JP7202896B2 - tire vulcanization mold - Google Patents

Description

The present invention relates to tire vulcanization molds.

A tire vulcanization mold disclosed in Patent Document 1 includes an annular sector mold having a plurality of sectors divided in the circumferential direction for molding a tread portion of a pneumatic tire. These sectors are provided with molding surfaces having ribs for molding grooves in the tread, and ribs protruding from the ribs for molding sipes in the groove bottoms.

JP-A-10-58458

Since the tire vulcanizing mold is periodically cleaned by shot blasting, the molding surface is worn by the cleaning material (for example, sand) being sprayed. As the wear of the molding surface progresses, grooves of a predetermined depth cannot be formed in the tread portion, so it is necessary to repair the molding surface by build-up or the like. However, in the tire vulcanization mold of Patent Document 1, no consideration is given to the determination of the wear amount of the sectors.

SUMMARY OF THE INVENTION An object of the present invention is to provide a tire vulcanization mold that can easily determine the wear amount of a sector.

One aspect of the present invention includes an annular sector mold configured by a plurality of sectors divided in the circumferential direction, each of the plurality of sectors having ribs for forming grooves in the tread portion of the pneumatic tire. and at least one of the plurality of sectors is formed on the molding surface and protruded from the molding surface for determining the amount of wear of the molding surface. and having at least one step made of a material having a hardness different from that of the sector .

In this tire vulcanization mold, when the sector is cleaned by shot blasting, the molding surface including the step portion that functions as an indicator is worn. At this time, by confirming the wear amount of the stepped portion, it is possible to easily determine when to repair the sector. Then, when it is determined that it is time for repair, the groove pattern determined in the tread portion can be reliably formed by repairing (building up) the forming surface of the sector.

A projection dimension of the projection from the molding surface to the tip end face of the projection is 0.1 mm or more and equal to or less than a predetermined height tolerance of the bone portion. According to this aspect, it is possible to easily determine when to repair the sector based on the wear of the convex portion.

The stepped portion is formed on the top surface of the bone portion. Alternatively, the stepped portion is formed on the side surface of the bone portion. The convex portion is formed on the side surface of the bone portion. Here, during cleaning, the cleaning material is strongly sprayed onto the portion protruding from the molding surface, so that the protruding portion wears faster than the other portions. Further, according to this aspect, since the stepped portion is provided on the bone protruding from the molding surface, the stepped portion wears the fastest. That is, before the molding surface of the sector reaches the wear limit, it is possible to reliably determine when to repair the sector based on the wear of the stepped portion.

In the tire vulcanizing mold of the present invention, it is possible to easily determine when to repair a sector by checking the amount of wear of the step portion that functions as an indicator.

BRIEF DESCRIPTION OF THE DRAWINGS Sectional drawing which shows the tire vulcanization molding machine using the tire vulcanization mold which concerns on 1st Embodiment of this invention. FIG. 2 is a cross-sectional view showing the tire vulcanizing machine in a mold open state; The front view which looked at the sector from the radial inside. FIG. 2B is a cross-sectional view of a main part of FIG. 2A; FIG. 4 is an enlarged cross-sectional view showing a stepped portion formed on a bone portion of a sector; Partial sectional view of a pneumatic tire. FIG. 11 is an enlarged cross-sectional view showing a stepped portion formed in the bone portion of the sector of the second embodiment; FIG. 5 is a cross-sectional view showing a modification of a stepped portion formation site with respect to a bone portion;

Embodiments of the present invention will be described below with reference to the drawings.

(First embodiment)
1A and 1B show a tire vulcanizing machine (hereinafter referred to as "vulcanizing machine") using a tire vulcanizing mold (hereinafter referred to as "mold") 50 according to the first embodiment of the present invention. 10 is shown. The mold 50 includes a sector mold 51, an upper mold (side mold) 52, and a lower mold (side mold) 54 for molding the pneumatic tire 1 shown in FIG. is attached to the container 30 of the

(Overview of vulcanization molding machine)
As shown in FIG. 1A, vulcanization molding machine 10 comprises frame 20, container 30, bladder unit 40, and mold 50 of the present invention. The bladder unit 40 and the mold 50 define a cavity for vulcanizing the green tire 1'. By driving the frame 20 by a drive mechanism (not shown), the mold 50 is switched between the clamped state shown in FIG. 1A and the mold opened state shown in FIG. 1B.

As shown in FIGS. 1A and 1B, frame 20 includes plate 21 , upper platen 22 and lower platen 23 .

Plate 21 is fixed to the lower end of lifting member 24 . The upper platen 22 is fixed to the lower end of an elevating member 25 arranged in the center of the elevating member 24 . The lower platen 23 is fixed at a predetermined position below the upper platen 22 . The elevating members 24 and 25 each have a drive mechanism, and elevate the plate 21 and the upper platen 22 independently. The upper platen 22 has a channel 22a and the lower platen 23 has a channel 23a. The mold 50 can be adjusted to a desired vulcanization temperature via the upper platen 22 and the lower platen 23 by adjusting the temperature of the heat exchange medium (for example, oil) flowing through these flow paths 22a and 23a.

With continued reference to FIGS. 1A and 1B, container 30 comprises a plurality of segments 31 , jacket 32 , upper plate 33 and lower plate 35 .

The segments 31 are provided in the same number as the plurality of sectors 51A constituting the sector mold 51, and each sector 51A is screwed. The outer surface of the segment 31 in the radial direction X of the sector mold 51 is composed of an inclined surface 31a that gradually widens (inclines) downward from above. The plurality of segments 31 are respectively attached to a plurality of upper slides 34 fixed to the upper plate 33 and are reciprocally movable in the radial direction X of the sector mold 51 with respect to the upper slides 34 .

The jacket 32 has a cylindrical shape capable of covering the outer periphery of the mold 50 in the open state shown in FIG. 1B and is fixed to the lower surface of the plate 21 . The jacket 32 moves up and down via the plate 21 according to the up-and-down motion of the elevating member 24 . When the plate 21 descends, the jacket 32 presses the inclined surface 31a with the inclined surface 32a located inside in the radial direction X, moving the segments 31 inward in the radial direction X, and connecting the plurality of segments 31 in a ring shape. be arranged (side by side).

The upper plate 33 is fixed to the lower surface of the upper platen 22 and moves up and down via the upper platen 22 according to the up-and-down motion of the elevating member 25 . An upper slide 34 is fixed to the outer periphery of the upper plate 33, and an upper mold 52 is fixed to the inner side thereof. The lower plate 35 is fixed to the upper surface of the lower platen 23 . A lower slide 36 is fixed to the outer periphery of the lower plate 35, and a lower mold 54 is fixed to the inner side thereof.

1A and 1B, the bladder unit 40 includes a spindle 41, an upper clamp 42, a lower clamp 43, and a bladder 44. As shown in FIG.

The support shaft 41 is arranged at the center of the lower platen 23 and has a rod 41a that can be raised and lowered in the width direction (axial direction) Y of the sector mold 51 by a drive mechanism (not shown). The upper clamp 42 is fixed to the rod 41a, and the lower clamp 43 is fixed to the main body of the support shaft 41. As shown in FIG. The interval in the width direction Y between the upper clamp 42 and the lower clamp 43 is adjusted by raising and lowering the rod 41a by driving the drive mechanism. The bladder 44 has an upper inner peripheral edge attached to the upper clamp 42 and a lower inner peripheral edge attached to the lower clamp 43 . Air is supplied to and discharged from the space surrounded by the upper clamp 42, the lower clamp 43, and the bladder 44 by an air supply/exhaust device (not shown). The bladder 44 is inflated by being supplied with air, and supports the green tire 1' from the inner side in the tire radial direction.

(Outline of tire vulcanization mold)
1A and 1B, mold 50 comprises sector mold 51, upper mold 52, and lower mold 54, as previously described.

The sector mold 51 includes sectors 51A each having a sector shape in a plan view and formed by dividing an annular body into a plurality (for example, seven) in the circumferential direction Z. As shown in FIG. Individual sectors 51A are attached to segments 31 respectively. In the clamped state shown in FIG. 1A, a plurality of sectors 51A are arranged in an annular shape with an inner diameter corresponding to the outer diameter of the tire to be molded. In the radial direction X of the sector mold 51, the inner surface of the sector 51A forms a molding surface 51a for molding the tread portion 2 (see FIG. 3) of the pneumatic tire 1, and the outer surface of the sector 51A forms a molding surface 51a for attaching to the segment 31. It constitutes the mounting surface 51b.

The upper mold 52 has an annular shape and is fixed to the lower surface of the upper plate 33 so as to be positioned above the green tire 1'. The upper mold 52 moves up and down via the upper plate 33 according to the up-and-down motion of the elevating member 25 . An upper bead ring 53 is fixed to the inner peripheral portion of the upper mold 52 . The inner surface of the upper mold 52 located on the lower side in FIGS. 1A and 1B constitutes a molding surface 52a for molding one of a pair of side portions (not shown) of the tire 1, and an upper bead ring 53. constitutes a molding surface 53a for molding one of a pair of bead portions (not shown) of the tire 1 . The outer surface of the upper mold 52 located on the upper side in FIGS. 1A and 1B forms a mounting surface 52b for mounting to the upper plate 33, and the outer surface of the upper bead ring 53 forms a mounting surface 53b for mounting to the upper mold 52. Constitute.

The lower mold 54 has an annular shape like the upper mold 52, and is fixed to the upper surface of the lower plate 35 so as to be positioned below the green tire 1'. A lower bead ring 55 is fixed to the inner peripheral portion of the lower mold 54 . The inner surface of the lower mold 54 located on the upper side in FIGS. 1A and 1B constitutes a molding surface 54a for molding the other of the pair of side portions of the tire 1, and the inner surface of the lower bead ring 55 is the tire. A molding surface 55a for molding the other of the pair of beads is formed. The outer surface of the lower mold 54 located on the lower side in FIGS. 1A and 1B forms a mounting surface 54b for mounting to the lower plate 35, and the outer surface of the lower bead ring 55 forms a mounting surface 55b for mounting to the lower mold 54. configure.

In the mold 50 configured in this way, the green tire 1 ′ is placed on the lower mold 54 in the opened state shown in FIG. In this state, air is supplied to inflate the bladder 44, and in a state in which the inner surface of the green tire 1' is held by the outer surface thereof, the lifting members 24 and 25 are lowered by driving the drive mechanism, thereby allowing the air to flow in FIG. 1A. The mold 50 is clamped as shown in .

The rubber of the green tire 1' adheres to the molding surfaces 51a to 55a by pressing from the mold 50. As shown in FIG. A heat exchange medium adjusted to a predetermined temperature is constantly flowing between the upper platen 22 and the lower platen 23 . As a result, the rubber of the green tire 1' is vulcanized, and the pneumatic tire 1 having the prescribed outer surface shape shown in FIG. 3 is completed.

As shown in FIGS. 2A and 2B, bone portions 56 and 57 projecting inward in the radial direction X of the sector mold 51 are formed on the molding surface 51a of the sector 51A. Referring also to FIG. 3 , the main groove 4 extending in the tire circumferential direction is formed on the outer surface of the tread portion 2 of the tire 1 by the bone portion 56 . The lateral grooves 5 extending in the tire width direction Y are formed in the shoulder portions 3 positioned on both sides of the tread portion 2 in the tire width direction by the bone portions 57 .

The sector 51A, the upper mold 52, the upper bead ring 53, the lower mold 54, and the lower bead ring 55, which constitute the sector mold 51, are cleaned periodically (for example, a predetermined number of times of vulcanization). The washer is shown in FIG. 2B. As shown in FIG. 2B, the washer comprises a nozzle 65 for spraying a cleaning material 66 such as sand. When cleaning the sector 51A, the nozzle 65 is swung in the width direction Y and the circumferential direction Z of the sector mold 51, and the cleaning material 66 is sprayed all over the molding surface 51a (shot blasting).

If the molding surfaces 51a to 55a are excessively worn by washing, the tire 1 having a predetermined shape cannot be molded. In particular, bones 56 and 57 of sector 51A protrude more than other parts, and the cleaning material 66 is strongly sprayed thereon during cleaning, so that wear progresses more easily than other parts. If the bone portions 56 and 57 are excessively worn, the grooves 4 and 5 having a predetermined depth cannot be formed. In order to prevent such inconvenience, the present embodiment is as follows.

(sector details)
As shown in FIGS. 2A and 2B, the molding surface 51a of the sector 51A is provided with a convex portion 60 for determining when to repair the molding surface 51a. As a result, a stepped portion is formed between the molding surface 51a and the convex portion 61 for determining the amount of wear of the molding surface 51a. The convex portion 60 may be formed in all sectors 51A, or may be formed in one of the plurality of sectors 51A. When the convex portion 60 is provided in only one sector 51A, the repair timing determination based on the wear amount of the convex portion (stepped portion) 60 is applied to all the sectors 51A.

Specifically, the sector 51A includes four bone portions 56 extending in the circumferential direction Z of the sector mold 51 and a plurality of bone portions 57 extending in the width direction Y. As shown in FIG. The four bone portions 56 are provided at intervals in the width direction Y. As shown in FIG. A plurality of bone portions 57 are provided at intervals in the circumferential direction Z. As shown in FIG. Between the side surfaces 56a of the bone portion 56 adjacent in the width direction Y is a concave portion 58 for forming the rib 6 (see FIG. 3) of the tire 1. As shown in FIG. The interior surrounded by the side surfaces 57b of the bone portions 57 adjacent in the circumferential direction Z and the side surfaces 56a of the bone portions 56 is a recess 59 for molding the block 7 of the tire 1 (see FIG. 3). All the inner surfaces of the ribs 56, 57 and the recesses 58, 59 form the shaping surface 51a of the sector 51A.

The convex portion 60 functioning as an indicator is made of a material (for example, stainless steel) having higher hardness than the aluminum sectors 51A. For example, the convex portion 60 is formed by welding a plate material having a hardness higher than that of the sectors 51A, or by welding a material that becomes higher in hardness than the sectors 51A by hardening. Further, the surface of the convex portion 60 made of aluminum may be coated with a coating having a hardness higher than that of the sectors 51A. In this way, by using different materials for the sector 51A and the convex portion 60, it is possible to provide a difference in the degree of progress of wear. .

The convex portions 60 are formed on the top surfaces 56a and 57a of all bone portions 56 and 57, which are more likely to be worn by washing than other portions. As shown most clearly in FIG. 2A, the convex portion 60 is formed in a circular shape (cylindrical shape) when the sector 51A is viewed from the inside of the sector mold 51 in the radial direction X. As shown in FIG. However, the convex portion 60 may be square or triangular, and the shape may be changed as necessary. Also, the convex portion 60 may be a pattern of protruding filaments.

As shown in FIG. 2C, the convex portion 60 protrudes from the top surfaces 56a and 57a of the bone portions 56 and 57 with a uniform thickness (protrusion dimension T1). That is, when the top surfaces 56a and 57a are flat surfaces, the tip surface 60a of the convex portion 60 is formed as a flat surface parallel to the top surfaces 56a and 57a, and when the top surfaces 56a and 57a are curved surfaces, the tip surface 60a is flat. It is formed in a curved surface concentric with the surfaces 56a and 57a.

The projection dimension T1 of the projection 60 from the top surfaces 56a and 57a (molding surface 51a) to the tip surface 60a is the projection dimension of the bone portions 56 and 57 from the bottom surfaces 58a and 59a of the recesses 58 and 59 to the top surfaces 56a and 57a. It is set to be smaller than T2 and equal to or less than the defined height tolerance of bone portions 56 and 57 . More specifically, the protrusion dimension T2 of the bone portions 56 and 57 is 1 mm to 15 mm, and the dimension value of the height tolerance is 0.3 mm. This value of the height tolerance of the ribs 56, 57 corresponds to the wear limit of the ribs 56 necessary to form the grooves 4, 5 of defined depth. On the other hand, the projection dimension T1 of the convex portion 60 is set to 0.1 mm or more and 0.3 mm or less.

If the projection dimension T1 of the projection 60 is excessively small, there is a high possibility that the molding surface 51a will not reach the wear limit even if the projection 60 is worn, and the number of repairs of the sector 51A will increase unnecessarily. If the projection dimension T2 of the convex portion 60 is made larger than the height tolerance of the bone portions 56 and 57, the molding surface 51a may reach the wear limit even if the convex portion 60 is not worn out. There is a possibility that the grooves 4 and 5 having the specified depth cannot be formed in the tire 1 . In order to prevent these inconveniences, it is preferable to set the projection dimension T1 of the projection 60 within the range defined above. In this way, if the protrusion 60 is not worn out, it can be determined that the repair time has not come, and if the protrusion 60 is worn out, it can be determined that the repair time has arrived.

As described above, since the convex portion 60 functioning as an indicator is provided on the molding surface 51a, the amount of wear of the convex portion 60 (difference from the molding surface 51a) due to washing of the sector 51A can be confirmed. It is possible to easily judge the repair time of 51A. Then, when it is determined that it is time for repair, the predetermined groove pattern of the tread portion 2 can be reliably formed by repairing (building up) the forming surface 51a including the convex portion 60. FIG. The tire 1 formed by the sector 51A having the projections 60 has recesses 8 having shapes corresponding to the projections 60 at the bottoms of the grooves 4 and 5, as shown in FIG.

Since the projecting dimension T1 of the convex portion 60 is set to be equal to or less than the height tolerance (abrasion limit value) of the bone portions 56 and 57, it is possible to easily repair the sector 51A by checking whether the convex portion 60 is worn out. can be judged. Since the convex portions 60 are formed on the top surfaces 56a and 57a of the bone portions 56 and 57, which wear progresses fastest due to washing, it is possible to repair the sector 51A before the molding surface 51a of the sector 51A reaches the wear limit. can be determined with certainty.

(Second embodiment)
FIG. 4 shows bone portions 56 and 57 (molding surface 51a) of a sector 51A of the second embodiment in which stepped portions are formed as indicators. In the second embodiment, a stepped portion is formed between the molding surface 51a and the molding surface 51a by a concave portion 62 instead of the convex portion 60 of the first embodiment.

The concave portion 62 is recessed from the molding surface 51a toward the bases of the bone portions 56 and 57. As shown in FIG. The shape of the concave portion 62 when viewed from the radial direction of the sector mold is circular, as in the first embodiment. may be

The recessed portion 62 is recessed from the top surfaces 56a, 57a of the bone portions 56, 57 to a uniform depth (dimension T1). The dimension T1 of the recess 62 from the bottom surface 62a to the top surfaces 56a and 57a (molding surface 51a) is smaller than the projecting dimension T2 of the bone portions 56 and 57, as in the first embodiment. height tolerance (0.1 mm or more and 0.3 mm or less).

In the sector 51A of the second embodiment, the molding surface 51a becomes flush with the bottom surface 62a of the recess 62 due to wear, so that the repair timing can be easily determined. Therefore, it is possible to obtain the same actions and effects as in the first embodiment. In the tire 1 formed using the sector 51A, convex portions corresponding to the concave portions 62 are formed on the ribs 6 and the blocks 7. As shown in FIG. This convex portion is the first to be worn out by running.

(Modification)
FIG. 5 shows a modified example of the forming part of the step with respect to the bones 56 and 57 of the sector 51A. In this modification, side surfaces 56b and 57b of bone portions 56 and 57 are provided with protrusions 60 similar to those in the first embodiment. However, recesses 62 may be provided instead of the protrusions 60 as in the second embodiment.

The projection dimension of the projection 60 from the side surfaces 56b, 57b to the tip surface 60a is the same as in the first embodiment shown in FIG. 2C. The shape of the convex portion 60 is also the same as that of the first embodiment, and is provided only on part of the side surfaces 56b and 57b of the bone portions 56 and 57. As shown in FIG. In the tire 1 formed by this sector 51A, concave portions corresponding to the convex portions 60 are formed only on part of the side surfaces of the ribs 6, unlike the silent wall. A silent wall is a configuration in which a plurality of grooves and ridges are provided on the side surface of the rib 6 alternately and continuously in the tire circumferential direction and extending in the tire radial direction.

With this mold 50, the timing for repairing the sector 51A can be easily determined based on the amount of wear of the convex portion (stepped portion) 60, as in the first embodiment. In addition, since the grooves 4 and 5 are provided with recesses on the side surfaces of the tire 1 , the appearance of the tire 1 is not affected by the formation of the protrusions 60 .

The tire vulcanization mold 50 of the present invention is not limited to the configuration of the above-described embodiment, and various modifications are possible.

For example, the stepped portion formed by the convex portion 60 or the concave portion 62 may be provided on only one of all bone portions 56 and 57, or may be provided on two or more bone portions. If only one protrusion 60 or recess 62 is provided, it is preferably formed on one of the four bones 56 . The number of convex portions 60 or concave portions 62 formed in one bone portion 56, 57 may be one, or two or more. The formation position of the convex portion 60 or the concave portion 62 with respect to the bone portions 56 and 57 can be changed as required.

Further, the stepped portion formed by the convex portion 60 or the concave portion 62 may be provided at the bottom of the concave portions 58 and 59 forming the molding surface 51a. The dimension T1 of the projection 60 or the recess 62 may be larger than the height tolerance of the bones 56 and 57 by providing a mark (scale) at a position corresponding to the wear limit on the projection 60 or the recess 62.

1' green tire 1 pneumatic tire 2 tread portion 3 shoulder portion 4 main groove 5 lateral groove 6 rib 7 block 8 concave portion 10 tire vulcanizing machine 20 frame 21 plate 22 upper platen 22a channel 23 lower platen 23a channel 24 lifting member 25 lifting member 30 container 31 segment 31a inclined surface 32 jacket 32a inclined surface 33 upper plate 34 upper slide 35 lower plate 36 lower slide 40 bladder unit 41 spindle 41a rod 42 upper clamp 43 lower clamp 44 bladder 50 tire vulcanization mold 51 sector mold 51A sector 51a molding surface 51b mounting surface 52 upper mold 52a molding surface 52b mounting surface 53 upper bead ring 53a molding surface 53b mounting surface 54 lower mold 54a molding surface 54b mounting surface 55 lower bead ring 55a molding surface 55b mounting surface 56 bone Portion 56a Top surface 56b Side surface 57 Bone portion 57a Top surface 57b Side surface 58 Recessed portion 58a Bottom surface 59 Recessed portion 59a Bottom surface 60 Protruding portion (stepped portion)
60a tip surface 62 concave portion (stepped portion)
62a Bottom surface 65 Nozzle 66 Cleaning material X Radial direction of sector mold Y Width direction of sector mold Z Circumferential direction of sector mold

Claims (4)

Equipped with an annular sector mold composed of a plurality of sectors divided in the circumferential direction,
each of the plurality of sectors has a molding surface on which ribs for forming grooves in the tread portion of the pneumatic tire protrude;
At least one of the plurality of sectors is formed on the molding surface and configured by a convex portion protruding from the molding surface for determining the wear amount of the molding surface, and the sector has a hardness. A tire curing mold having at least one shoulder made of a different material . 2. The tire vulcanization mold according to claim 1, wherein the projection dimension of the projection from the molding surface to the tip end face of the projection is 0.1 mm or more and equal to or less than a predetermined height tolerance of the bone portion. . The tire vulcanizing mold according to claim 1 or 2 , wherein the step portion is formed on the top surface of the bone portion. The tire vulcanization mold according to claim 1 or 2 , wherein the step portion is formed on a side surface of the bone portion.

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