JP2012125992A - Method for manufacturing tire - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a vulcanizer 30 which can stably manufacture a tire of high quality, and a method for manufacturing tire using the same.SOLUTION: The vulcanizer 30 includes the bead ring 50 coming into contact with a low cover R to form the bead 94 of the tire, a bladder 40 which can press the low cover R from the inner surface thereof and the disk-shaped support ring 42 positioned inside the axial direction of the bead ring 50. A part of the bladder 40 is positioned between the bead ring 50 and the support ring 42. The diameter DA satisfies numerical formula (1): DB×25.4-40.0≤DA≤DB×25.4-15.0, wherein DA is the outer diameter of the support ring 42 and DB is the rim diameter of the tire.

Description

  The present invention relates to a tire manufacturing method.

  A vulcanizer is used for manufacturing the tire. FIG. 5 shows a part of a conventional vulcanizing apparatus 2. The vulcanizing device 2 includes a mold 4, a bladder 6, and a center portion 8. In FIG. 5, an alternate long and short dash line CL is a center line of the vulcanizer 2.

  The mold 4 is composed of a number of members. These members are combined to form a cavity surface that forms the outer surface of the tire. FIG. 5 shows the lower side plate 10 and the lower bead ring 12 among these members. The side plate 10 is substantially ring-shaped. The side plate 10 includes a molding surface 14 that forms a part of the cavity surface. Although not shown, the molding surface 14 abuts on a raw cover (also referred to as an uncrosslinked tire) to form a tire sidewall. The bead ring 12 is located on the radially inner side of the side plate 10. The bead ring 12 is substantially ring-shaped. The bead ring 12 includes a molding surface 16 that forms another part of the cavity surface. Although not shown, the molding surface 16 abuts the raw cover and forms a tire bead. The bead ring 12 further includes a contact surface 18 that can come into contact with the bladder 6.

  The bladder 6 is located inside the mold 4. The bladder 6 is made of a crosslinked rubber. The bladder 6 is configured so that its interior is filled with gas. FIG. 5 shows the bladder 6 before gas filling.

  The central portion 8 is located at the center of the vulcanizer 2. The central portion 8 includes an upper clamp 20 and a lower clamp 22. The upper clamp 20 includes an upper jaw 24 and a lower jaw 26. One end of the aforementioned bladder 6 is sandwiched between the upper jaw 24 and the lower jaw 26, and the other end is sandwiched between the bead ring 12 and the lower clamp 22, and is fixed to the vulcanizing device 2. Yes.

  In the tire manufacturing method, a raw cover is put into the mold 4. Although not shown, this raw cover is placed on the mold 4 so that the beads can come into contact with the molding surface 16 of the bead ring 12.

  The bladder 6 is filled with gas. By this filling, the bladder 6 expands and the raw cover is deformed. This deformation is called shaping. The mold 4 is tightened and the internal pressure of the bladder 6 is increased. The raw cover is sandwiched between the mold 4 and the bladder 6 and pressed. The raw cover is heated by heat conduction from the bladder 6 and the mold 4. The rubber composition of the raw cover flows by pressurization and heating. The rubber causes a crosslinking reaction by heating, and a tire is obtained. From the viewpoint of stably producing high-quality tires, various studies have been made on vulcanizing apparatuses. Examples of this study are disclosed in Japanese Patent Laid-Open Nos. 7-24835 and 6-143288.

Japanese Patent Laid-Open No. 7-24835 JP-A-6-143288

  FIG. 6 shows the state of the vulcanizer 2 in the shaping process. In FIG. 6, R represents a raw cover. As shown, the inflated bladder 6 lifts the raw cover R. The bead 28 of the raw cover R is separated from the molding surface 16 of the bead ring 12.

  As described above, after the shaping process, the mold 4 is closed. The raw cover R is accommodated in a cavity (not shown) formed between the mold 4 and the bladder 6. At this time, the tip of the bead 28 may be sandwiched between the contact surface 18 of the bead ring 12 and the bladder 6. In this case, twist is generated at the tip of the bead 28 in the molded tire. In FIG. 7, what is indicated by T is a twist generated at the tip of the bead 28 of the tire 29. This twist impairs the appearance. The twist can be removed by cutting or the like, but this work takes time.

  An object of the present invention is to provide a vulcanizing apparatus capable of stably producing a high-quality tire and a production method using the same.

The tire vulcanizing apparatus according to the present invention includes a bead ring that abuts against a raw cover to form a tire bead, a bladder that can press the raw cover from its inner surface, and a disk-shaped support that is positioned on the inner side in the axial direction of the bead ring. With a ring. A part of the bladder is located between the bead ring and the support ring. When the outer diameter of the support ring is DA and the rim diameter of the tire is DB, the outer diameter DA satisfies the following formula (1).
DB × 25.4-40.0 ≦ DA ≦ DB × 25.4-15.0 (1)

Preferably, in the tire vulcanizer, the outer diameter DA satisfies the following mathematical formula (2).
DB × 25.4-37.7 ≦ DA ≦ DB × 25.4-17.2 (2)

The tire manufacturing method according to the present invention includes:
(1) a step of obtaining a raw cover by preforming;
(2) It has a bead ring that makes contact with the raw cover to form a tire bead, a bladder that can press the raw cover from its inner surface, and a disk-shaped support ring that is positioned on the inner side in the axial direction of the bead ring. A step of inserting the raw cover into a vulcanizer in which a part of the bladder is located between the bead ring and the support ring;
(3) expanding the bladder and pressing the raw cover from the inner surface;
The raw cover includes a step of pressurizing and heating. When the outer diameter of the support ring is DA and the rim diameter of the tire is DB, the outer diameter DA satisfies the following formula (1).
DB × 25.4-40.0 ≦ DA ≦ DB × 25.4-15.0 (1)

  According to the vulcanizing apparatus according to the present invention, a high-quality tire can be manufactured stably.

FIG. 1 is a sectional view showing a part of a vulcanizing apparatus according to an embodiment of the present invention. FIG. 2 is a sectional view showing a part of the vulcanizing apparatus of FIG. FIG. 3 is a plan view showing a mounting state of the support ring. FIG. 4 is a cross-sectional view showing the state of the vulcanizer in the shaping process. FIG. 5 is a cross-sectional view showing a part of a conventional vulcanizing apparatus. FIG. 6 is a cross-sectional view showing a use state of the vulcanizing apparatus of FIG. FIG. 7 is a cross-sectional perspective view showing a part of a tire manufactured using the vulcanizing apparatus of FIG. 5.

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

  The vulcanizing apparatus 30 shown in FIGS. 1 and 2 includes a container 32, a pair of upper and lower platens 34, a mold 36, a central portion 38, a bladder 40, and a support ring 42. 1 and 2, the left-right direction is the radial direction, and the up-down direction is the axial direction. In FIG. 1, what is indicated by R is a raw cover (also referred to as an uncrosslinked tire).

  The container 32 is located outside the mold 36 in the radial direction. The container 32 has a ring shape. The container 32 extends in the circumferential direction along the outer peripheral surface of the mold 36. The container 32 is configured so that the inside thereof is filled with a heating medium such as steam. The container 32 can heat the mold 36.

  The platen 34 is provided on each of the upper side and the lower side of the mold 36. Each platen 34 has a disk shape. The platen 34 is configured so that the inside thereof is filled with a heating medium. The platen 34 can heat the mold 36.

  The mold 36 includes a sector shoe 44, a segment 46, a pair of upper and lower side plates 48, a pair of upper and lower bead rings 50, an upper base plate 52a, and a lower base plate 52b. This mold 36 is a so-called “split mold”.

  The sector shoe 44 is located inside the container 32 in the radial direction. Although not shown, the mold 36 includes a plurality of sector shoes 44. These sector shoes 44 are arranged in a ring shape. The planar shape of each sector shoe 44 is substantially arcuate.

  The segment 46 is located on the radially inner side of the sector shoe 44. Although not shown, the mold 36 includes a plurality of segments 46. These segments 46 are arranged in a ring shape. The planar shape of each segment 46 is substantially arcuate. The segment 46 has a first molding surface 54 on its inner surface. The first molding surface 54 abuts on the raw cover R and forms the tread surface of the tire. The molding surface is provided with a crest 56 corresponding to the groove of the tread surface.

  The number of segments 46 is usually 3 or more and 20 or less. In a typical mold 36, the number of segments 46 is, for example, 8 or 9. Since each segment 46 is matched to a respective sector shoe 44, the number of sector shoes 44 is equivalent to that of segment 46. Therefore, the number of sector shoes 44 is usually 3 or more and 20 or less. In a typical mold 36, the number of sector shoes 44 is, for example, eight or nine.

  The side plate 48 is located on the radially inner side of the segment 46. The side plate 48 is substantially ring-shaped. The side plate 48 is not divided. The side plate 48 is fixed to the base plate 52. The side plate 48 includes a second molding surface 58 on its inner surface. The second molding surface 58 is in contact with the raw cover R and forms the sidewall of the tire.

  The bead ring 50 is located inside the side plate 48 in the radial direction. In this mold 36, the bead ring 50 is fixed to the side plate 48. The bead ring 50 is substantially ring-shaped. The bead ring 50 is not divided. The bead ring 50 includes a third molding surface 60 and a contact surface 62 on its inner surface. The third molding surface 60 abuts the raw cover R and forms a tire bead. The contact surface 62 extends radially inward from the third molding surface 60. As shown, the contact surface 62 can abut the bladder 40.

  The mold 36 shown in FIG. 1 is in a closed state. In this state, the segment 46, the side plate 48, and the bead ring 50 are combined to form the cavity surface 64. The cavity surface 64 includes a first molding surface 54 of the segment 46, a second molding surface 58 of the side plate 48, and a third molding surface 60 of the bead ring 50. The cavity surface 64 contacts the raw cover R and forms the outer surface of the tire.

  The mold 36 is configured so that the sector shoe 44 can slide radially outward when the container 32 is lifted upward. The segment 46 is fixed to the sector shoe 44. For this reason, when the container 32 rises and the sector shoe 44 slides, the segment 46 can slide radially outward. When the upper base plate 52a is raised, the upper side plate 48a and the upper bead ring 50a are raised. In this way, the mold 36 is opened. The vulcanizer 30 in this state is shown in FIG. The segment 46 slides radially inward as the container 32 descends, and the upper side plate 48a and the upper bead ring 50a descend as the upper base plate 52a descends. In this way, the mold 36 is closed.

  The bladder 40 is located inside the mold 36. The bladder 40 is made of a crosslinked rubber. The bladder 40 has a bag shape. The bladder 40 is configured so that the inside thereof is filled with a pressurized medium. When the bladder 40 is filled with the pressurized medium, the bladder 40 expands. When the pressurized medium is discharged from the bladder 40, the bladder 40 contracts. An example of the pressurizing medium is a gas such as nitrogen adjusted to a predetermined temperature.

  The bladder 40 shown in FIG. 1 is in an expanded state. The expanded bladder 40 can press the raw cover R from its inner surface. As illustrated, a part of the bladder 40 is in contact with the raw cover R. Another part of the bladder 40 is in contact with the contact surface 62 of the bead ring 50. In other words, the bladder 40 includes a main portion 66 that can contact the raw cover R and a pair of sub-portions 68 that can contact the contact surface 62. Each sub part 68 extends substantially inward in the radial direction from the main part 66.

  As shown in FIG. 2, the central portion 38 is located inside the bladder 40. The central portion 38 is located at the center of the vulcanizer 30. The center portion 38 includes an upper clamp 70, a lower clamp 72, and a center post 74. The upper clamp 70 includes an upper jaw 76 and a lower jaw 78. One end of the bladder 40 is sandwiched between the upper jaw 76 and the lower jaw 78, and the other end is sandwiched between the lower bead ring 50b and the lower clamp 72. It is fixed. The center post 74 is configured to be slidable in the axial direction with respect to the lower clamp 72. In the vulcanizer 30, the upper clamp 70 is fixed to the center post 74. For this reason, one end of the bladder 40 can slide in the axial direction in accordance with the slide of the center post 74. The vulcanizer 30 is configured such that one end of the bladder 40 can slide in the axial direction with respect to the other end of the bladder 40. The bladder 40 shown in FIG. 2 is in a state before being filled with the pressurized medium.

  The support ring 42 is located on the inner side in the axial direction of the lower bead ring 50b. The support ring 42 is fixed to the lower clamp 72 with a pin 80. The support ring 42 extends radially outward from the central portion 38.

  FIG. 3 shows the support ring 42 attached to the lower clamp 72. As shown, the outline of the support ring 42 is a circle. The support ring 42 is composed of a disk-shaped plate.

  The support ring 42 includes a main port 82 and a pair of sub ports 84 that are located outside the main port 82. The main port 82 is located at the center of the support ring 42. The shape of the main port 82 corresponds to the shape of the center post 74. Each sub-portion 84 includes a main hole 86 and a guide hole 88 extending from the main hole 86 in the circumferential direction. The main hole 86 and the guide hole 88 are continuous. The size of the main hole 86 is larger than the size of the base 90 of the pin 80. The width of the pedestal 90 is larger than the width of the guide hole 88.

  In this vulcanizer 30, the support ring 42 is fixed to the lower clamp 72 as follows. The main port 82 of the support ring 42 is fitted into the center post 74 of the center portion 38. The pedestal 90 of the pin 80 is passed through the main hole 86. The support ring 42 is rotated in the direction indicated by the arrow A. By this rotation, the shaft 92 of the pin 80 is fitted into the guide hole 88, and the fixing of the support ring 42 to the lower clamp 72 is completed. In FIG. 3, the dotted line indicates the position of the sub-opening 84 when the pedestal 90 of the pin 80 is passed through the main hole 86.

  Since the width of the base 90 of the pin 80 is larger than the width of the guide hole 88, the support ring 42 can be securely fixed to the lower clamp 72. If the support ring 42 is rotated in the direction indicated by the arrow A after passing the pedestal 90 of the pin 80 through the main hole 86, the support ring 42 is fixed to the lower clamp 72, so that the support ring 42 can be easily attached. It is.

  Using this vulcanizer 30, a tire is manufactured as follows. In this manufacturing method, the raw cover R is obtained by preforming. The raw cover R is put into the opened mold 36. Although not shown, the inserted beads of the raw cover R are in contact with the third molding surface 60b of the lower bead ring 50b. The bladder 40 is filled with nitrogen gas as a pressurized medium. The filling of the nitrogen gas causes the bladder 40 to expand. The bladder 40 contacts the inner surface of the raw cover R. With this bladder 40, the shape of the raw cover R is adjusted. This process is also referred to as a shaping process.

  FIG. 4 shows the state of the vulcanizer 30 in the shaping process. The main portion 66 of the expanded bladder 40 is in contact with the raw cover R. The lower portion 68b of the bladder 40 located on the lower side is sandwiched between the lower bead ring 50b and the support ring 42. In other words, a part of the bladder 40 is located between the bead ring 50 b and the support ring 42. The support ring 42 can prevent the auxiliary portion 68b from being separated from the bead ring 50b. Since the sub-portion 68b is prevented from being lifted with respect to the bead ring 50b, the bead 94 of the low cover R can be held in contact with the third molding surface 60b of the bead ring 50b. In the vulcanizing device 30, the bead 94 is effectively prevented from being separated from the third molding surface 60b in the shaping process.

  The mold 36 is closed, and steam as a heating medium is supplied to each of the container 32, the upper platen 34, and the lower platen 34. The mold 36 is heated by the container 32, the upper platen 34, and the lower platen 34. The raw cover R is heated by the mold 36. Nitrogen gas is further supplied into the bladder 40. By supplying this nitrogen gas, the internal pressure of the bladder 40 is further increased. The raw cover R is pressed against the cavity surface 64 of the mold 36 by the bladder 40 and pressurized. The raw cover R in this state is shown in FIG. At the same time, the raw cover R is heated. The rubber composition flows by pressurization and heating. The rubber causes a crosslinking reaction by heating, and a tire is obtained.

  In the vulcanizing device 30, the mold 36 is closed in a state where the beads 94 of the raw cover R are in contact with the third molding surface 60b. Therefore, the tip of the bead 94 is pressurized and heated without being sandwiched between the sub-portion 68b of the bladder 40 and the contact surface 62b of the bead ring 50b. This vulcanizing device 30 can effectively prevent the occurrence of twist of the manufactured tire. The manufacturing method using the vulcanizer 30 can stably manufacture a high-quality tire.

  In this vulcanizing apparatus 30, the edge 96 of the support ring 42 is formed between the third molding surface 60b of the bead ring 50b and the contact surface 62b in the radial direction from the viewpoint that the raw cover R can be easily put into the mold 36. It is preferably located at the same level as or inside the boundary 98. As shown in the figure, in the vulcanizing device 30, the edge 96 of the support ring 42 is located inside the boundary 98 in the radial direction.

  In the vulcanizing device 30, the outer diameter of the support ring 42 is set in consideration of the position of the tip of the bead 94 of the raw cover R. In the vulcanizing device 30, the edge 96 of the support ring 42 is disposed at an appropriate position. According to this manufacturing method, it is easy to put the raw cover R into the mold 36. In the tire obtained by this manufacturing method, the occurrence of twist is effectively prevented. This manufacturing method can stably manufacture a high-quality tire.

  In FIG. 2, a double arrow DA / 2 represents the radius of the support ring 42. Therefore, the outer diameter of the support ring 42 is indicated by DA. In this vulcanizing device 30, from the viewpoint that high-quality tires can be produced stably, when the nominal rim diameter in the JATMA standard of the manufactured tire is DB, the outer diameter DA is expressed by the following formula (1). Set to meet. The unit of the outer diameter DA is mm, and the unit of the rim diameter DB is inches.

DB × 25.4-40.0 ≦ DA ≦ DB × 25.4-15.0 (1)

  In this manufacturing method, from the viewpoint that high-quality tires can be stably produced, the nominal rim diameter DB is preferably 17 inches or more, and more preferably 20 inches or less.

  When the nominal DB of the rim diameter of the manufactured tire is 17 inches, the outer diameter DA obtained based on the above formula (1) is 391.8 mm or more and 416.8 mm or less. By setting the outer diameter DA to 391.8 mm or more, the raw cover R is pressurized and heated without the bead 94 being sandwiched between the bladder 40 and the bead ring 50b. By setting the outer diameter DA to 416.8 mm or less, the raw cover R can be easily put into the mold 36. The support ring 42 having the outer diameter DA that satisfies the above formula (1) can contribute to stable production of high-quality tires.

  When the nominal DB of the rim diameter of the manufactured tire is 18 inches, the outer diameter DA obtained based on the above formula (1) is 417.2 mm or more and 442.2 mm or less. By setting the outer diameter DA to 417.2 mm or more, the raw cover R is pressurized and heated without the bead 94 being sandwiched between the bladder 40 and the bead ring 50b. By setting the outer diameter DA to 442.2 mm or less, the raw cover R can be easily put into the mold 36. The support ring 42 having the outer diameter DA that satisfies the above formula (1) can contribute to stable production of high-quality tires.

  When the nominal DB of the rim diameter of the manufactured tire is 19 inches, the outer diameter DA obtained based on the above formula (1) is not less than 442.6 mm and not more than 467.6 mm. By setting the outer diameter DA to 442.6 mm or more, the raw cover R is pressurized and heated without the bead 94 being sandwiched between the bladder 40 and the bead ring 50b. By setting the outer diameter DA to 467.6 mm or less, the raw cover R can be easily put into the mold 36. The support ring 42 having the outer diameter DA that satisfies the above formula (1) can contribute to stable production of high-quality tires.

  When the nominal DB of the rim diameter of the manufactured tire is 20 inches, the outer diameter DA obtained based on the above formula (1) is 468.0 mm or more and 493.0 mm or less. By setting the outer diameter DA to 468.0 mm or more, the raw cover R is pressurized and heated without the bead 94 being sandwiched between the bladder 40 and the bead ring 50b. By setting the outer diameter DA to be equal to or less than 493.0 mm, the raw cover R can be easily put into the mold 36. The support ring 42 having the outer diameter DA that satisfies the above formula (1) can contribute to stable production of high-quality tires.

  In this manufacturing method, from the viewpoint that a high-quality tire can be produced more stably, it is preferable that the outer diameter DA satisfies the following formula (2) using a nominal DB of the rim diameter of the manufactured tire.

DB × 25.4-37.7 ≦ DA ≦ DB × 25.4-17.2 (2)

  When the nominal DB of the rim diameter of the manufactured tire is 17 inches, the preferable outer diameter DA obtained based on the above formula (2) is 394.1 mm or more and 414.6 mm or less. By setting the outer diameter DA to 394.1 mm or more, the raw cover R is pressurized and heated without the bead 94 being sandwiched between the bladder 40 and the bead ring 50b. By setting the outer diameter DA to 414.6 mm or less, the raw cover R can be easily put into the mold 36. The support ring 42 having the outer diameter DA that satisfies the mathematical formula (2) can effectively contribute to stable production of high-quality tires.

  When the nominal DB of the rim diameter of the manufactured tire is 18 inches, the preferable outer diameter DA obtained based on the above formula (2) is 419.5 mm or more and 440.0 mm or less. By setting the outer diameter DA to 419.5 mm or more, the raw cover R is pressurized and heated without the bead 94 being sandwiched between the bladder 40 and the bead ring 50b. By setting the outer diameter DA to 440.0 mm or less, the raw cover R can be easily put into the mold 36. The support ring 42 having the outer diameter DA that satisfies the mathematical formula (2) can effectively contribute to stable production of high-quality tires.

  When the nominal DB of the rim diameter of the manufactured tire is 19 inches, the preferable outer diameter DA obtained based on the above formula (2) is 444.9 mm or more and 465.4 mm or less. By setting the outer diameter DA to 444.9 mm or more, the raw cover R is pressurized and heated without the bead 94 being sandwiched between the bladder 40 and the bead ring 50b. By setting the outer diameter DA to 465.4 mm or less, the raw cover R can be easily put into the mold 36. The support ring 42 having the outer diameter DA that satisfies the mathematical formula (2) can effectively contribute to stable production of high-quality tires.

  When the nominal DB of the rim diameter of the manufactured tire is 20 inches, the preferable outer diameter DA obtained based on the above formula (2) is 470.3 mm or more and 490.8 mm or less. By setting the outer diameter DA to 470.3 mm or more, the low cover R is pressurized and heated without the bead 94 being sandwiched between the bladder 40 and the bead ring 50b. By setting the outer diameter DA to 490.8 mm or less, the raw cover R can be easily put into the mold 36. The support ring 42 having the outer diameter DA that satisfies the mathematical formula (2) can effectively contribute to stable production of high-quality tires.

  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]
One thousand tires were manufactured using a vulcanizing apparatus having the basic configuration shown in FIGS. The tire size was 225 / 55R17. Therefore, the rim diameter nominal DB in the JATMA standard is 17 inches. The outer diameter DA of the support ring was 414.1 mm. The bead diameter of the raw cover was 434.1 mm. This bead diameter is obtained based on the contour of the inner edge of the raw cover. In the table, a case where a support ring is provided is indicated by “A”.

[Example 2-3 and Comparative Example 2-4]
1000 tires were manufactured in the same manner as in Example 1 except that the outer diameter DA was changed. In Comparative Examples 2 and 3, tire production was stopped because the raw cover could not be put into the mold.

[Comparative Example 1]
1000 tires were manufactured in the same manner as in Example 1 except that no support ring was provided. In the table, the case where no support ring is provided is indicated by “B”.

[Example 4]
One thousand tires were manufactured using a vulcanizing apparatus having the basic configuration shown in FIGS. The tire size was 225 / 55R18. Therefore, the nominal DB of the rim diameter in the JATMA standard is 18 inches. The outer diameter DA of the support ring was 440.0 mm. The bead diameter of the raw cover was 460.0 mm.

[Example 5-6 and Comparative Example 6-8]
1000 tires were manufactured in the same manner as in Example 4 except that the outer diameter DA was changed. In Comparative Examples 6 and 7, the production of the tire was stopped because the raw cover could not be put into the mold.

[Comparative Example 5]
1000 tires were manufactured in the same manner as in Example 4 except that no support ring was provided.

[Example 7]
One thousand tires were manufactured using a vulcanizing apparatus having the basic configuration shown in FIGS. The tire size was 225 / 45R19. Therefore, the nominal DB of the rim diameter in the JATMA standard is 19 inches. The outer diameter DA of the support ring was 465.4 mm. The bead diameter of the raw cover was 485.4 mm.

[Example 8-9 and Comparative Example 10-12]
1000 tires were manufactured in the same manner as in Example 7 except that the outer diameter DA was changed. In Comparative Examples 10 and 11, since the raw cover could not be put into the mold, the tire production was stopped.

[Comparative Example 9]
1000 tires were manufactured in the same manner as in Example 7 except that no support ring was provided.

[Example 10]
One thousand tires were manufactured using a vulcanizing apparatus having the basic configuration shown in FIGS. The tire size was 265 / 45R20. Therefore, the nominal DB of the rim diameter in the JATMA standard is 20 inches. The outer diameter DA of the support ring was 490.8 mm. The bead diameter of the raw cover was 510.8 mm.

[Examples 11-12 and Comparative Examples 14-16]
1000 tires were manufactured in the same manner as in Example 10 except that the outer diameter DA was changed. In Comparative Examples 14 and 15, the production of the tire was stopped because the raw cover could not be put into the mold.

[Comparative Example 13]
1000 tires were manufactured in the same manner as in Example 10 except that no support ring was provided.

[Evaluation of formability]
The appearance of the manufactured tire was observed. The number of tires in which the occurrence of twist is recognized is shown in Table 1, Table 2, Table 3, and Table 4 below. In the table, “−” indicates that the raw cover could not be put into the mold and the tire could not be manufactured. The case where the number of tires in which the occurrence of twist is recognized is less than 5 is acceptable.

  As shown in Tables 1 to 4, the vulcanizing apparatus of the example has a higher evaluation than the vulcanizing apparatus of the comparative example. From this evaluation result, the superiority of the present invention is clear.

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

2, 30 ... Vulcanizing device 4, 36 ... Mold 6, 40 ... Bladder 8, 38 ... Central part 10, 48 ... Side plate 12, 50 ... Bead ring 14, 16 ... Molding surface 18 ... Contact surface 42 ... Support ring 46 ... Segment 60 ... Third molding surface 62 ... Contact surface 94 ... Bead

Claims (3)

It has a bead ring that abuts against the raw cover to form a tire bead, a bladder that can press the raw cover from its inner surface, and a disk-shaped support ring that is located on the inner side in the axial direction of the bead ring.
Part of this bladder is located between this bead ring and this support ring,
When the outer diameter of this support ring is DA and the rim diameter of the tire is DB,
A tire vulcanizer in which the outer diameter DA satisfies the following formula (1).
DB × 25.4-40.0 ≦ DA ≦ DB × 25.4-15.0 (1) The tire vulcanizer according to claim 1, wherein the outer diameter DA satisfies the following mathematical formula (2).
DB × 25.4-37.7 ≦ DA ≦ DB × 25.4-17.2 (2) A process of obtaining a raw cover by preforming;
A bead ring that abuts against the raw cover to form a tire bead, a bladder that can press the raw cover from its inner surface, and a disc-shaped support ring that is located on the inner side in the axial direction of the bead ring. A step in which the raw cover is put into a vulcanizing apparatus whose part is located between the bead ring and the support ring;
Expanding the bladder and pressing the raw cover from the inner surface;
The raw cover includes a step of applying pressure and heating,
When the outer diameter of this support ring is DA and the rim diameter of the tire is DB,
A tire manufacturing method in which the outer diameter DA satisfies the following mathematical formula (1).
DB × 25.4-40.0 ≦ DA ≦ DB × 25.4-15.0 (1)

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