JP4915201B2 - Method and apparatus for vulcanizing pneumatic tires - Google Patents

Description

  The present invention relates to a method and an apparatus for vulcanizing a pneumatic tire. More specifically, the present invention relates to a pneumatic tire that can be used for a long period of time without damaging by reducing the degree of bending of the bladder and preventing stress concentration due to bending. The present invention relates to a vulcanization method and apparatus.

  Conventionally, a bagwell type vertical vulcanizing apparatus is known in which a bladder is housed in a bagwell when a tire after vulcanization is taken out (see, for example, Patent Document 1). In such a bagwell type vulcanizing apparatus, as illustrated in FIG. 5 of Patent Document 1, the upper clamp member to which the upper end portion of the bladder is attached is moved to a certain position inside the bagwell formed inside the cylindrical body. In order to move, the bladder is folded small inside the bagwell, and a large bending stress is generated in the bent portion. There was a problem that once the bent portion was bent, the stress was concentrated as the bent portion, and cracks occurred due to repeated bending, resulting in early breakage. Further, when the bending wrinkle of the bending portion of the bladder becomes prominent, the bending wrinkle is transferred to the inside of the vulcanized tire, which may adversely affect the appearance.

Also, when the bladder is housed inside the bagwell, the bladder is caught between the upper clamp member and the lower mold bead ring or the cylindrical body, or the bladder is in sliding contact with the lower mold bead ring or the cylindrical body. There was a problem of damage due to wear or the like.
JP 2002-205308 A

  An object of the present invention is to provide a method and an apparatus for vulcanizing a pneumatic tire that can be used for a long period of time without breakage by relaxing the bending degree of the bladder and preventing stress concentration due to bending.

In order to achieve the above object, the pneumatic tire vulcanizing method of the present invention attaches the lower end portion of the bladder to a lower clamp member disposed below the lower bead ring, and the center post moves up and down. attached to fixed upper clamp member, the vulcanizing method of a pneumatic tire vulcanizing the green tire in the mold interior to protrude the bladder from Bagwell inflate inside the green tire, vulcanizing the green tire After vulcanization, when the inflated bladder is contracted and the vulcanized tire is taken out upward, the upper clamp member can be moved downward to expand and contract in the vertical direction disposed below the upper clamp member. The upper end of the bladder attached to the upper clamp member while restricting the downward movement by a flexible stretchable spacer is It is characterized in that so as to be positioned upward from the upper surface of the lower mold bead ring.

Further, the pneumatic tire vulcanizing apparatus of the present invention has an upper side fixed to a center post that moves the upper end portion up and down while attaching the lower end portion of the bladder to a lower clamp member disposed below the lower bead ring. A pneumatic tire vulcanizing device that is attached to a clamp member and can be inflated inside a green tire inside the mold by allowing the bladder to protrude from the bag well, and can be expanded and contracted vertically below the upper clamp member. An elastic spacer is arranged, and the downward movement of the upper clamp member is regulated by the elastic spacer, and the lowermost position of movement of the upper end portion of the bladder attached to the upper clamp member is set to the upper surface of the lower bead ring. It is characterized by being configured to be further upward.

According to the present invention, the lower end portion of the bladder is attached to the lower clamp member disposed below the lower bead ring, and the upper end portion is attached to the upper clamp member fixed to the center post that moves up and down. After projecting from bagwell and inflating inside the green tire and vulcanizing the green tire inside the mold, the upper clamp member The upper end of the bladder can be positioned above the upper surface of the lower bead ring by restricting the downward movement by an elastic spacer that can be expanded and contracted in the vertical direction arranged below the upper clamp member. The radius of curvature of the bent portion becomes larger, and the bending condition can be relaxed. At the same time, it is possible to avoid biting and sliding contact between the upper clamp member of the bladder and the lower mold bead ring or the cylindrical body.

  Also, the upper end of the bladder, whose downward movement is restricted by the stretchable spacer, can be changed in the vertical direction within the range of the stretchable width of the stretchable spacer, so it can be dispersed without fixing the bent part. It is possible to prevent stress concentration from occurring at a specific portion of the bladder. In this way, the burden due to bending of the bladder is reduced, so that early breakage can be prevented and long-term use is possible.

  Hereinafter, a method and an apparatus for vulcanizing a pneumatic tire according to the present invention will be described based on the embodiments shown in the drawings.

  As illustrated in FIG. 1, a central mechanism 3 of a pneumatic tire vulcanizing apparatus 1 (hereinafter referred to as a vulcanizing apparatus 1) according to the present invention has a lifting post 6 on the inner peripheral side of a cylindrical body 7. A support sleeve 6 a is fixed to the center upper portion of the post 6. A center post 4 is provided through which the support sleeve 6a and the lifting post 6 are inserted vertically. The elevating post 6 has a fluid passage 8 penetrating vertically, and a lower clamp member 13 b is disposed so as to face the inner peripheral surface of the cylindrical body 7. Further, a lower bead ring 12 b is fixed to the upper end portion of the cylindrical body 7. The elevating post 6, the support sleeve 6a, the lower clamp member 13b, the cylindrical body 7 and the lower bead ring 12b are configured to be integrally movable up and down, and the center post 4 is independently movable up and down independently of these. It is configured.

  A steel coil spring 5a placed on the support sleeve 6a is extrapolated to the center post 4, and an upper clamp member 13a having a disk-like upper and lower divided structure is fixed to the upper end portion of the center post 4. . The upper end of the bladder 2 is attached to the upper clamp member 13a, and the lower end of the bladder 2 is attached to the lower clamp member 13b.

  A lower heating plate 10b is disposed on the outer peripheral side of the cylindrical body 7, and a lower mold 9b is installed on the lower heating plate 10b. A lower die bead ring 12b is arranged at a predetermined position on the upper inner periphery of the lower die 9b.

  An upper mold 9a is arranged facing the lower mold 9b, and a bolster plate 11 is fixed to the upper side of the upper mold 9a via an upper heating plate 10a. The upper mold 9a, the upper heating plate 10a, and the bolster plate 11 are configured to integrally move up and down by raising and lowering an elevating member 11a connected to the bolster plate 11. An upper bead ring 12a is installed at a predetermined position on the lower inner periphery of the upper mold 9a.

  In FIG. 1, a green tire 14 in which the elevating member 11 a is lowered and the upper mold 9 a and the lower mold 9 b are assembled and the upper and lower bead portions 15 a and 15 b are set on the upper bead ring 12 a and the lower bead ring 12 b. The upper mold 9a and the lower mold 9b are pressed and vulcanized by the bladder 2 inflated by the heated pressurized fluid supplied from the supply flow path 8.

Hereinafter, the vulcanization method of the present invention using the vulcanizer 1 will be described.
After the vulcanization of the green tire 14 illustrated in FIG. 1 is completed, the elevating member 11a is raised and the upper mold 9a, the upper heating plate 10a, and the bolster plate 11 are integrally moved up and down to be illustrated in FIG. Then, the lower mold 9b is opened so that the vulcanized tire 14a can be taken out upward.

  Next, as illustrated in FIG. 3, the pressurized fluid inside the bladder 2 is discharged from a discharge channel (not shown) and the inflated bladder 2 is contracted. Further, the center post 4 is lowered to move the upper end of the bladder 2 downward. However, in the present invention, the upper clamp member 13a that moves downward is brought into contact with the coil spring 5a and the downward movement is restricted. It is comprised so that it may become a position above the upper surface of the lower mold bead ring 12b.

  As described above, the upper end of the bladder 2 does not move down to the inside of the bag well 7a formed inside the cylindrical body 7, so that the radius of curvature of the bent portion of the bladder 2 becomes larger than before and the bending condition is eased. , Bending stress is reduced and cracks are less likely to occur. Therefore, it is possible to prevent the bladder 2 from being damaged early and to use the bladder 2 for a long time. Along with this, deep bending wrinkles are less likely to occur in the bladder 2, so that a problem that the bending wrinkles are transferred to the inside of the vulcanized tire 14a and the appearance is deteriorated can be prevented.

  Thus, the lowermost position of movement of the upper end portion of the bladder 2 is higher than the upper surface of the lower bead ring 12b, so that the upper clamp member 13a and the lower bead ring 12b or the cylindrical body 7 are interposed between them. It can also be prevented that the bladder 2 is bitten, or the bladder 2 is slidably contacted with the lower mold bead ring 12b or the cylindrical body 7 and is damaged due to wear or the like.

  Here, it is preferable that the clearance C between the upper end portion of the bladder 2 at the lowermost movement position and the upper surface of the lower bead ring 12b is, for example, not less than 1 cm and not more than 7 cm. When the clearance C is 1 cm or more, the bending state of the bladder 2 can be sufficiently relaxed. In addition, when the clearance C is 7 cm or less, the vertical clearance h between the bead portion 15a on the upper side of the vulcanized tire 14a and the top portion of the bent bladder 2 can be sufficiently secured. For this reason, it is possible to prevent a problem that the transfer hook for taking out the vulcanized tire 14a is brought into contact with the bladder 2 and is damaged when the transfer hook is hooked on the bead portion 15a. For example, the clearance h is preferably 6 cm or more.

  Furthermore, since the position of the upper end portion of the bladder 2 can be changed in the vertical direction within the range of the expansion / contraction width in the vertical direction of the coil spring 5a, the bent portion can be dispersed without being fixed at a specific location. Thereby, it can prevent that stress concentration arises in the specific location of the bladder 2, and it becomes difficult to damage the bladder 2 further, and it can aim at lifetime improvement.

  As described above, since the upper clamp member 13a in which the vertical movement is restricted can move up and down within the range of the expansion and contraction width of the coil spring 5a, even when the mold to be installed is replaced with a small mold, The upper mold 9a and the lower mold 9b can be assembled as long as the coil spring 5a is within an allowable range. Therefore, it is not necessary to perform extra work such as exchanging the coil spring 5a every time the mold is changed, and the vulcanization operation can be performed as it is.

  In the above embodiment, the coil spring 5a is illustrated. However, the present invention is not limited to this, and the bladder 2 can be expanded and contracted in the axial direction (vertical direction) of the center post 4 and the downward movement of the upper clamp member 13a is restricted. It is possible to employ a stretchable spacer whose upper end can be positioned above the upper surface of the lower bead ring 12b.

  For example, as illustrated in FIG. 4, the coil spring 5 a may be erected on the upper surface of the support sleeve 6 a without being extrapolated to the center post 4 and arranged around the center post 4. Further, as illustrated in FIG. 5, a leaf spring-like spacer 5 b that bends on the upper surface of the support sleeve 6 a may be erected and arranged around the center post 4.

  The stretchable spacers such as the coil spring 5a and the leaf spring spacer 5b may be provided between the upper clamp member 13a and the support sleeve 6a. For example, the coil spring 5 is fixed to the lower surface of the upper clamp member 13a. You can also.

  Further, since the stretchable spacer is exposed to a pressurized heating fluid such as steam supplied from the supply flow path 8, the surface is preferably subjected to a rust prevention treatment or formed of a rust prevention material such as stainless steel.

  The air of the same specification of tire size 155 / 65R13 using the vulcanizing apparatus of the present invention having the same structure illustrated in FIG. 1 and the conventional vulcanizing apparatus with the coil spring removed from the center post of the vulcanizing apparatus of the present invention. The tires vulcanized and the number of tires that could be vulcanized before the bladder was damaged were measured, and the results are shown in Table 1. In the vulcanizing apparatus (Example) of the present invention, when the vulcanized tire was taken out of the mold, the upper end portion of the contracted bladder was moved downward to a position about 5 cm above the upper surface of the lower bead ring. In the conventional vulcanizing apparatus (conventional example), the upper end portion of the bladder contracted when the vulcanized tire is taken out from the mold is moved downward to the inside of the bag well so as to be positioned 13 cm below the embodiment.

  From the results in Table 1, it can be seen that according to the vulcanization method and vulcanizer of the present invention, the bladder can be prevented from being damaged more than the conventional vulcanization method and vulcanizer and can be used for a long time.

It is a longitudinal half sectional view which illustrates the vulcanizing device of the pneumatic tire of the present invention. In the vulcanization method of the pneumatic tire of the present invention, it is a longitudinal half sectional view which illustrates the state where the upper mold was moved upward and the lower mold was opened. 3 is a longitudinal half section illustrating the next state of FIG. 2. It is a longitudinal half sectional view showing a modification of the coil spring of FIG. It is a longitudinal half sectional view which shows another modification of the coil spring of FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Pneumatic tire manufacturing apparatus 2 Bladder 3 Center mechanism 4 Center post 5a Coil spring 5b Leaf spring-like spacer 6 Lifting post 6a Support sleeve 7 Cylindrical body 7a Bagwell 8 Supply flow path 9a Upper mold 9b Lower mold 10a Upper heating plate 10b Lower heating plate 11 Bolster plate 11a Lifting member 12a Upper die bead ring 12b Lower die bead ring 13a Upper clamp member 13b Lower clamp member 14 Green tire 14a Vulcanized tire 15a, 15b Bead portion

Claims (7)

It is attached to the lower clamp member and a lower end disposed below the lower mold bead ring of the bladder, attached to the upper clamp member fixed to the center post to vertically move the upper portion, to project the bladder from Bagwell Green In a method of vulcanizing a pneumatic tire in which the green tire is vulcanized inside a mold by inflating the inside of the tire, the vulcanized by shrinking the inflated bladder after vulcanizing the green tire. When the tire is taken out upward, the upper clamp member is moved downward and the downward movement is restricted by an elastic spacer that is arranged below the upper clamp member and can be expanded and contracted vertically. An empty space in which the upper end of the attached bladder is positioned above the upper surface of the lower bead ring. Vulcanizing method of tire enters.   The method for vulcanizing a pneumatic tire according to claim 1, wherein the stretchable spacer is a coil spring extrapolated to the center post.   The upper end portion of the bladder attached to the upper clamp member, the downward movement of which is restricted by the stretchable spacer, is positioned in the range of 1 cm to 7 cm above the upper surface of the lower bead ring. 2. A method for vulcanizing a pneumatic tire according to 2. It is attached to the lower clamp member and a lower end disposed below the lower mold bead ring of the bladder, attached to the upper clamp member fixed to the center post to vertically move the upper portion, and enables protruding the bladder from Bagwell In a pneumatic tire vulcanizing apparatus configured to inflate inside a green tire inside a mold, a stretchable spacer that is vertically stretchable is disposed below the upper clamp member, and the stretchable spacer allows the Vulcanization of a pneumatic tire configured to regulate the lower movement of the upper clamp member so that the lowermost movement position of the upper end portion of the bladder attached to the upper clamp member is above the upper surface of the lower bead ring apparatus. The pneumatic tire vulcanizing apparatus according to claim 4, wherein the stretchable spacer is a coil spring and is configured to be extrapolated to the center post.   The vulcanization of a pneumatic tire according to claim 4 or 5, wherein a lowermost position of movement of the upper end portion of the bladder attached to the upper clamp member is set in a range of 1 cm to 7 cm above the upper surface of the lower bead ring. apparatus.   The vulcanizing apparatus for a pneumatic tire according to any one of claims 4 to 6, wherein the stretchable spacer is made of a rust preventive material or the surface thereof is subjected to a rust preventive treatment.

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