JP6030623B2 - Pneumatic tire - Google Patents

Description

  The present invention relates to a pneumatic tire.

  Usually, in order to reinforce the belt, the tire is provided with a band on the radially outer side. The band contains a cord. The cord extends substantially in the circumferential direction and is wound spirally. The band has a so-called jointless structure. The band restrains the belt. Thereby, lifting of the belt is suppressed.

  The band is formed by winding a ribbon including a plurality of parallel cords spirally in the circumferential direction. FIG. 7 shows the structure of a conventional band 1. In FIG. 7, the vertical direction is the circumferential direction, the horizontal direction is the axial direction, and the vertical direction of the paper is the radial direction. In this band 1, one ribbon 2 is spirally wound from the vicinity of one outer end of the tire toward the other outer end of the tire in the axial direction. In this method, it takes time to wind the ribbon 2 when manufacturing the tire. This tire is inferior in productivity.

  From the viewpoint of improving productivity, the band may be composed of two ribbons. FIG. 8 shows this band 3. In FIG. 8, the alternate long and short dash line CL represents the equator plane of the tire. The band 3 is formed using the first ribbon 4 and the second ribbon 5. The first ribbon 4 is wound spirally from the equatorial plane CL toward one axial outer side of the tire. The second ribbon 5 is wound spirally from the equatorial plane CL toward the other axially outer side of the tire. Since these two ribbons are wound simultaneously, the productivity of the tire is improved.

  As shown in FIG. 8, the first ribbon 4 and the second ribbon 5 are inclined in opposite directions with respect to the equator plane CL. For this reason, a gap 6 between the first ribbon 4 and the second ribbon 5 is formed on the equator plane CL. On the equator plane CL of the tire, a portion with the gap 6 and a portion without the gap 6 are mixed. In other words, unevenness due to the gap 6 exists in the equator portion of the tire. This tire is inferior in uniformity.

  Japanese Unexamined Patent Application Publication No. 2012-25308 discloses a tire that improves tire productivity and suppresses deterioration of uniformity. The tire band is composed of two ribbons. In this band, the winding start position of the first ribbon and the winding start position of the second ribbon are shifted in the circumferential direction. Thereby, the clearance gap produced between a 1st ribbon and a 2nd ribbon is disperse | distributed to the circumferential direction. Thereby, the improvement of uniformity is achieved.

JP2012-25308A

  There is a need for a tire with improved uniformity while improving tire productivity. The contact pressure is high on the tire equator. The gap between the ribbons on the tire equator has a great influence on the tire uniformity. In the tire disclosed in Japanese Patent Application Laid-Open No. 2012-25308, the gap 6 of the ribbon is located on the equator plane CL of the tire. In this tire, the uniformity is not sufficiently improved.

  An object of the present invention is to provide a tire excellent in uniformity and productivity.

  The tire according to the present invention includes a tread whose outer surface forms a tread surface, and a band positioned on the inner side in the radial direction of the tread. The band is configured by winding a first ribbon, a second ribbon, and a third ribbon. Each of the first ribbon, the second ribbon, and the third ribbon includes a cord extending in the length direction. In the tire, when the region on the outer side in the axial direction of the equator plane is the first region and the region on the outer side in the axial direction of the equator surface is the second region, the first ribbon Is wound spirally in a substantially circumferential direction from the inner side to the outer side in the axial direction. In the second region, the second ribbon is spirally wound in a substantially circumferential direction from the inner side to the outer side in the axial direction. On the equator plane, the third ribbon is wound just in the circumferential direction.

  Preferably, in the axial direction, when the minimum distance between the first ribbon and the second ribbon is Wb and the width of the third ribbon is Wa, the ratio of the width Wa to the distance Wb (Wa / Wb) Is 0.7 or more and 1.0 or less.

  The method for manufacturing a tire according to the present invention is for a tire including a tread whose outer surface forms a tread surface and a band positioned on the inner side in the radial direction of the tread. This method uses a former having a rotatable cylindrical drum, a first head for feeding a first ribbon, a second head for feeding a second ribbon, and a third head for feeding a third ribbon. The method includes a step of winding a first ribbon, a second ribbon, and a third ribbon in the drum to obtain a band. The step of obtaining the band when the first outer region in the axial direction of the equator plane in the tire is the first region and the second outer region in the axial direction of the equator surface is the second region. The tip of the first ribbon sent out from one head is arranged on the drum, and the drum is rotated and the first head is moved from the inner side to the outer side in the axial direction. A first step in which the first ribbon is spirally wound, and a tip of the second ribbon fed from the second head is disposed on the drum, and the drum is rotated and By moving the second head from the inner side toward the end in the axial direction, the second ribbon is spirally wound in the second region, and the second head is fed from the third head. Third above Tip Bonn is disposed on the drum, by rotating the drum, and a third step of the third ribbon is I wound exactly in the circumferential direction on the equatorial plane of the tire. The first step and the second step are performed simultaneously.

  Preferably, the third step is simultaneously performed while the first step and the second step are being performed.

  In the tire band according to the present invention, the third ribbon is wound just in the circumferential direction on the equator plane. There is no gap between the ribbons on the equator of the tire. This tire is excellent in uniformity. In this band, in one axially outer region of the equator plane, the first ribbon is spirally wound in a substantially circumferential direction from the axially inner side to the outer side. In the other axially outer region of the equator plane, the second ribbon is spirally wound in a substantially circumferential direction from the axially inner side to the outer side. The first ribbon and the second ribbon can be wound at the same time when the tire is manufactured. This tire is excellent in productivity.

FIG. 1 is a cross-sectional view showing a part of a pneumatic tire according to an embodiment of the present invention. FIG. 2 is a schematic diagram showing the configuration of the tire band of FIG. 1. FIG. 3 is a cross-sectional perspective view showing a part of the ribbon used for forming the band shown in FIG. FIG. 4 is a plan view showing a state of starting the formation of the band shown in FIG. FIG. 5 is a side view showing a state of starting the formation of the band shown in FIG. FIG. 6 is a plan view showing a state during the formation of the band shown in FIG. FIG. 7 is a schematic view showing a configuration of a conventional tire band. FIG. 8 is a schematic view showing the configuration of another conventional tire band.

  Hereinafter, the present invention will be described in detail based on preferred embodiments with appropriate reference to the drawings.

  The tire 7 shown in FIG. 1 includes a tread 8, a sidewall 9, a clinch 10, a bead 11, a carcass 12, a belt 14, a band 16, an edge band 18, an inner liner 20, and a chafer 22. The tire 7 is a tubeless type. The tire 7 is attached to a passenger car.

  In FIG. 1, the vertical direction is the radial direction, the horizontal direction is the axial direction, and the direction perpendicular to the paper surface is the circumferential direction. The tire 7 has a substantially bilaterally symmetric shape with the one-dot chain line CL in FIG. 1 as the center. This alternate long and short dash line CL represents the equator plane of the tire 7. Reference sign A1 represents the first region. The first region A1 is a region located on the outer side in the one axial direction of the equator plane CL of the tire 7. Reference symbol A2 represents the second region. The second region A2 is a region located on the other axially outer side of the equator plane CL of the tire 7.

  The tread 8 is made of a crosslinked rubber. The tread 8 has a shape protruding outward in the radial direction. The tread 8 includes a tread surface 24. The tread surface 24 is in contact with the road surface. A groove 25 is carved in the tread surface 24. The groove 25 forms a tread pattern. Note that the groove 25 may not be cut in the tread surface 24.

  The sidewall 9 extends substantially inward in the radial direction from the end of the tread 8. The sidewall 9 is made of a crosslinked rubber. The side wall 9 absorbs an impact from the road surface by bending. Furthermore, the sidewall 9 prevents the carcass 12 from being damaged.

  The clinch 10 is located substantially inside the sidewall 9 in the radial direction. The clinch 10 is located outside the beads 11 and the carcass 12 in the axial direction. The clinch 10 is made of a crosslinked rubber having excellent wear resistance. The clinch 10 contacts the rim flange.

  The bead 11 is located inside the clinch 10 in the axial direction. The bead 11 includes a core 26 and an apex 28 that extends radially outward from the core 26. The core 26 has a ring shape and includes a wound non-stretchable wire. A typical material for the wire is steel. The apex 28 is tapered outward in the radial direction. The apex 28 is made of a highly hard crosslinked rubber.

  The carcass 12 includes a carcass ply 30. The carcass ply 30 is bridged between the beads 11 on both sides, and extends along the inside of the tread 8 and the sidewall 9. The carcass ply 30 is folded around the core 26 from the inner side to the outer side in the axial direction.

  Although not shown, the carcass ply 30 includes a large number of cords arranged in parallel and a topping rubber. The absolute value of the angle formed by each cord with respect to the equator plane CL is usually 70 ° to 90 °. In other words, the carcass 12 has a radial structure. The cord is usually made of organic fibers. Examples of preferable organic fibers include polyester fibers, nylon fibers, rayon fibers, polyethylene naphthalate fibers, and aramid fibers. A carcass 12 having a bias structure may be employed.

  The belt 14 is located inside the band 16 in the radial direction. The belt 14 is located on the radially outer side of the carcass 12. The belt 14 is laminated with the carcass 12. The belt 14 reinforces the carcass 12. The belt 14 includes an inner layer 14a and an outer layer 14b. Although not shown, each of the inner layer 14a and the outer layer 14b is composed of a large number of cords arranged in parallel and a topping rubber. Each cord is inclined with respect to the equatorial plane CL. The absolute value of the tilt angle is not less than 10 ° and not more than 35 °. The cord inclination direction of the inner layer 14a is opposite to the cord inclination direction of the outer layer 14b. A preferred material for the cord is steel. An organic fiber may be used for the cord.

  The band 16 is located on the inner side in the radial direction of the tread 8. The band 16 covers the belt 14. This band 16 is a full band 16. FIG. 2 is a schematic diagram showing the configuration of the band 16. In FIG. 2, the vertical direction is the circumferential direction, the horizontal direction is the axial direction, and the vertical direction of the paper is the radial direction. Also in this figure, the equatorial plane CL, the first region A1, and the second region A2 are shown together.

  As shown in FIG. 2, the band 16 includes a first ribbon 32, a second ribbon 34, and a third ribbon 36. The band 16 is configured by winding a first ribbon 32, a second ribbon 34, and a third ribbon 36 on the outer side in the radial direction of the belt 14. The first ribbon 32 is spirally wound in a substantially circumferential direction from the inner side in the axial direction toward the outer side in the first region A1. The second ribbon 34 is spirally wound in a substantially circumferential direction from the inner side in the axial direction toward the outer side in the second region A2. The third ribbon 36 is wound in the circumferential direction just on the equator plane CL.

  FIG. 3 shows a cross-sectional perspective view of the first ribbon 32. Each of the first ribbon 32, the second ribbon 34, and the third ribbon 36 includes a plurality of cords 38 and a topping rubber 40 arranged in parallel. Each cord 38 of the first ribbon 32 extends in the length direction of the first ribbon 32. As illustrated, in the tire 7, the first ribbon 32 includes ten cords 38. The number of cords 38 included in the first ribbon 32 and the width of the ribbon are appropriately determined in consideration of workability and the like. The second ribbon 34 has the same structure as the first ribbon 32. The third ribbon 36 has the same structure as the first ribbon 32 and the second ribbon 34. The structure of the third ribbon 36 may be different from that of the first ribbon 32 and the second ribbon 34. For example, the third ribbon 36 may include more than ten cords 38.

  The cords 38 of the first ribbon 32, the second ribbon 34, and the third ribbon 36 are usually made of organic fibers. Examples of preferable organic fibers include nylon fibers, polyester fibers, rayon fibers, polyethylene naphthalate fibers, and aramid fibers.

  As described above, in the band 16, the first ribbon 32 and the second ribbon 34 including the cord 38 are wound in the substantially circumferential direction. A third ribbon 36 having a cord 38 is wound in the circumferential direction. Therefore, in this band 16, the cord 38 extends substantially in the circumferential direction. The angle of the cord 38 with respect to the circumferential direction is 5 ° or less, and further 2 ° or less. The band 16 has a so-called jointless structure. Since the belt 14 is restrained by the cord 38, the lifting of the belt 14 is suppressed.

  The edge band 18 is located outside the band 16 in the radial direction and in the vicinity of the end of the band 16. Although not shown, the edge band 18 is made of a cord and a topping rubber. The cord is wound in a spiral. The edge band 18 has a so-called jointless structure. The cord extends substantially in the circumferential direction. The angle of the cord with respect to the circumferential direction is 5 ° or less, and further 2 ° or less. Since the end of the belt 14 is restrained by this cord, the lifting of the belt 14 is suppressed. The cord is made of organic fiber. Examples of preferable organic fibers include nylon fibers, polyester fibers, rayon fibers, polyethylene naphthalate fibers, and aramid fibers.

  The inner liner 20 is located inside the carcass 12. The inner liner 20 is joined to the inner surface of the carcass 12. The inner liner 20 is made of a crosslinked rubber. The inner liner 20 is made of rubber having excellent air shielding properties. A typical base rubber of the inner liner 20 is butyl rubber or halogenated butyl rubber. The inner liner 20 holds the internal pressure of the tire 7.

  The chafer 22 is located in the vicinity of the bead 11. When the tire 7 is incorporated into the rim, the chafer 22 comes into contact with the rim. By this contact, the vicinity of the bead 11 is protected. The chafer 22 is made of cloth and rubber impregnated in the cloth. The chafer 22 may be configured integrally with the clinch 10.

  Below, the manufacturing method of this tire 7 is demonstrated.

  First, the plurality of cords 38 are extruded together with the topping rubber 40, and the first ribbon 32, the second ribbon 34, and the third ribbon 36 are obtained. These ribbons are supplied to a former (not shown) together with sheets for constituting the inner liner 20, the carcass ply 30 and the belt 14.

  The former includes a cylindrical drum. The drum is rotatable. By rotating the drum, a sheet for forming the inner liner 20 is wound around the drum. Thereby, the inner liner 20 is obtained. A sheet of the carcass ply 30 is wound thereon. Thereby, the cylindrical carcass ply 30 is obtained. A first sheet is wound around a cylindrical carcass ply 30 to form an inner layer 14 a that forms part of the belt 14. A second sheet is wound around the inner layer 14 a to form an outer layer 14 b that forms another part of the belt 14. Thereby, the belt 14 is obtained. The first ribbon 32, the second ribbon 34, and the third ribbon 36 are wound on the belt 14 to form the band 16.

  FIG. 4 is a plan view showing a state at the start of the formation of the band 16. In FIG. 4, the vertical direction is the circumferential direction, the horizontal direction is the axial direction, and the vertical direction of the paper is the radial direction. The equator plane CL, the first region A1, and the second region A2 of the tire 7 formed on the drum 42 are shown together. FIG. 5 is a side view showing a state at the start of the formation of the band 16. As described above, the inner liner 20, the carcass 12, and the belt 14 are formed around the drum 42 at the start of the formation of the band 16. In FIGS. 4 and 5, these are omitted.

  As shown in FIG. 5, the former further includes a first head 44, a second head 46, and a third head 48. The first head 44 feeds the first ribbon 32 and is movable in the axial direction. The second head 46 feeds the second ribbon 34 and is movable in the axial direction. The third head 48 feeds the third ribbon 36 and is movable in the axial direction. The third head 48 may not be movable in the axial direction. In this former, the first head 44, the second head 46, and the third head 48 can each move independently.

  In forming the band 16, first, the leading end of the first ribbon 32 fed out from the first head 44 is disposed on the drum 42. The leading end of the first ribbon 32 is disposed on the belt 14 formed on the drum 42 in the first region A1. The tip of the second ribbon 34 fed out from the second head 46 is disposed on the drum 42. The tip of the second ribbon 34 is disposed on the belt 14 formed on the drum 42 in the second region A2. The third ribbon 36 is not disposed on the drum 42 at this stage. 4 and 5 show a state in which the leading end of the first ribbon 32 and the leading end of the second ribbon 34 are arranged on the drum 42.

  Next, rotation of the drum 42 is started. The drum 42 rotates in the direction of arrow Z in FIG. As the drum 42 starts to rotate, the first head 44 is moved in the direction of arrow X in FIG. The first head 44 is moved from the inner side toward the outer side in the axial direction. Since the drum 42 is rotated and the first head 44 is moved, the first ribbon 32 is spirally wound. The first ribbon 32 is spirally wound in a substantially circumferential direction from the inner side to the outer side in the first region A1.

  As the drum 42 starts rotating, the second head 46 is moved in the direction of arrow Y in FIG. The second head 46 is moved from the inner side to the outer side in the axial direction. Since the drum 42 is rotated and the second head 46 is moved, the second ribbon 34 is wound spirally. The second ribbon 34 is spirally wound in a substantially circumferential direction from the inner side in the axial direction toward the outer side in the second region A2.

  FIG. 6 shows a state where the first ribbon 32 and the second ribbon 34 are being wound. While the first ribbon 32 and the second ribbon 34 are being wound, the tip of the third ribbon 36 fed from the third head 48 is disposed on the drum 42. The tip of the third ribbon 36 is disposed on the belt 14 formed on the drum 42 on the equator plane CL. FIG. 6 shows a state in which the tip of the third ribbon 36 is disposed on the drum 42.

  The drum 42 continues to rotate. The third head 48 sends out the third tape without moving. For this reason, the third tape is wound just in the circumferential direction on the equator plane CL. The first ribbon 32 is continuously wound spirally in the first region A1. The second ribbon 34 is continuously wound spirally in the second region A2.

  When the first ribbon 32 reaches the outer end of the belt 14, the winding of the first ribbon 32 is finished. When the second ribbon 34 reaches the other outer end of the belt 14, the winding of the second ribbon 34 is finished. The third ribbon 36 is wound just once. In this way, a band 16 covering the belt 14 is obtained. A band 16 having the structure shown in FIG. 3 is obtained.

  As described above, in the formation of the band 16, the tip of the first ribbon 32 is disposed on the drum 42, and the first head 44 is moved along with the rotation of the drum 42. In Step 1, the first ribbon 32 is spirally wound (referred to as the first step), and the tip of the second ribbon 34 is disposed on the drum 42 so that the second head 46 is moved along with the rotation of the drum 42. By moving the second ribbon A, the step of winding the second ribbon 34 spirally (referred to as a second step) is performed at the same time.

  Further, in the formation of the band 16, the tip of the third ribbon 36 is disposed on the drum 42 while the first step and the second step are being performed, and the drum 42 is rotated. A process (referred to as a third process) in which the third ribbon 36 is wound in the circumferential direction on the CL is started. The third step is performed while the first step and the second step are being performed. The first step is performed in parallel with the second step and the third step. The third step may be started simultaneously with the first step and the second step. The third step may be performed after the first step and the second step. The third step may be performed before the first step and the second step.

  After forming the band 16, the edge band 18 is wound on the band 16. Members such as the tread 8 are further combined to obtain a low cover (also referred to as an uncrosslinked tire 7).

  The raw cover is put into a mold (not shown). As a result, the outer surface of the raw cover comes into contact with the cavity surface of the mold. The inner surface of the raw cover contacts the bladder or the core. The raw cover is pressurized and heated in the mold. The rubber composition of the raw cover flows by pressurization and heating. The rubber causes a crosslinking reaction by heating, and the tire 7 is obtained.

  Hereinafter, the function and effect of the present invention will be described.

  In the band 16 of the tire 7 according to the present invention, the third ribbon 36 is wound in the circumferential direction on the equator plane CL. On the equator plane CL of the tire 7, there is no gap between the ribbons. This improves the uniformity of the tire 7. The tire 7 is excellent in uniformity.

  In the band 16, in the first region, the first ribbon 32 is spirally wound in a substantially circumferential direction from the inner side to the outer side in the axial direction. In the second region, the second ribbon 34 is spirally wound in the circumferential direction from the inner side to the outer side in the axial direction. In manufacturing the tire 7, the first process in which the first ribbon 32 is wound and the second process in which the second ribbon 34 is wound are performed simultaneously. The tire 7 is excellent in productivity. The tire 7 manufacturing method achieves excellent productivity.

  As described above, in this manufacturing method, it is preferable that the third process in which the third ribbon 36 is wound is performed while the first process and the second process are performed. This further improves the productivity of the tire 7. The tire 7 is further excellent in productivity. The manufacturing method of the tire 7 realizes further excellent productivity.

  As shown in FIG. 2, it is preferable that the third ribbon 36 and the first ribbon 32 and the second ribbon 34 have no overlap. By making the third ribbon 36, the first ribbon 32, and the second ribbon 34 overlap, the uniformity of the tire 7 can be improved. The tire 7 is excellent in uniformity.

  In FIG. 2, a double arrow Wa is the width of the third ribbon 36. A double-headed arrow Wb is the minimum axial distance between the first ribbon 32 and the second ribbon 34. The ratio (Wa / Wb) of the width Wa to the interval Wb is preferably 0.7 or more. By setting the ratio (Wa / Wb) to be 0.7 or more, the gap between the first ribbon 32 and the third ribbon 36 and the gap between the second ribbon 34 and the third ribbon 36 can be reduced. The tire 7 is excellent in uniformity. In this respect, the ratio (Wa / Wb) is more preferably equal to or greater than 0.8 and still more preferably equal to or greater than 0.9.

  The ratio (Wa / Wb) is preferably 1.0 or less. By setting the ratio (Wa / Wb) to 1.0 or less, the overlap between the first ribbon 32 and the third ribbon 36 and the overlap between the second ribbon 34 and the third ribbon 36 can be prevented. The tire 7 is excellent in uniformity.

  In FIG. 2, the double arrow W <b> 1 is the minimum distance between the first ribbon 32 and the third ribbon 36. The ratio (W1 / Wa) is preferably 0.2 or less. By setting the ratio (W1 / Wa) to 0.2 or less, the gap between the first ribbon 32 and the third ribbon 36 can be reduced. The tire 7 is excellent in uniformity. In this respect, the ratio (W1 / Wa) is more preferably equal to or less than 0.1 and still more preferably 0.0.

  In FIG. 2, the double arrow W <b> 2 is the minimum distance between the second ribbon 34 and the third ribbon 36. The ratio (W2 / Wa) is preferably 0.2 or less. By setting the ratio (W2 / Wa) to 0.2 or less, the gap between the second ribbon 34 and the third ribbon 36 can be reduced. The tire 7 is excellent in uniformity. In this respect, the ratio (W2 / Wa) is more preferably equal to or less than 0.1 and still more preferably 0.0.

  In the present invention, the size and angle of each member of the tire 7 are measured in a state where the tire 7 is incorporated in a regular rim and the tire 7 is filled with air so as to have a regular internal pressure. At the time of measurement, no load is applied to the tire 7. In the present specification, the normal rim means a rim defined in a standard on which the tire 7 depends. “Standard rim” in the JATMA standard, “Design Rim” in the TRA standard, and “Measuring Rim” in the ETRTO standard are regular rims. In the present specification, the normal internal pressure means an internal pressure defined in a standard on which the tire 7 depends. “Maximum air pressure” in JATMA standard, “maximum value” published in “TIRE LOAD LIMITS AT VARIOUS COLD INFLATION PRESSURES” in TRA standard, and “INFLATION PRESSURE” in ETRTO standard are normal internal pressures. In the case of the passenger car tire 7, the dimensions and angles are measured in a state where the internal pressure is 180 kPa.

  Hereinafter, the effects of the present invention will be clarified by examples. However, the present invention should not be construed in a limited manner based on the description of the examples.

[Example 1]
A pneumatic tire having the structure shown in FIG. 1 was produced. The size of this tire is “215 / 45R17 PCR”. The tire band has the structure shown in FIG. This is shown in FIG. 2 in the “band structure” column of Table 1. This band is formed by winding a first ribbon, a second ribbon, and a third ribbon. This is shown as “3” in the “Ribbon number” column of Table 1. In this tire, there is no overlap between the first ribbon and the third ribbon. The first ribbon and the third ribbon are just in contact. Therefore, the ratio (W1 / Wa) is zero. There is no overlap between the second and third ribbons. The second ribbon and the third ribbon are just in contact. Therefore, the ratio (W2 / Wa) is zero. The ratio (Wa / Wb) is 1.0.

  In forming this band, a former having a cylindrical drum and a first head, a second head, and a third head was used. The first ribbon was fed from the first head. In the first region of the tire, the tip of the first ribbon was disposed on the drum, and the first head was moved along with the rotation of the drum, and the first ribbon was wound spirally. The second ribbon was fed from the second head. In the second region of the tire, the tip of the second ribbon was placed on the drum, and the second head was moved along with the rotation of the drum, so that the second ribbon was wound spirally. The winding of the first ribbon and the winding of the second ribbon were performed simultaneously. The tip of the third ribbon was placed on the drum on the equator plane of the tire, and the third ribbon was wound in the circumferential direction by the rotation of the drum. The winding of the third ribbon was performed in parallel with the winding of the first ribbon and the winding of the second ribbon.

[Comparative Example 1]
A tire of Comparative Example 1 was obtained in the same manner as in Example 1 except that the band had the structure shown in FIG. This tire is a conventional tire. In this band, one ribbon is wound spirally. In forming this band, only one former head was used. The ribbon was fed from this head. Near one axial outer end of the tire, the tip of the ribbon was placed on the drum. The ribbon was spirally wound by moving the head to the other outer end of the tire as the drum rotated.

[Comparative Example 2]
A tire of Comparative Example 2 was obtained in the same manner as in Example 1 except that the band had the structure shown in FIG. This tire is a conventional tire. This band is formed by winding a first ribbon and a second ribbon. In forming this band, a former having a cylindrical drum and a first head and a second head was used. The first ribbon was fed from the first head. In the first region of the tire, the tip of the first ribbon was disposed on the drum, and the first head was moved along with the rotation of the drum, and the first ribbon was wound spirally. The second ribbon was fed from the second head. In the second region of the tire, the tip of the second ribbon was placed on the drum, and the second head was moved along with the rotation of the drum, so that the second ribbon was wound spirally. The winding of the first ribbon and the winding of the second ribbon were performed simultaneously.

[Example 2-4]
A tire of Example 2-4 was obtained in the same manner as in Example 1 except that the ratio (Wa / Wb) was as shown in Table 1. At this time, the distance W1 between the first ribbon and the third ribbon and the distance W2 between the second ribbon and the third ribbon were the same. The manufacturing method of the tire of Example 2-4 is the same as that of the tire of Example 1.

[Uniformity]
Radial force variation (RFV) was measured according to the conditions of the uniformity test specified in “JASO C607: 2000”. Twenty tires were measured for each prototype tire to obtain an average value of RFV. Based on this average value, the uniformity was evaluated. The results are shown in Table 1 below using an index with Comparative Example 1 as 100. Larger numbers are preferable.

[Band productivity]
The time required for band formation was measured, and the reciprocal thereof was taken as productivity. The results are shown in Table 1 below as index values with Comparative Example 1 taken as 100. The higher this number, the higher the evaluation.

  As shown in Table 1, the tire of the example has a higher evaluation than the tire of the comparative example. From this evaluation result, the superiority of the present invention is clear.

  The method described above can be applied to the manufacture of various tires.

DESCRIPTION OF SYMBOLS 1, 3 ... Band 2 ... Ribbon 4, 32 ... 1st ribbon 5, 34 ... 2nd ribbon 6 ... Clearance 7 ... Tire 8 ... Tread 9 ... Side Wall 10 ... Clinch 11 ... Bead 12 ... Carcass 14 ... Belt 14a ... Inner layer 14b ... Outer layer 16 ... Band 18 ... Edge band 20 ... Inner liner 22 ... chafer 24 ... tread surface 25 ... groove 26 ... core 28 ... apex 30 ... carcass ply 36 ... third ribbon 38 ... code 40 ... Topping rubber 42 ... Drum 44 ... First head 46 ... Second head 48 ... Third head

Claims (4)

A tire having a tread whose outer surface forms a tread surface and a band located radially inward of the tread;
The band is configured by winding a first ribbon, a second ribbon, and a third ribbon,
Each of the first ribbon, the second ribbon, and the third ribbon includes a cord extending in a length direction,
When the region on the outer side in the axial direction of the equator plane in the tire is the first region, and the region on the outer side in the axial direction of the equator surface is the second region,
In the first region, the first ribbon is spirally wound in a substantially circumferential direction from the inner side in the axial direction to the outer side,
In the second region, the second ribbon is spirally wound in a substantially circumferential direction from the inner side in the axial direction toward the outer side,
A pneumatic tire in which the third ribbon is wound in the circumferential direction on the equator plane.   In the axial direction, when the minimum interval between the first ribbon and the second ribbon is Wb and the width of the third ribbon is Wa, the ratio (Wa / Wb) of the width Wa to the interval Wb is 0. The pneumatic tire according to claim 1, which is 0.7 or more and 1.0 or less. A method of manufacturing a tire comprising a tread whose outer surface forms a tread surface and a band located radially inward of the tread,
Using a former comprising a rotatable cylindrical drum, a first head for feeding the first ribbon, a second head for feeding the second ribbon, and a third head for feeding the third ribbon,
Including the step of obtaining a band by winding the first ribbon, the second ribbon and the third ribbon in the drum,
When the region on the outer side in the axial direction of the equator plane in the tire is the first region, and the region on the outer side in the axial direction of the equator surface is the second region,
The process of obtaining the band is as follows:
The tip of the first ribbon sent out from the first head is disposed on the drum, and the drum is rotated and the first head is moved from the inner side toward the outer side in the axial direction. A first step in which the first ribbon is spirally wound in the region;
The tip of the second ribbon sent out from the second head is disposed on the drum, and the drum is rotated and the second head is moved from the inner side toward the end in the axial direction. A second step in which the second ribbon is spirally wound in the region;
The tip of the third ribbon fed from the third head is disposed on the drum, and the third ribbon is wound in the circumferential direction on the equator plane of the tire by rotating the drum. And a third step
A tire manufacturing method in which the first step and the second step are performed simultaneously.   The method for manufacturing a tire according to claim 3, wherein the third step is performed while the first step and the second step are being performed.

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