ends 6a of the splicing tapes 6 on both sides.

In this embodiment, the carcass ply 4, which includes the inner liner 2, the chafers 3 on both sides, and the splice tape 6 on both sides, is pressed from the outer surface side by the roller 31 while the forming drum 10 is rotated and moved from the widthwise inner side of the widthwise inner end 3a of the chafer 3 to the widthwise outer side of the widthwise outer end 4a of the carcass ply 4.

When the roller 31 is moved from the inner widthwise position to the outer widthwise position of the carcass ply 4, the roller 31 is moved at a moving speed V1 at the center of the widthwise direction of the carcass ply 4, at a moving speed V2 in a predetermined range of the widthwise direction of the carcass ply 4 including the inner end 3a of the chafer 3 between the center of the widthwise direction of the carcass ply 4 and the outer end of the widthwise direction, and at a moving speed V3 at the outer end of the widthwise direction of the carcass ply 4, while rotating the molding drum 10 at a constant rotational speed R1.

As shown in FIG. 6, the first predetermined position P1 that defines the range of the widthwise center side of the carcass ply is set inside the widthwise inner end 6a of the splicing tape 6, and the second predetermined position P2 that defines the range of the widthwise outer end side of the carcass ply is set outside the widthwise outer end 6b of the splicing tape 6.

In this embodiment, the movement speed of the roller 31 is also made slower in a predetermined widthwise range of the carcass ply 4, including the inner end 3a of the chafer 3, compared to the widthwise center side and widthwise outer end side of the carcass ply 4, and the movement speed V2 of the roller 31 is made slower than the movement speed V1 and movement speed V3 of the roller 31.

Since the molding drum 10 rotates at a constant rotational speed R1, the feed pitch of the roller 31 that moves the roller 31 in the width direction of the carcass ply 4 is made smaller in a predetermined width direction range of the carcass ply 4 including the inner end 3a of the chafer 3 than in the width direction center side and width direction outer end side of the carcass ply 4. In this embodiment, the feed pitch of the roller 31 is made smaller in a predetermined width direction range of the carcass ply 4 including the splice tape 6 than in the width direction center side and width direction outer end side of the carcass ply 4.

In this manner, in this embodiment, the roller 31 presses the inner liner 2, the chafers 3 on both sides, and the carcass ply 4, which are wound sequentially around the molding drum 10, from the outer surface side, while moving the roller 31 from the center side of the width of the carcass ply 4 to the outer end of the width direction while rotating the molding drum 10.

The feed pitch of the roller 31 is made smaller in a predetermined range in the width direction of the carcass ply 4, including the inner end 3a of the chafer 3, compared to the width direction center side and width direction outer end side of the carcass ply 4, so that air accumulation near the inner end 3a of the chafer 3 between the inner liner 2 and the carcass ply 4 can be suppressed, and manufacturing can be performed with good productivity.

In addition, a splice tape 6 is placed between the chafer 3 and the carcass ply 4 to cover the widthwise inner end 3a of the chafer 3, and the feed pitch of the roller 31 is made smaller in a predetermined widthwise range of the carcass ply 4 including the splice tape 6 than in the widthwise center side and widthwise outer end side of the carcass ply 4.

This allows the joining tape 6 to increase the joining strength between the chafer 3 and the carcass ply 4, and suppresses changes in strength due to the chafer 3 of the pneumatic tire at the inner end 3a of the chafer 3 that is placed between the inner liner 2 and the carcass ply 4. Even when the joining tape 6 is placed between the chafer 3 and the carcass ply 4, air accumulation near the inner end 3a of the chafer 3 between the inner liner 2 and the carcass ply 4 is suppressed, and the tire can be manufactured with good productivity.

In the embodiment described above, the inner liner 2 is formed so that the widthwise outer ends 2a on both sides are positioned widthwise outward from the widthwise outer ends 3b of the chafers 3 on both sides, but it may be formed so that it is positioned widthwise outward from the widthwise inner ends 3a of the chafers 3 on both sides and widthwise inward from the widthwise outer ends 3b of the chafers 3 on both sides.

Next, we will explain the manufacture of a pneumatic tire according to the third embodiment of the present invention.

The inner liner 2 in the above-described embodiment is formed by integrally forming the inner liner and the rubber chafer, but in the third embodiment, the inner liner 2 and the rubber chafer 7 are formed separately. The manufacture of the pneumatic tire in the third embodiment is similar to the manufacture of the pneumatic tire in the second embodiment, except that the inner liner 2 and the rubber chafer 7 are formed separately, so a description of the similar configuration will be omitted.

Figure 8 is a cross-sectional view showing a tire component wound around a building drum according to the third embodiment of the present invention. In Figure 8, the tire component wound around the building drum according to the third embodiment is shown in a cross section corresponding to Figure 4. As shown in Figure 8, in the manufacture of a pneumatic tire according to the third embodiment, separate chafers 7 on both sides, specifically rubber chafers 7, are placed between the inner liner 2 and the chafers 3 on both sides, specifically steel chafers 3.

The rubber chafers 7 on both sides are formed so that at least the widthwise inner end 7a is located widthwise inward of the widthwise outer end 2a of the inner liner 2. Also, the rubber chafers 7 are formed so that the widthwise outer end 7b is located widthwise outward of the widthwise outer end 3b of the steel chafer 3.

In this embodiment, the supply device 20 sequentially supplies the inner liner 2, the rubber chafers 7 on both sides, the steel chafers 3 on both sides, and the carcass ply 4 to which the splicing tape 6 on both sides is attached to the molding drum 10.

In the manufacturing device 1, the carcass ply 4, which has the inner liner 2, rubber chafers 7 on both sides, steel chafers 3 on both sides, and splicing tape 6 on both sides, wound sequentially around the molding drum 10, is pressed from the outer side by the roller 31, while the roller 31 moves from the widthwise inner side of the widthwise inner end 3a of the chafer 3 to the widthwise outer side of the widthwise outer end 4a of the carcass ply 4 while rotating the molding drum 10.

While rotating the molding drum 10 at a constant rotation speed R1, the roller 31 is moved at a moving speed V1 at the center side of the width direction of the carcass ply 4, at a moving speed V2 in a predetermined range of the width direction of the carcass ply 4 including the inner end 3a of the chafer 3 between the center side of the width direction of the carcass ply 4 and the outer end side of the width direction, and at a moving speed V3 at the outer end side of the width direction of the carcass ply 4.

In this embodiment, the movement speed of the roller 31 is also made smaller in a predetermined widthwise range of the carcass ply 4 including the inner end 3a of the chafer 3 than the widthwise center side and widthwise outer end side of the carcass ply 4, and the movement speed V2 of the roller 31 is made smaller than the movement speeds V1 and V3 of the roller 31. The feed pitch of the roller 31 that moves the roller 31 in the widthwise direction of the carcass ply 4 is made smaller in a predetermined widthwise range of the carcass ply 4 including the inner end 3a of the chafer 3 than the widthwise center side and widthwise outer end side of the carcass ply 4.

In this embodiment, a splice tape 6 is placed between the inner liner 2 and the carcass ply 4 to cover the widthwise inner end 3a of the chafer 3, but it is also possible not to place the splice tape covering the widthwise inner end 3a of the chafer 3 between the inner liner 2 and the carcass ply 4.

In this manner, in this embodiment, the roller 31 presses the inner liner 2, the chafers 3 on both sides, and the carcass ply 4, which are wound sequentially around the molding drum 10, from the outer surface side, while moving the roller 31 from the center side of the width of the carcass ply 4 to the outer end of the width direction while rotating the molding drum 10.

The feed pitch of the roller 31 is made smaller in a predetermined range in the width direction of the carcass ply 4, including the inner end 3a of the chafer 3, compared to the width direction center side and width direction outer end side of the carcass ply 4, so that air accumulation near the inner end 3a of the chafer 3 between the inner liner 2 and the carcass ply 4 can be suppressed, and manufacturing can be performed with good productivity.

Next, we will explain the manufacture of a pneumatic tire according to the fourth embodiment of the present invention.

The manufacture of the pneumatic tire according to the fourth embodiment is similar to the manufacture of the pneumatic tire according to the first embodiment, except that the carcass ply 4 is pressed from the outer side by another roller formed with a lower hardness than the roller 31 before the roller 31 is moved from the widthwise center of the carcass ply 4 to the widthwise outer end while rotating the molding drum 10, and therefore a description of the similar configuration is omitted.

Figure 9 is a schematic side view of a pneumatic tire manufacturing apparatus according to a fourth embodiment of the present invention. Figure 10 is a schematic front view of a pneumatic tire manufacturing apparatus. As shown in Figures 9 and 10, the manufacturing apparatus 1' according to the fourth embodiment includes a building drum 10, a drum drive device 11, and a supply device 20, similar to the manufacturing apparatus 1 according to the first embodiment.

As shown in FIG. 4, the supply device 20 sequentially supplies the inner liner 2, the chafers 3 on both sides spaced apart in the width direction, and the carcass ply 4 to the molding drum 10. In the manufacturing device 1', the carcass ply 4 is wound cylindrically around the inner liner 2 and the chafers 3 on both sides of the molding drum 10.

The manufacturing apparatus 1' also includes a first pressing device 40 and a second pressing device 30 that press the inner liner 2, the chafers 3 on both sides, and the carcass ply 4 that are wound around the molding drum 10 in sequence from the outer surface side. The second pressing device 30 is configured similarly to the pressing device 30 of the manufacturing apparatus 1, except that the roller 31 is a second roller 31. The control device 50 of the manufacturing apparatus 1' controls the operation of the motor as the drum drive device 11, the movement mechanism of the first pressing device 40, and the movement mechanism 33 of the second pressing device 30, etc.

As shown in Figures 9 and 10, the first pressing device 40 includes a cylindrical first roller 41, a shaft 42 inserted through and fixed to the first roller 41, and a moving mechanism 43 that moves the shaft 42 in the radial direction of the molding drum 10. The moving mechanism 43 includes a support portion 44 that rotatably supports the shaft 42, and is configured to be able to move the support portion 44 in the radial direction of the molding drum 10 to move the first roller 41 in the radial direction of the molding drum 10. As the moving mechanism 43, for example, a pneumatic cylinder is used.

The first roller 41 is configured to be movable in the radial direction of the molding drum 10 between a radially outer position shown by a solid line in FIG. 9 and a radially inner position shown by a two-dot chain line in FIG. 9 by a moving mechanism 43. The first roller 41 is configured to press the carcass ply 4 wound around the molding drum 10 from the outer surface side at the radially inner position.

The first roller 41 is formed with a hardness of 35 HDA or more and 45 HDA or less. If the hardness of the first roller 41 is less than 35 HDA, the first roller 41 is less likely to press against the carcass ply 4, and the air present between the inner liner 2 and the carcass ply 4 is less likely to move widthwise outward from the widthwise inner end 3a of the chafer 3. In addition, deformation such as wrinkles and damage to the first roller 41 are more likely to occur. On the other hand, if the hardness of the first roller 41 is greater than 45 HDA, the first roller 41 is less likely to bounce off the widthwise inner end 3a of the chafer 3 and press along the widthwise inner end 3a of the chafer 3, and the air present between the inner liner 2 and the carcass ply 4 is less likely to move widthwise outward from the widthwise inner end 3a of the chafer 3.

The hardness is the hardness (HDA) measured based on JIS K7311 using a type A durometer specified in JIS K7215. In this embodiment, the first roller 41 is formed to have a lower hardness than the second roller 31 of the second pressing device 30. The first roller 41 is formed from a sponge using, for example, urethane foam resin. The first roller 41 can have an outer diameter of 110 to 120 mm and a width of 380 to 450 mm, for example.

Figure 11 is an explanatory diagram for explaining the pressing process of the first roller. As shown in Figure 11, the first roller 41 of the first pressing device 40 is formed wider than the widthwise inner ends 3a of the chafers 3 on both sides and narrower than the widthwise outer ends 4a of the carcass ply 4 on both sides.

The first pressing device 40 moves the first roller 41 radially inward of the molding drum 10 against the inner liner 2, the chafers 3 on both sides, and the carcass ply 4 that are wound around the molding drum 10 in sequence, and presses the carcass ply 4 from the outer surface side with the first roller 41 for a predetermined time, such as 5 seconds, at a predetermined pressure, such as 0.3 MPa. The first roller 41 is pressed while rotating the molding drum 10, and rotates at least one revolution in the tire circumferential direction against the carcass ply 4.

The second pressing device 30 presses the carcass ply 4 with the first roller 41 of the first pressing device 40, and after the first roller 41 is moved to a radially outer position, moves a pair of second rollers 31 to the radially inner side of the molding drum 10 at the widthwise inner position, and presses the carcass ply 4 from the outer surface side with the second rollers 31.

Then, while pressing the carcass ply 4 from the outer surface side with the second roller 31, the second roller 31 is moved from the widthwise center side of the carcass ply 4, which is inside the widthwise inner end 3a of the chafer 3, to the widthwise outer side of the widthwise outer end 4a of the carcass ply 4 while rotating the molding drum 10.

In this embodiment, too, when the second roller 31 is moved from the inner position in the width direction to the outer side in the width direction of the carcass ply 4, the feed pitch of the second roller 31 that moves the second roller 31 in the width direction of the carcass ply 4 is made smaller in a predetermined width direction range of the carcass ply 4 including the inner end 3a of the chafer 3 compared to the width direction center side and width direction outer end side of the carcass ply 4.

In this embodiment, as in the second embodiment described above, a joining tape 6 may be placed between the steel chafer 3 and the carcass ply 4 to cover the inner end 3a of the chafer 3 in the width direction.

In this manner, in this embodiment, the second roller 31 presses the inner liner 2, the chafers 3 on both sides, and the carcass ply 4, which are wound sequentially around the molding drum 10, from the outer surface side, while moving the second roller 31 from the center side of the width of the carcass ply 4 to the outer end of the width direction while rotating the molding drum 10.

The feed pitch of the second roller 31 is made smaller in a predetermined widthwise range of the carcass ply 4, including the inner end 3a of the chafer 3, compared to the widthwise center side and widthwise outer end side of the carcass ply 4, so that air accumulation near the inner end 3a of the chafer 3 between the inner liner 2 and the carcass ply 4 is suppressed, and production can be performed with good productivity.

In this embodiment, the carcass ply 4 is pressed from the outer surface side by the first roller 41 formed to be wider than the widthwise inner ends 3a of the chafers 3 on both sides and narrower than the widthwise outer ends 4a of the carcass ply 4 on both sides, and then the second roller 31 is moved from the widthwise center side of the carcass ply 4 to the widthwise outer end 4a while rotating the molding drum 10 while pressing the carcass ply 4 from the outer surface side by the second roller 31. The second roller 31 has a smaller feed pitch in a predetermined range in the width direction of the carcass ply 4 including the inner end 3a of the chafer 3 compared to the widthwise center side and widthwise outer end side of the carcass ply 4, and the first roller 41 is formed to have a lower hardness than the second roller 31.

As a result, the first roller 41 is formed with a lower hardness than the second roller 31, so that the first roller 41 easily deforms the carcass ply 4 in the radial direction along the inner liner 2 and the chafer 3, and the first roller 41 easily moves the air present between the inner liner 2 and the carcass ply 4 outward in the width direction from the inner end 3a of the chafer 3. Since the first roller 41 is formed narrower than the outer end 4a of the carcass ply 4 on both sides, the first roller 41 easily moves the air present between the inner liner 2 and the carcass ply 4 outward in the width direction from the inner end 3a of the chafer 3, compared to when the first roller 41 is formed wider than the outer end 4a of the carcass ply 4 on both sides. Furthermore, the second roller 31 can move the air outward in the width direction from the outer end 4a of the carcass ply 4 and discharge it, which further suppresses the accumulation of air between the inner liner 2 and the carcass ply 4 near the inner end 3a of the chafer 3.

The present invention is not limited to the illustrated embodiments, and various improvements and design changes are possible without departing from the spirit of the present invention.

1, 1' Manufacturing device 2 Inner liner 3 Steel chafer 4 Carcass ply 6 Splicing tape 10 Forming drum 31 Roller

Claims (6)

An inner liner, chafers on both sides arranged on the inner liner at a distance in the width direction, and a carcass ply formed wider than the inner ends of the chafers on both sides in the width direction and arranged on the inner liner and the chafers on both sides are sequentially wound around a building drum;
While pressing the carcass ply from the outer surface side with a roller, the roller is moved from the width direction center side of the carcass ply to the width direction outer end side while rotating the molding drum;
A method for manufacturing a pneumatic tire, comprising the steps of: making the feed pitch of the roller for moving the roller smaller in a predetermined widthwise range of the carcass ply including the inner end of the chafer than in the widthwise center side and the widthwise outer end side of the carcass ply. The method for manufacturing a pneumatic tire according to claim 1, wherein the chafer is a steel chafer. A joining tape is disposed between the chafer and the carcass ply to cover an inner end portion of the chafer in a width direction,
3. The method for manufacturing a pneumatic tire according to claim 1, wherein a feed pitch of the roller is made smaller in a predetermined widthwise range of the carcass ply including the joining tape than in a widthwise center side and a widthwise outer end side of the carcass ply. The pressing force applied by the roller to the carcass ply is increased in a predetermined range in the width direction of the carcass ply including the inner end portion of the chafer, compared to a central side in the width direction of the carcass ply.
A method for manufacturing a pneumatic tire according to any one of claims 1 to 3. The carcass ply is pressed from the outer surface side by a first roller formed to be wider than the inner ends of the chafers in the width direction and narrower than the outer ends of the carcass ply in the width direction on both sides,
After the carcass ply is pressed by the first roller, the second roller is moved from the width direction center side of the carcass ply to the width direction outer end side while pressing the carcass ply from the outer surface side by the second roller while rotating the molding drum;
A feed pitch of the second roller for moving the second roller is made smaller in a predetermined range in the width direction of the carcass ply including the inner end of the chafer than in a center side in the width direction and an outer end side in the width direction of the carcass ply;
The method for manufacturing a pneumatic tire according to claim 1 , wherein the first roller is formed to have a lower hardness than the second roller. a molding drum on which an inner liner, chafers on both sides spaced apart from each other in the width direction are sequentially wound, and a carcass ply formed wider than the inner ends of the chafers in the width direction and disposed on the inner liner and the chafers on both sides;
a roller formed narrower than the inner end of the chafer on each side in the width direction,
The inner liner, the chafers on both sides, and the carcass ply, which are sequentially wound around the molding drum, are pressed from the outer surface side by the roller, and the roller is moved from the width direction center side of the carcass ply to the width direction outer end side while rotating the molding drum;
A pneumatic tire manufacturing apparatus, comprising: a roller feed pitch for moving the roller being made smaller in a predetermined widthwise range of the carcass ply including the inner end of the chafer than in a widthwise center side and a widthwise outer end side of the carcass ply.

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