JP6660136B2 - Tire vulcanizing mold and tire manufacturing method - Google Patents

Description

  The present invention relates to a tire vulcanizing mold and a tire manufacturing method using the tire vulcanizing mold.

  Conventionally, as a tire vulcanizing mold, when a vent hole communicating a tread molding surface (inner surface) and a back surface (outer surface) of a sector overlaps a mounting hole for screwing a mounting screw, a cylinder of the mounting screw is used. There is known a structure in which a communication hole extending in an axial direction is provided to discharge a gas generated during vulcanization molding to the outside from a vent hole through the communication hole (for example, see Patent Document 1).

  However, in the conventional tire vulcanizing mold, a communication hole for venting gas is formed on the outer surface of the mounting screw. For this reason, there is a problem that the support strength of the mounting screw is reduced and the support state of the sector is not stable. Processing of the mounting screw on the outer surface is troublesome and time-consuming due to the shape of the screw, and there is a problem in terms of productivity. Further, the sector is changed due to a difference in the tread surface of the tire or the like, but it is actually difficult to screw a mounting screw having a processed outer surface into practice, and there is a problem in terms of interchangeability.

JP 2008-221586 A

  The present invention provides a tire vulcanizing mold capable of realizing effective degassing without lowering the support strength of the mounting screw and lowering the productivity, or deteriorating the removability to the sector. And a tire manufacturing method.

The present invention, as means for solving the above problems,
A tire vulcanizing mold having a plurality of annular sectors arranged side by side in the circumferential direction,
Each of the sectors communicates the inner surface constituting the tread molding surface, the outer surface located on the radially opposite side to the inner surface , the mounting hole formed in the outer surface, and the inner surface and the mounting hole. has a vent hole, the,
A segment that supports the sector from the outer surface side and has a fastening hole formed concentrically with the axis of the mounting hole;
Wherein are screwed into the mounting hole, and the intermediate member that having a female screw portion on the inner diameter portion,
Through the clamping hole from the segment side, and the screwed into the female threaded portion of the intermediate member, the bolt having a through hole extending in axial direction are formed,
The present invention provides a tire vulcanizing mold characterized by comprising:

  With this configuration, at the time of vulcanization molding, the residual gas passes through the mounting hole from the vent hole and is discharged through the through hole formed in the bolt. Since this bolt has a simple configuration in which only a through hole is formed, it can be easily processed. In addition, since special processing is not required for the male screw portion of the bolt, the supporting state of the sector by the bolt can be made strong and stable. Of course, workability when screwing or removing the bolt is not hindered.

  It is preferable that the intermediate member is attached with a gap between the intermediate member and a bottom surface of the attachment hole.

  With this configuration, the residual gas that has entered the mounting hole via the vent hole can flow to the through hole opened at the tip of the bolt without being obstructed by the intermediate member.

  It is preferable that, in a state where the intermediate member is screwed into the mounting hole, a position of a tip of the bolt screwed to the intermediate member is away from a bottom surface of the mounting hole.

  With this configuration, the residual gas that has flowed into the intermediate member can be guided to the outside through the through hole formed in the bolt.

  It is preferable that the intermediate member has a cutout groove extending from one end face in contact with the bottom surface of the mounting hole toward the other end side, and communicating an inner surface and an outer surface.

  With this configuration, it is possible to secure a route for reliably discharging the residual gas through the notch groove regardless of the screw position of the intermediate member.

  It is preferable that the sector has a spring vent disposed on an inner surface where the vent hole is opened.

  With this configuration, the residual gas can be exhausted by opening the spring vent until immediately before the mold clamping is completed, and after the mold clamping is completed, the spring vent can be closed to prevent the rubber from flowing out.

Further, the present invention provides, as means for solving the above problems,
Using the tire vulcanizing mold, a tire manufacturing method for vulcanizing a green tire,
During clamping, the internal gas through the vent hole from the inner surface side of said sector to flow into the mounting hole, in the axial direction of the bolt screwed to the intermediate member to be screwed into the mounting hole provides a tire manufacturing method characterized by discharging to the outside of the sector through the through-hole extending.

  ADVANTAGE OF THE INVENTION According to this invention, a residual gas can be discharged | emitted through the through-hole formed in the bolt. The bolt has only a through hole and can be easily processed. Since the male screw portion of the bolt is not processed at all, the supporting state of the sector can be made strong and stable, and there is no problem in screwing and removing the bolt.

FIG. 1 is a front half sectional view showing a part of a vulcanization molding machine equipped with a tire vulcanization mold according to the present embodiment. FIG. 2 is a front half sectional view showing a mold clamping operation of the tire vulcanizing mold of FIG. 1. FIG. 2 is an exploded perspective view showing a sector and a segment of FIG. 1. FIG. 4 is a partial plan sectional view of the sector of FIG. 3. It is sectional drawing of the vent plug of FIG. FIG. 4 is a perspective view of the bolt of FIG. 3. FIG. 4 is a perspective view of the insert of FIG. 3. FIG. 2 is a partial development view of a tire obtained by being vulcanized and molded by the tire vulcanizing mold shown in FIG. 1.

  Hereinafter, embodiments according to the present invention will be described with reference to the accompanying drawings. Note that the following description is merely an example in nature, and is not intended to limit the present invention, its application, or its use. Also, the drawings are schematic, and the ratios of the respective dimensions and the like are different from actual ones.

  FIG. 1 shows a state in which a tire vulcanizing mold 2 according to the present embodiment is mounted on a vulcanizing molding machine 1. A tire vulcanizing mold 2 is mounted via a container 6 between an upper plate 3 and an upper platen 4 of the vulcanizing molding machine 1 and a lower platen 5.

  The upper plate 3 is fixed to the lower end of the lifting cylinder 7. A lifting rod 8 is disposed at the center of the lifting cylinder 7. The upper platen 4 is fixed to the lower end of the lifting rod 8. The lifting cylinder 7 and the lifting rod 8 are raised and lowered by a drive mechanism (not shown). However, the upper plate 3 and the upper platen 4 are configured to be able to move up and down independently. A flow path 4a is formed in the upper platen 4 so that the temperature can be adjusted by flowing a heat exchange medium (for example, oil).

  The lower platen 5 is formed with a flow path 5 a through which the heat exchange medium flows, similarly to the upper platen 4. Then, by adjusting the temperature of the heat exchange medium, the tire vulcanizing mold 2 can be set to a desired vulcanizing temperature via the upper platen 4 and the lower platen 5. A bladder unit 9 is arranged at the center of the lower platen 5.

  The bladder unit 9 is configured by attaching a bladder 13 to an upper clamp 11 and a lower clamp 12 fixed to a vertically movable support shaft 10. Air is supplied and discharged into and from a space surrounded by the upper clamp 11, the lower clamp 12, and the bladder 13 by a supply / exhaust device (not shown). The bladder is supplied with air and inflated to the outer peripheral side to support the green tire from the inside.

  The container 6 includes a segment 14, a jacket ring 15, an upper container plate 16, and a lower container plate 17.

  The segment 14 is composed of a plurality (here, seven) for screwing each sector 20 of the tire vulcanizing mold 2 described later. The inner surface of each segment 14 is along the outer surface 20b of the sector 20, and the outer surface is constituted by an inclined surface (outer peripheral conical surface 14a) that gradually expands toward the outer diameter side as it goes downward. Each segment 14 is supported by an upper slide 18 so as to be able to reciprocate in the radial direction.

  The jacket ring 15 has a hollow cylindrical shape and has an upper end surface fixed to the upper plate 3. And it goes up and down according to the up / down operation of the up / down cylinder 7. The inner surface of the jacket ring 15 is constituted by an inner peripheral side conical surface 15a that is gradually inclined toward the outer diameter side toward the lower end side. The inner conical surface of the jacket ring 15 and the outer conical surface of each segment 14 slide along the conical surfaces so that they do not separate from each other (for example, by a configuration such as a tenon and a dovetail groove). I have. Accordingly, when the jacket ring 15 descends, the inner peripheral conical surface 15a presses the outer peripheral conical surface 14a of each of the segments 14, and the segment 14 that has spread to the outer diameter side is annularly formed on the inner diameter side. It can be moved to a continuous state.

  The upper slide 18 is fixed to the outer peripheral lower surface of the upper container plate 16, and an upper mold 21 described later is fixed to the inner peripheral lower surface. The upper container plate itself is fixed to the lower surface of the upper platen 4. As a result, when the lifting rod 8 moves up and down, the upper die 21 and the segment 14 (including the sector 20 fixed to the segment 14) move up and down together with the upper platen 4 and the upper container plate 16.

  In the lower container plate 17, a lower slide 19 is fixed to an upper surface on an outer peripheral side, and a lower mold 22 described later is fixed to an upper surface on an inner peripheral side. The segment 14 is placed on the lower slide 19 at the time of mold clamping, and is supported so as to be slidable in the radial direction. The lower container plate itself is fixed to the upper surface of the lower platen 5.

  The tire vulcanizing mold 2 includes a sector 20, an upper mold 21, and a lower mold 22.

  The sector 20 is made of an aluminum alloy, is divided into a plurality of parts in the circumferential direction of the tire (here, divided into seven parts), and is connected in an annular shape while moving to the inner diameter side. Each sector 20 has an inner surface 20a formed of a tread forming surface for forming a tread portion of a tire.

  As shown in FIG. 4, a plurality of vent holes 23 communicating the inner surface 20a and the outer surface 20b are formed in each sector 20. In each of the vent holes 23, a vent plug 24 is mounted on the inner surface side. As shown in FIG. 5, the vent plug 24 includes a cylindrical housing 25 fitted into the vent hole 23, a stem 26 inserted into the housing 25 to open and close a passage, and the stem 26 from the inner surface 20a. And a spring 27 for urging to protrude.

  As shown in FIG. 3, a plurality of mounting holes 28 for fixing to the segment 14 are formed on the outer surface 20 b of each sector 20. A female screw is formed in the mounting hole 28, and an insert 29 is mounted therein. The insert 29 is made of a material having a higher hardness than the sector 20, such as stainless steel. As shown in FIG. 7, the insert 29 has a male screw 29a formed on the outer periphery thereof to be screwed into the female screw of the mounting hole 28, and a female screw 29b formed on the inner periphery. The insert 29 has a cutout groove 29c at one end. The cutout groove 29c is formed of a pair of cutouts extending in the axial direction from one end of the insert 29, and the cutouts are arranged symmetrically with respect to the axial center of the insert 29.

  A bolt 30 for fixing to the segment 14 is screwed into the female screw 29 b of the ENZERT 29. When the bolt 30 is screwed into the insert 29 mounted on the mounting hole 28, a gap is formed between the tip surface of the bolt 30 and the bottom surface of the mounting hole 28. As shown in FIG. 6, the bolt 30 is formed with a center hole 30a that communicates the distal end face with the head. The processing of the center hole 30a can be easily performed with a drill or the like. In addition, since there is no processing of the male screw of the bolt 30, damage to the male screw due to this processing is unlikely to occur, and problems such as difficulty in screwing into the insert 29 due to the damage hardly occur.

  As shown in FIG. 4, a vent hole 23 communicates with each mounting hole 28. As a result, the air in the tire vulcanizing mold 2 flows into the mounting hole 28 through the vent hole 23, and from the center hole 30 a of the bolt 30 through the cutout groove 29 c of the insert 29. Flows to the segment side. Then, the air is discharged to the outside of the tire vulcanizing mold 2 through a gas vent groove (not shown) formed in the segment 14. At the time of mold clamping, the space surrounded by the upper plate 3, the jacket ring 15, and the lower container plate 17 where the tire vulcanizing mold 2 is disposed is appropriately sealed with an O-ring or the like at necessary places. Sealed. This sealed space is evacuated by a vacuum pump or the like (not shown). Thereby, the residual gas in the tire vulcanizing mold is easily discharged to the closed space. The vent hole 23 communicates with the mounting hole 28 and, for example, with respect to a plurality of blocks B formed on the tread portion of the tire T after vulcanization molding as shown by a two-dot chain line in FIG. Are formed at a plurality of locations.

  Both side surfaces of each sector 20 are constituted by contact surfaces 20c in which the inner diameter side is in contact with adjacent sectors, and the outer diameter side is constituted by a relief surface 20d which forms a gap.

  As shown in FIG. 1, the upper die 21 is formed in an annular shape, and an upper bead ring 31 is fixed to an inner peripheral portion. The upper mold 21 is fixed to the upper container plate 16 and moves up and down as the lifting rod 8 moves up and down. When descending, the upper bead ring 31 can press the bead portion of the green tire GT. Thereby, a sidewall portion and a bead portion of the tire are formed by the lower inner surface of the upper die 21 and the lower surface of the upper bead ring 31.

  The lower mold 22 is formed in an annular shape similarly to the upper mold 21, and a lower bead ring 32 is fixed to an inner peripheral portion.

  In the vulcanization molding machine 1 equipped with the tire vulcanization mold 2 having the above-described configuration, mold clamping is performed as follows, and vulcanization molding of the green tire GT is performed.

  In other words, the green tire GT is placed on the lower mold 22 with the axial direction of the green tire GT being up and down in the mold open state shown in FIG. At this time, the lower bead portion is positioned on the lower bead ring 32. As shown in FIG. 2B, air is supplied into the bladder 13 to inflate the bladder 13, and the outer surface thereof holds the inner surface of the green tire GT. As a result, the green tire GT is supported by the lower bead ring 32 and the bladder 13 and is in a non-contact state with the lower mold 22.

  Then, by driving a driving device (not shown), the lifting rod 8 and the lifting cylinder 7 are lowered, and the mold clamping operation is started. Thereby, first, as shown in FIG. 2C, the upper bead ring 31 comes into contact with a bead portion located above the green tire GT. Then, as shown in FIG. 2D, after the green tire is deformed via the bead portion, the upper die 21 contacts the green tire GT.

  Subsequently, the lowering operation of the upper mold 21 is temporarily stopped at a predetermined position from the time when the upper mold 21 contacts the green tire GT to the position where the mold clamping is completed. Further, by lowering the upper mold 21 to the mold clamping completion position, the green tire GT is held between the upper mold 21 and the lower mold 22 as shown in FIG.

  Even after the upper mold 21 has descended to the mold clamping completion position, the descending movement by the elevating cylinder 7 continues, and the jacket ring 15 moves downward together with the upper plate 3. The inner conical surface of the jacket ring 15 presses the outer conical surface of the segment 14. As a result, the sector 20 fixed to the segment 14 moves to the inner diameter side.

  When the inner surface of the sector 20 comes into contact with the outer surface of the green tire GT, the lowering of the lifting cylinder 7 is temporarily stopped, and then the upper plate 3 is lowered until it comes into contact with the upper platen 4. As a result, the outer side of the green tire GT is pressed by the upper mold 21, the lower mold 22, and the sector 20, and the inner side is pressed by the bladder 13, as shown in FIG. In the upper platen 4 and the lower platen 5, a heat exchange medium temperature-controlled so that the green tire GT can be vulcanized at a predetermined vulcanization temperature (regardless of the mold opening state and the mold clamping state) at all times. are doing. Thereby, the green tire GT is vulcanized and molded, and the tire is completed.

  At this time, the residual air on the inner surface side of the sector 20 is exhausted through the vent hole 23. That is, in the vent plug 24 attached to the vent hole 23, the stem 26 is initially in a state of protruding from the housing to open the passage. The vent hole 23 communicates with the mounting hole 28. An insert 29 is screwed into the mounting hole 28, and a cutout groove 29c is formed in the insert 29. A gap is formed between the bolt 30 screwed to the insert 29 and the bottom surface of the mounting hole 28. Further, the closed space of the vulcanization molding machine is connected to a vacuum pump. For this reason, the residual air in the tire vulcanizing mold 2 flows to the mounting hole 28 through the vent hole 23, and reaches the segment 14 through the notch groove 29 c of the insert 29 through the center hole 30 a of the bolt 30. After that, it is discharged to the outside of the tire vulcanizing mold 2 through a gas vent groove (not shown). Further, when the mold clamping is completed, the vent hole 23 is closed by the stem 26, so that the rubber does not flow out of the vent hole 23.

  In the tire vulcanizing mold 2 having the above-described configuration, the sector 20 is replaced by changing the type of a tire to be vulcanized. In this case, the sector 20 has an insert 29 screwed into a mounting hole 28 formed in the outer surface 20b, and the bolt 30 does not directly contact the sector 20 made of an aluminum alloy. The bolt 30 screwed to the insert 29 has only a center hole 30a, and the male screw portion is not processed at all. Therefore, the work of screwing the bolt 30 to the insert 29 attached to the sector 20 can be performed smoothly without damaging the bolt 30.

  Note that the present invention is not limited to the configuration described in the above embodiment, and various modifications are possible.

  For example, in the above-described embodiment, the notch groove 29c is formed in the insert 29, but if the insert 29 is to be mounted so that a gap is formed between the insert 29 and the bottom surface of the mounting hole 28, Such a notch 29c is not always necessary. In place of the insert 29, various intermediate members such as a cylindrical member having an outer peripheral surface and a female screw formed on an inner peripheral surface can be employed.

  Further, in the above-described embodiment, the vent hole 23 is provided with the vent plug 24. However, the present invention is not limited to this, and the vent hole 23 may be constituted by a normal vent formed by a simple through-hole. It may be constituted by a piece vent into which a piece is press-fitted.

DESCRIPTION OF SYMBOLS 1 ... Vulcanization molding machine 2 ... Die for tire vulcanization 3 ... Upper plate 4 ... Upper platen 4a ... Flow path 5 ... Lower platen 5a ... Flow path 6 ... Container 7 ... Elevating cylinder 8 ... Elevating rod 9 ... Bladder unit 10 ... Spindle 11 ... Upper clamp 12 ... Lower clamp 13 ... Bladder 14 ... Segment 14a ... Outer side conical surface 15 ... Jacket ring 15a ... Inner side conical surface 16 ... Upper container plate 17 ... Lower container plate 18 ... Upper slide 19 ... Lower slide 20 ... Sector 20a ... Inner surface 20b ... Outer surface 20c ... Abutment surface 20d ... Relief surface 21 ... Upper die 22 ... Lower die 23 ... Vent hole 24 ... Vent plug 25 ... Housing 26 ... Stem 27 ... Spring 28 ... Mounting hole 29 … Ensert (an example of intermediate member)
29a ... male screw 29b ... female screw 29c ... notch groove 30 ... bolt 30a ... center hole 31 ... upper bead ring 32 ... lower bead ring

Claims (6)

A tire vulcanizing mold having a plurality of annular sectors arranged side by side in the circumferential direction,
Each of the sectors communicates an inner surface constituting a tread molding surface, an outer surface located on a radially opposite side to the inner surface , a mounting hole formed in the outer surface, and the inner surface and the mounting hole. has a vent hole, the,
A segment that supports the sector from the outer surface side and has a fastening hole formed concentrically with the axis of the mounting hole;
Wherein are screwed into the mounting hole, and the intermediate member that having a female screw portion on the inner diameter portion,
Through the clamping hole from the segment side, and the screwed into the female threaded portion of the intermediate member, the bolt having a through hole extending in axial direction are formed,
A tire vulcanizing mold comprising:   The mold for vulcanizing a tire according to claim 1, wherein the intermediate member is attached with a gap between the intermediate member and a bottom surface of the attachment hole.   3. The bolt according to claim 1, wherein in a state where the intermediate member is screwed into the mounting hole, a position of a leading end of the bolt to the intermediate member is separated from a bottom surface of the mounting hole. 4. Mold for tire vulcanization. 4. The tire vulcanizing metal according to claim 3 , wherein the intermediate member has a cutout groove extending from one end surface contacting the bottom surface of the mounting hole toward the other end surface, and communicating the inner surface with the outer surface. 5. Type.   The mold for vulcanizing a tire according to any one of claims 1 to 4, wherein the sector has a spring vent disposed on an inner surface where the vent hole is opened. A tire manufacturing method for vulcanizing and molding a green tire using the tire vulcanizing mold according to any one of claims 1 to 5 ,
During clamping, the internal gas through the vent hole from the inner surface side of said sector to flow into the mounting hole, in the axial direction of the bolt screwed to the intermediate member to be screwed into the mounting hole tire manufacturing method characterized by discharging to the outside of the sector through the extending through hole.

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