JP2010076344A - Mold for tire - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a mold for tire improving tire performance by suppressing deformation of segments. <P>SOLUTION: A tire molding device 1 includes a mold 2 and a container 3. The mold 2 includes a plurality of segments 4 arranged in the circumferential direction, a plurality of sector shoes 5 arranged in the circumferential direction and a side plate 6. Each sector shoe 5 is attached to each segment 4. Split faces 16 of the segments 4 are brought into contact with each other in the mold 2 in the closed state. The sector shoe 5 is brought into contact with the other sector shoe 5 or the side plate 6 in the mold 2 in the closed state. Preferably, split faces 18 of the sector shoes 5 are brought into contact with each other in the mold in the closed state. The sector shoe may be brought into contact with the side plate 6 in the closed state. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a tire mold.

  In the tire vulcanization process, a mold is used. Molds are roughly classified into split molds and two-piece molds. In the vulcanization process, a preformed raw cover (also referred to as an unvulcanized tire) is put into a mold. The raw cover is heated while being pressurized in a cavity formed by the mold and the bladder. The rubber composition of the raw cover flows in the cavity by pressurization and heating. The rubber causes a crosslinking reaction by heating, and a tire is obtained. When gas is left between the cavity surface of the mold and the raw cover during pressurization, a bear is formed on the surface of the tire. Bears reduce tire quality.

  The split mold has arc-shaped segments. A ring-shaped cavity surface is formed by arranging a large number of segments. The boundary of a segment with an adjacent segment is called a “dividing plane”. In the case of the split mold, the gas is discharged not only through the vent hole but also through this split surface. This discharge prevents bears. Since gas is discharged through the dividing surface, the split mold contributes to suppression of spew.

International Publication WO 03/008169 A1, Japanese Patent Application Laid-Open No. 5-220753, Japanese Patent Application Laid-Open No. 5-220748, and Japanese Patent Application Laid-Open No. 2002-361632 disclose a split mold considering gas discharge from a dividing surface. Japanese Patent Laid-Open No. 8-20026 discloses a split mold in which the hardness of the corners of a segment is defined in consideration of durability and maintenance. Japanese Patent Laying-Open No. 2005-59510 discloses a split mold in which a gap for absorbing elongation due to thermal expansion is provided on a dividing surface of a segment.
International Publication WO03 / 008169 A1 Japanese Patent Laid-Open No. 5-220753 JP-A-5-220748 JP 2002-361632 A JP-A-8-20026 JP 2005-59510 A

  The split mold is opened and closed by moving each of the segments in the radial direction. In the split mold in the opened state, the split surfaces of the segments are separated from each other. In the split mold in the closed state, the split surfaces of the segments are in contact with each other.

  During molding, the mold is closed by a large pressure. High pressure is required to maintain a closed state against the internal pressure of the bladder. Therefore, a large contact pressure acts on the segment dividing surface during molding. The segment can be deformed by this contact pressure. With repeated use, the segments can be gradually deformed. In particular, an aluminum alloy segment is soft and easily deformed. Due to the deformation of the segment, the gap between the dividing surfaces can be excessive. When the rubber composition enters the gap, burrs are generated. Further, the roundness of the tire may be reduced due to the deformation of the segment.

  An object of the present invention is to provide a tire mold that can suppress deformation of a segment and improve tire performance.

  The tire mold according to the present invention includes a plurality of segments arranged in the circumferential direction, a plurality of sector shoes arranged in the circumferential direction, and a side plate. Each of the sector shoes is attached to each of the segments. In a state where the mold is closed, the divided surfaces of the segments are in contact with each other. When the mold is closed, the sector shoe is in contact with another sector shoe or side plate.

  Preferably, the divided surfaces of the sector shoes are in contact with each other when the mold is closed.

  Preferably, the sector shoe is in contact with the side plate when the mold is closed.

  According to the mold of the present invention, the contact pressure of the segment dividing surface is relaxed, and the deformation of the segment is suppressed.

  Hereinafter, the present invention will be described in detail based on preferred embodiments with appropriate reference to the drawings. In the present application, “radial direction” means a radial direction of a tire molded by a mold.

  FIG. 1 is a plan view showing a part of a tire molding apparatus 1 according to the first embodiment of the present invention. FIG. 2 is a cross-sectional view taken along line II-II in FIG. FIG. 3 is a cross-sectional view taken along line III-III in FIG. FIG. 3 is a partial cross-sectional view of the tire molding apparatus 1.

  The tire molding apparatus 1 includes a tire mold 2 and a container 3. Although not shown, the tire molding device 1 further includes a lower plate (base plate), an upper plate, a heating plate, and the like.

  The mold 2 includes a plurality of segments 4, a plurality of sector shoes 5, a pair of upper and lower side plates 6, and a pair of upper and lower bead rings 8.

  The planar shape of the segment 4 is substantially arcuate. The plurality of segments 4 are arranged in the circumferential direction. A large number of segments 4 are arranged in a ring shape. Thus, the segment 4 is divided in the circumferential direction. The segment 4 is equally divided in the circumferential direction. The segment 4 has a cavity surface 10. The cavity surface 10 molds the tread surface of the tire. Except for the pattern shape of the cavity surface 10, all the segments 4 are the same.

  The number of segments 4 is usually 3 or more and 20 or less. In a typical mold 2, the number of segments 4 is, for example, 8 or 9. The side plate 6 and the bead ring 8 are substantially ring-shaped. The side plate 6 and the bead ring 8 are not divided. This mold 2 is a so-called “split mold”.

  The sector shoe 5 is attached to the outer side in the radial direction of the segment 4. The segment 4 is fixed to the sector shoe 5. Although not shown, the segment 4 is screwed to the sector shoe 5. The plurality of sector shoes 5 are arranged in the circumferential direction. A large number of sector shoes 5 are arranged in a ring shape. Thus, the sector shoe 5 is divided in the circumferential direction. The sector shoe 5 is equally divided in the circumferential direction. All sector shoes 5 are the same.

  The sector shoe 5 is divided into the same number as the segment 4. One segment 4 is attached to one sector shoe 5. The segment 4 and the sector shoe 5 have a one-to-one correspondence. The shape of the inner surface 12 of the sector shoe 5 corresponds to the shape of the outer surface 14 of the segment 4 (see FIG. 2). The inner surface 12 of the sector shoe 5 and the outer surface 14 of the segment 4 are in surface contact. The segment 4 is held by the sector shoe 5.

  The container 3 has a ring shape. The container 3 is not divided. A plurality of sector shoes 5 are arranged in the circumferential direction along the inner peripheral surface of the container 3.

  1, 2 and 3 show the tire mold 2 in a closed state. In a state where the mold 2 is heated to the temperature at which the tire is molded and the mold 2 is closed, the dividing surface 16 of the segment 4 is in contact with the dividing surface 16 of the other adjacent segment 4. That is, the divided surfaces 16 are in contact with each other in a state where the mold 2 is heated to the temperature at the time of tire molding and the mold 2 is closed. This contact is a surface contact. This contact is substantially a full surface contact. That is, in this contact, the substantially entire surface of the dividing surface 16 and the substantially entire surface of the other dividing surface 16 are in contact. FIG.1 and FIG.3 has shown the mold 2 heated to the temperature at the time of tire shaping | molding.

  In a state where the mold 2 is closed, the dividing surface 18 of the sector shoe 5 is in contact with the dividing surface 18 of another adjacent sector shoe 5. That is, the divided surfaces 18 are in contact with each other in a state where the mold 2 is closed. This contact is a surface contact. This contact is a partial contact. That is, in this contact, a part of the dividing surface 18 is in contact with a part of the other dividing surface 18.

  In the mold 2 at 25 ° C., the divided surfaces 18 are in contact with each other. Also in the mold 2 heated to the temperature at the time of tire molding, the divided surfaces 18 are in contact with each other.

  As shown in the enlarged portion of FIG. 3, the dividing surface 18 of the sector shoe 5 has a first surface 20 and a second surface 22. The first surface 20 is a flat surface. The second surface 22 is a flat surface. The contact surface in the dividing surface 18 is the first surface 20. The first surface 20 of the sector shoe 5 is in contact with the first surface 20 of the adjacent sector shoe 5. That is, the first surfaces 20 are in contact with each other. In the mold 2 in the closed state, the second surface 22 is not in contact. For the purpose of making the second surface 22 non-contact, a step is provided at the boundary between the first surface 20 and the second surface 22. In the mold 2 at 25 ° C. and in the closed state, a gap s1 is formed by the second surfaces 22 (see the enlarged portion in FIG. 3). The gap s1 can absorb expansion of the sector shoe 5 due to heat. The gap s1 contributes to improvement of mold accuracy. In the sector shoe 5, the outer side in the radial direction has a larger thermal expansion than the inner side in the radial direction. From the viewpoint of effectively absorbing thermal expansion, the second surface 22 is located on the radially outer side of the first surface 20. That is, the gap s <b> 1 is located on the outer side in the radial direction of the first surface 20. Preferably, a gap s1 is present (remains) in the mold 2 heated to the temperature at the time of tire molding.

  In the closed mold 2, the sector shoe 5 and the side plate 6 are not in contact with each other. In the mold 2 in the closed state, a gap s2 exists between the sector shoe 5 and the side plate 6 (see FIGS. 1 and 2). The gap s2 exists in the mold 2 heated to the temperature at the time of tire molding. Naturally, the gap s2 also exists in the mold 2 at 25 ° C.

  As shown in FIG. 2, a tapered surface 24 is provided on the outer surface of the sector shoe 5. The taper surface 24 has an outer diameter (a distance from the mold axis) that is increased downward. On the other hand, a tapered surface 26 is also provided on the inner peripheral surface of the container 3. As shown in FIG. 2, the tapered surface 26 has an inner diameter that increases toward the lower side. The tapered surface 24 and the tapered surface 26 are in surface contact with each other. The shape of the tapered surface 24 corresponds to the shape of the tapered surface 26.

  As shown in FIG. 3, the container 3 has a slide key 28. The slide key 28 is provided inside the container 3 (tapered surface 26). The slide key 28 is provided along the generatrix of the tapered surface 26. The cross-sectional shape of the slide key 28 is constant at every position in the longitudinal direction. The cross-sectional shape of the slide key 28 is substantially T-shaped.

  The sector shoe 5 has a keyway 30. The key groove 30 is provided on the outer side (tapered surface 24) of the sector shoe 5. The key groove 30 is provided along the generatrix of the tapered surface 24. The longitudinal direction of the keyway 30 is equal to the longitudinal direction of the slide key 28. At every position in the longitudinal direction, the cross-sectional shape of the keyway 30 is constant. The cross-sectional shape of the key groove 30 is substantially T-shaped. The cross-sectional shape of the key groove 30 corresponds to the cross-sectional shape of the slide key 28.

  The slide key 28 is slid into the keyway 30. The slide key 28 and the key groove 30 are engaged with each other. The sector shoe 5 is attached to the container 3 by the engagement between the slide key 28 and the key groove 30. The gap between the slide key 28 and the key groove 30 is very small. The slide key 28 can slide in the keyway 30.

  In the tire manufacturing method using the mold 2, first, a raw cover is obtained by a preforming process. Next, the raw cover is put into the mold 2 while the mold 2 is open and the bladder (not shown) is contracted. At this stage, the rubber composition of the raw cover is in an uncrosslinked state. Next, the mold 2 is closed and the bladder expands. The raw cover is pressed against the cavity surface 10 of the mold 2 by a bladder 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 heating and pressurization. The rubber causes a crosslinking reaction by heating, and a tire is obtained. The process in which the raw cover R is pressurized and heated is referred to as a vulcanization process. In FIG. 3, the raw cover R is not shown.

  The tire obtained through the vulcanization process is taken out from the mold 2. When the tire is taken out, the mold 2 is opened. When the mold 2 is opened, for example, the container 3 moves upward. Due to the movement of the container 3, the sector shoe 5 moves relative to the container 3 downward. This relative movement is achieved by the slide key 28 sliding inside the keyway 30. By this relative movement, the sector shoe 5 moves radially outward. This is because, as described above, the taper surface 24 and the taper surface 26 increase in diameter toward the lower side. As the sector shoes 5 move radially outward, the adjacent sector shoes 5 are separated from each other.

  When the sector shoe 5 moves radially outward, the segment 4 also moves radially outward. Due to the movement of the segments 4 outward in the radial direction, the adjacent segments 4 are separated from each other, and the cavity surface 10 of the segment 4 is separated from the tread surface of the molded tire. Finally, the container 3 and the segment 4 are moved upward, and the molded tire is taken out.

  FIG. 4 is a cross-sectional view for explaining the movement of the segment 4 and the sector shoe 5 when the mold 2 is opened and closed. In FIG. 4, only the segment 4 and the sector shoe 5 are shown. As described above, when the mold 2 in the closed state is opened, the adjacent segments 4 are separated from each other, and the adjacent sector shoes 5 are also separated (see the upward arrow Y1 in FIG. 4). When the opened mold 2 is closed, the reverse movement is performed. That is, in this case, the sector shoe 5 moves relative to the container 3 upward. In other words, the container 3 moves relative to the sector shoe 5 downward. By this relative movement, the sector shoe 5 and the segment 4 move inward in the radial direction. Due to the radially inward movement, the segments 4 that are separated from each other come into contact with each other. Further, the sector shoes 5 that are separated from each other come into contact with each other (see the downward arrow Y2 in FIG. 4).

  The “mold 2 in the closed state” in FIG. 4 indicates the mold 2 heated to the temperature at the time of tire molding. At 25 ° C., the segments 4 are not in contact with each other in the closed mold 2. Although not shown, at 25 ° C., there is a gap sh between the divided surfaces 16 of the segments 4 in the mold 2 in a closed state. On the other hand, the sector shoes 5 are in contact with each other in the mold 2 at 25 ° C. That is, in the mold 2 at 25 ° C. and closed, the divided surfaces 18 (first surfaces 20) are in contact with each other. When the mold 2 is heated to the temperature at which the tire is molded, the segment 4 is thermally expanded and the gap sh disappears. That is, at the temperature at the time of tire molding, the divided surfaces 16 of the segments 4 are in contact with each other in the closed mold 2. Of course, the sector shoes 5 are in contact with each other at the temperature at the time of tire molding. In the mold 2, the linear expansion coefficient of the segment 4 is larger than the linear expansion coefficient of the sector shoe 5.

  Thus, in the mold 2 heated to the temperature at the time of tire molding and closed, not only the divided surfaces 16 of the segments 4 are in contact but also the divided surfaces 18 of the sector shoe 5 are in contact with each other. Yes.

  As described above, in the molding of a tire, a large internal pressure acts due to the expansion of the bladder. The mold 2 is closed by a large pressure so that the mold 2 is not opened by the internal pressure.

  In the conventional mold, the sector shoes 5 are not in contact with each other in the closed mold 2. In the conventional split mold, the contact pressure of the dividing surface is all supported by the dividing surface 16 of the segment 4. In this case, a large contact pressure acts on the segment dividing surface. In the conventional split mold, the load on the segment 4 was large. For this reason, conventionally, the segment 4 has been easily deformed.

  In the mold 2, the contact pressure of the dividing surface is shared by the dividing surface 16 of the segment 4 and the dividing surface 18 of the sector shoe 5. In the mold 2, the load on the segment 4 is reduced. In the mold 2, the deformation of the segment 4 can be suppressed. By suppressing the deformation of the segment 4, the generation of burrs and the deterioration of the roundness are suppressed. With this mold 2, the performance of the molded tire can be improved.

  Further, as described above, in the mold 2, the segments 4 do not contact each other and the sector shoes 5 contact each other at 25 ° C., and the segments 4 contact each other and the sector shoes 5 contact each other at the tire molding temperature. is doing. With this configuration, the contact pressure acting on the dividing surface 16 of the segment 4 can be further reduced, and the deformation of the segment 4 can be effectively suppressed.

  Contact between the segments 4 (dividing surfaces 16) is achieved at the mold temperature during molding. For example, contact between the segments 4 (dividing surfaces 16) is achieved at 200 ° C.

  From the viewpoint of achieving contact between the segments 4 in the mold 2 heated to the temperature at the time of tire molding, in the mold 2 at 25 ° C., the gap SH of the gap sh is preferably 0.5 mm or less, and 0.3 mm or less. Is more preferable. From the viewpoint of reducing the contact pressure acting on the dividing surface 16 of the segment 4, the distance SH is preferably 0.05 mm or more, more preferably 0.1 mm or more, and more preferably 0.2 mm or more.

  FIG. 5 is a plan view showing a part of the tire molding apparatus 40 according to the second embodiment of the present invention. 6 is a cross-sectional view taken along the line VI-VI in FIG. 7 is a cross-sectional view taken along line VII-VII in FIG. FIG. 7 is a cross-sectional view showing a part of the tire molding apparatus 40.

  The tire molding device 40 includes a tire mold 42 and a container 3. Although not shown, the tire molding device 40 further includes a lower plate (base plate), an upper plate, a heating plate, and the like.

  The mold 42 includes a plurality of segments 4, a plurality of sector shoes 44, a pair of upper and lower side plates 6, and a pair of upper and lower bead rings 8.

  A difference between the tire molding device 40 and the tire molding device 1 of the first embodiment is a sector shoe 44. Members other than the sector shoe 44 are common to the tire molding device 40 and the tire molding device 1. The description regarding this common member is abbreviate | omitted suitably below. Regarding the common member, the reference numerals assigned to the tire molding apparatus 1 are used in the drawing of the tire molding apparatus 40.

  The sector shoe 44 is attached to the outer side of the segment 4 in the radial direction. The segment 4 is fixed to the sector shoe 44. Although not shown, the segment 4 is screwed to the sector shoe 44. The plurality of sector shoes 44 are arranged in the circumferential direction via the gap s3. A large number of sector shoes 44 are arranged in a ring shape. Thus, the sector shoe 44 is divided in the circumferential direction. The sector shoe 44 is equally divided in the circumferential direction. All sector shoes 44 are identical.

  The sector shoe 44 is divided into the same number as the segment 4. One segment 4 is attached to one sector shoe 44. The segment 4 and the sector shoe 44 have a one-to-one correspondence. The shape of the inner surface 46 of the sector shoe 44 corresponds to the shape of the outer surface 14 of the segment 4 (see FIG. 6). The inner surface 46 of the sector shoe 44 and the outer surface 14 of the segment 4 are in surface contact. The segment 4 is held by the sector shoe 44.

  5, 6 and 7 show the mold 42 in a closed state. In the mold 42 heated to the temperature at the time of molding the tire and closed, the divided surfaces 16 of the segments 4 are in contact with each other (see FIG. 7). This contact is a surface contact. This contact is substantially a full surface contact. That is, in this contact, the substantially entire surface of the dividing surface 16 and the substantially entire surface of the other dividing surface 16 are in contact.

  In the mold 42 in the closed state, the dividing surface 48 of the sector shoe 44 is not in contact with the dividing surface 48 of another adjacent sector shoe 44. That is, in the mold 42 in the closed state, the divided surfaces 48 are not in contact with each other. A gap s3 exists between the dividing surface 48 of the sector shoe 44 and the dividing surface 48 of another adjacent sector shoe 44 (see FIGS. 5 and 7). The gap s3 can absorb the expansion of the sector shoe 44 due to heat.

  As shown in FIG. 6, a tapered surface 50 is provided on the outer surface of the sector shoe 44. The tapered surface 50 has an outer diameter that increases toward the bottom. On the other hand, a tapered surface 26 is also provided on the inner peripheral surface of the container 3. As shown in FIG. 6, the tapered surface 26 has an inner diameter that increases toward the bottom. The tapered surface 50 and the tapered surface 26 are in surface contact with each other. The shape of the tapered surface 50 corresponds to the shape of the tapered surface 26.

  As shown in FIG. 7, the container 3 has a slide key 28. The slide key 28 is provided inside the container 3 (tapered surface 26). The slide key 28 is provided along the generatrix of the tapered surface 26. The cross-sectional shape of the slide key 28 is constant at every position in the longitudinal direction. The cross-sectional shape of the slide key 28 is substantially T-shaped.

  The sector shoe 44 has a keyway 54. The key groove 54 is provided outside the sector shoe 44 (tapered surface 50). The key groove 54 is provided along the generatrix of the tapered surface 50. The longitudinal direction of the key groove 54 is equal to the longitudinal direction of the slide key 28. At every position in the longitudinal direction, the cross-sectional shape of the key groove 54 is constant. The cross-sectional shape of the key groove 54 is substantially T-shaped. The cross-sectional shape of the key groove 54 corresponds to the cross-sectional shape of the slide key 28.

  The slide key 28 is slid into the key groove 54. The slide key 28 and the key groove 54 are engaged with each other. The sector shoe 44 is attached to the container 3 by the engagement between the slide key 28 and the key groove 54. The gap between the slide key 28 and the key groove 54 is very small. The slide key 28 can slide in the keyway 54.

  The mold 42 opens and closes based on the same principle as the tire molding apparatus 1 described above. That is, the mold 42 opens and closes by the relative movement of the container 3 and the mold 42 in the vertical direction (mold axis direction).

  In the mold 42 in the closed state, the sector shoe 44 and the side plate 6 are in contact (see FIG. 6). The radially inner surface 56 of the sector shoe 44 is in contact with the outer peripheral surface 58 of the side plate 6. This contact is a surface contact. In the mold 42 in the closed state, all the sector shoes 44 are in contact with the side plate 6. Unlike the embodiment of FIG. 2, the gap s2 does not exist in the embodiment of FIG. The contact between the side plate 6 and the sector shoe 44 extends over the entire circumference of the side plate 6.

  The sector shoe 44 and the side plate 6 are in contact with each other in the mold 42 heated to the temperature at the time of tire molding and closed (see FIG. 6). This contact is also achieved in the mold 42 at 25 ° C. That is, the sector shoe 44 and the side plate 6 are in contact with each other in the closed mold 42 at 25 ° C.

  In the conventional mold, the mold 42, the sector shoe 44, and the side plate 6 that are heated and closed at the temperature at the time of tire molding are not in contact with each other. In the conventional split mold, the contact pressure of the dividing surface is all supported by the dividing surface 16 of the segment 4. In the conventional split mold, the load on the segment 4 was large. When the load on the segment 4 is large, the segment 4 is easily deformed.

In the mold 42, the pressure for closing the mold 42 is shared by the following (1) and (2).
(1) Contact pressure between the divided surfaces 16 of the segment 4 (2) Contact pressure between the sector shoe 44 and the side plate 6 In this mold 42, the load on the segment 4 is reduced. In the mold 42, the deformation of the segment 4 can be suppressed. By suppressing the deformation of the segment 4, the generation of burrs and the deterioration of the roundness are suppressed. With this mold 42, the performance of the molded tire can be improved.

  FIG. 7 shows the mold 42 heated to the temperature at the time of tire molding. At 25 ° C., the segments 4 are not in contact with each other in the closed mold 42. Although not shown, at 25 ° C., there is a gap sh between the divided surfaces 16 of the segments 4 in the mold 42 in a closed state. On the other hand, the sector shoe 44 and the side plate 6 are also in contact with the mold 42 at 25 ° C. That is, in the mold 42 at 25 ° C. and closed, the radially inner surface 56 of the sector shoe 44 and the outer peripheral surface 58 of the side plate 6 are in contact with each other. When the mold 42 is heated to the temperature at which the tire is molded, the segment 4 is thermally expanded and the gap sh disappears. That is, at the temperature at which the tire is molded, the divided surfaces 16 of the segments 4 are in contact with each other in the closed mold 42. Of course, the sector shoe 44 and the side plate 6 are in contact with each other at the temperature at the time of tire molding. In the mold 42, the linear expansion coefficient of the segment 4 is larger than the linear expansion coefficient of the sector shoe 44.

  From the viewpoint of achieving contact between the segments 4 in the mold 42 heated to the temperature at the time of tire molding, in the mold 42 at 25 ° C., the gap SH of the gap sh is preferably 0.5 mm or less, and 0.3 mm or less. Is more preferable. From the viewpoint of reducing the contact pressure acting on the dividing surface 16 of the segment 4, the distance SH is preferably 0.05 mm or more, more preferably 0.1 mm or more, and more preferably 0.2 mm or more.

  In the first embodiment, the sector shoe 5 is in contact with another sector shoe 5 and in contact with the side plate 6 in the mold 2 heated to the temperature at the time of molding the tire and closed. Not done. On the other hand, in the second embodiment, the sector shoe 44 is in contact with the side plate 6 in the mold 42 that is heated to the temperature at the time of tire molding and is closed, and other sectors. There is no contact with the shoe 44. Further, from the viewpoint of distributing pressure, in the mold heated to the temperature at the time of molding the tire and closed, the sector shoe is in contact with another sector shoe, and the sector shoe is in contact with the side plate. Also possible are configurations.

  The material of the segment is not limited. Since the present invention suppresses the deformation of the segment, it is particularly effective when the material is easily deformed. From this viewpoint, the material of the segment is preferably an aluminum alloy or aluminum. Aluminum alloy or aluminum is easy to cast and process. Aluminum alloy or aluminum is lightweight and easy to handle in a factory.

  The material of the sector shoe is not limited. From the viewpoint of improving the mold accuracy and suppressing the generation of burrs on the divided surfaces, the material of the sector shoe preferably has a smaller linear expansion coefficient than the material of the segment. From this viewpoint, the material of the sector shoe is preferably steel. Steel is less likely to be deformed than aluminum alloys, and can contribute to improved mold accuracy.

  In the present invention, the shape of the sector shoe is not limited.

  The present invention is applicable to existing molds. By exchanging only the sector shoe of the existing mold, the present invention can be applied to the existing mold. The present invention is highly versatile.

Example 1
As Example 1, constituent members of a tire molding apparatus having the same structure as the tire molding apparatus 1 of the first embodiment described above were produced. The mold had a 9-part structure having 9 segments. The size of the tire molded by the mold was 205 / 65R15. The material of the sector shoe was steel. The material of the segment was an aluminum alloy. On the divided surface of the sector shoe, the step between the first surface (contact surface) and the second surface (non-contact surface) was 0.5 mm. The interval SH was an average value of 9 places and was 0.2 mm. That is, in the mold of Example 1, the segment split surfaces were not in contact with each other in the closed state at 25 ° C. In the closed state at 25 ° C., the divided surfaces of the sector shoes were in contact with each other. When heated to the temperature at the time of tire molding (190 ° C.), the divided surfaces of the segments also contacted each other. Using this mold, a tire was molded by the manufacturing method described above. The molded tires were evaluated. The evaluation results are shown in Table 1 below.

(Example 2)
As Example 2, a component member of a tire molding apparatus having the same structure as the tire molding apparatus 40 of the second embodiment described above was produced. The mold had a 9-part structure having 9 segments. The size of the tire molded by the mold was 205 / 65R15. The material of the sector shoe was steel. The material of the segment was an aluminum alloy. The interval SH was set to 0.2 mm. That is, in the mold of Example 2, the segment split surfaces were not in contact with each other in the closed state at 25 ° C. In the closed state at 25 ° C., the sector shoe and the side plate were in contact with each other. When heated to the temperature at the time of tire molding (190 ° C.), the divided surfaces of the segments also contacted each other. A tire was molded in the same manner as in Example 1 except that this mold was used. The molded tires were evaluated. The evaluation results are shown in Table 1 below.

(Comparative example)
A mold of a comparative example was obtained in the same manner as in Example 1 except that the interval between the divided surfaces of the sector shoe was 18 mm. In the mold of this comparative example, the divided surfaces of the sector shoes were not in contact with each other in a state where the mold was heated and closed at the time of tire molding. In the mold of this comparative example, the sector shoe and the side plate were not in contact with each other when the mold was heated to the temperature at the time of tire molding and was closed. A tire was molded in the same manner as in Example 1 except that this mold was used. The molded tires were evaluated. The evaluation results are shown in Table 1 below.

  The evaluation items were “roundness” and “burr thickness”. The evaluation method for each item is as follows.

[Evaluation of roundness]
The segment removed from the container was attached to a measuring instrument having the same inner diameter as the inner surface of the sector shoe (the inner surface 46), and the displacement (mm) of the inner diameter at the tread center point was measured with a laser displacement meter. The evaluation results are shown in Table 1 below.

[Burr thickness T1]
The thickness T1 of the burr generated on the segment dividing surface was evaluated. The burr generated on the tire was visually confirmed, and the thickness was measured with a caliper. The maximum value of the burr thickness was measured at each of the divided surface positions (9 locations), and the maximum value of these nine data was defined as the thickness T1 (mm). The evaluation results are shown in Table 1 below.

  3000 tires were continuously molded by each mold. The first tire and the 3000th tire were evaluated. The evaluation results are shown in Table 1 below.

  From the results shown in Table 1, the advantages of the present invention are clear.

FIG. 1 is a plan view showing a part of the tire molding apparatus according to the first embodiment of the present invention. FIG. 2 is a cross-sectional view taken along line II-II in FIG. FIG. 3 is a cross-sectional view taken along line III-III in FIG. FIG. 4 is a view for explaining the movement of the segment and the sector shoe when the mold is opened and closed. FIG. 5 is a plan view showing a part of the tire molding apparatus according to the second embodiment of the present invention. 6 is a cross-sectional view taken along line VI-VI in FIG. 7 is a cross-sectional view taken along line VII-VII in FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1, 40 ... Tire molding apparatus 2, 42 ... Tire mold 3 ... Container 4 ... Segment 5, 44 ... Sector shoe 6 ... Side plate 8 ... Bead ring 10. ..Cavity surface 16: Segment division surface 18, 48 ... Sector shoe division surface 20 ... First surface (contact surface)
22 ... Second surface (non-contact surface)
24, 50 ... Tapered surface of the sector shoe 26 ... Tapered surface of the container 28 ... Slide key 30 ... Key groove s1, s2, s3 ... Gap

Claims (3)

A plurality of segments arranged in the circumferential direction, a plurality of sector shoes arranged in the circumferential direction, and a side plate,
Each of the sector shoes is attached to each of the segments,
In the state where the mold is closed, the split surfaces of the segments are in contact with each other,
A tire mold in which the sector shoe is in contact with another sector shoe or a side plate in a state where the mold is closed.   The tire mold according to claim 1, wherein the divided surfaces of the sector shoes are in contact with each other when the mold is closed.   The tire mold according to claim 1, wherein the sector shoe is in contact with the side plate when the mold is closed.

Images