JP2016210091A - Die for tire vulcanization - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a die for tire vulcanization capable of easily suppressing reduction of productivity by making cutting squeezed rubber formed on a tire surface easy in a vulcanization molding by using a split mold and suppressing breakage of a die due to jamming of a low cover by reducing generation tire scrap.SOLUTION: There is provided a die for tire vulcanization having a plurality of segments, having a cavity surface for tread molding separated in a circumferential direction and a pair of side plates, having a cavity surface for side wall molding and having notch part arranged in a cavity surface side peripheral part of the segment so that a wedge-shaped space expanding to inner direction from the cavity surface formed on a contact surface between the segment and the side plate at a close status.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a tire vulcanization mold used for vulcanization molding in the manufacture of a pneumatic tire.

  A pneumatic tire is manufactured by vulcanizing a raw cover using a tire vulcanization mold (for example, Patent Documents 1 and 2).

  As the tire vulcanization mold, a pair of upper and lower side molds having a cavity surface for molding a tire third wall portion, and a plurality of (usually 3 to 20) cavity surfaces for molding a tire tread portion. ), So-called split molds may be used.

  By closing such a split mold, a plurality of segments are connected in a ring shape to form a tread surface of the tire, and the raw cover is heated and pressed together with the ring-shaped side mold to vulcanize the raw cover. Molding is performed.

Japanese Patent Application Laid-Open No. 8-103973 Japanese Patent Laid-Open No. 11-77694

  However, when the tire vulcanization mold is closed, it is difficult to completely adhere the side plate and the segment, and a thin film-like rubber (extruded rubber) is generated along a slight gap.

  The produced rubber is cut off after vulcanization, but if the thickness is less than 0.1 mm, it takes time to cut off, and the productivity of the tire may be significantly reduced. Further, if the protruding rubber remains in the mold after vulcanization, it may be mixed at the time of the next tire vulcanization and cause tire scrap. Furthermore, if the raw cover bites between the side plate and the segment, the mold may be damaged.

  Accordingly, the present invention provides a vulcanization molding using a split mold that facilitates excision of the protruding rubber formed on the tire surface to suppress a decrease in productivity, reduce generation of tire scrap, It is an object of the present invention to provide a tire vulcanization mold that can suppress damage to the mold due to biting of the tire.

  As a result of intensive studies to solve the above problems, the present inventor has found that the above problems can be solved by the invention described below, and has completed the present invention.

The invention described in claim 1
A tire vulcanization mold comprising a plurality of segments having a cavity surface for tread molding divided in the circumferential direction and a pair of upper and lower side plates having a cavity surface for sidewall molding,
When the closed state is established, a wedge-shaped space extending inward from the cavity surface is formed on the contact surface between the segment and the side plate. A tire vulcanization mold characterized in that a notch is provided.

The invention described in claim 2
The cross-sectional shape of the notch is
A cavity surface side rectangular portion which is a rectangle provided on the cavity surface side;
An inner rectangular portion which is provided on the inner side and is a rectangle wider than the cavity surface side rectangular portion;
The cavity surface side rectangular portion and the inner rectangular portion are connected to each other, and an intermediate trapezoidal portion which is a trapezoid whose width is widened by an inclined side from the cavity side rectangular portion to the inner rectangular portion. The tire vulcanization mold according to claim 1, wherein:

The invention according to claim 3
In the cross-sectional shape of the notch, the width of the inner rectangular portion is 1.5 mm or more,
The inward length of the cavity side rectangular part is 1.5 mm or less,
The inward length of the notch is 3.0 mm or more,
The cavity side rectangular portion has a width of 0.15 to 0.3 mm,
The tire vulcanization mold according to claim 2, wherein an inclination angle of the inclined side of the intermediate trapezoidal portion is 30 to 45 °.

  According to the present invention, in the vulcanization molding using a split mold, it is possible to easily cut out the protruding rubber formed on the tire surface to suppress the decrease in productivity, reduce the generation of tire scrap, Thus, it is possible to provide a tire vulcanization mold capable of suppressing damage to the mold due to the biting.

It is a typical side view which shows the position of the notch part in the metal mold | die for tire vulcanization | cure which concerns on one embodiment of this invention. It is sectional drawing of the notch which expanded the part enclosed with the circle in FIG.

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

1. Outline of Tire Vulcanization Mold According to this Embodiment First, an outline of a tire vulcanization mold according to this embodiment will be described.

  The tire vulcanization mold according to the present embodiment includes a plurality of segments and a pair of upper and lower side plates as in the conventional tire vulcanization mold. And the some segment is divided | segmented and arrange | positioned in the circumferential direction, and has the cavity surface for tread shaping | molding. Further, the pair of upper and lower side plates has a cavity surface for side wall molding.

  However, unlike the conventional tire vulcanization mold, when the tire vulcanization mold according to the present embodiment is in a closed state, the contact surface between the segment and the side plate faces inward from the cavity surface. In order to form a wedge-shaped space that expands, a notch is provided in the cavity surface side edge of the segment.

  By providing such a notch to form a wedge-shaped space, in the tire vulcanization mold that was closed during vulcanization, rubber entered the wedge-shaped space and became a lump. Since the protruding rubber is generated, it is possible to suppress the generation of a thin film-shaped protruding rubber on the contact surface between the segment and the side plate.

  Unlike the thin film-like protruding rubber, the protruding rubber that has become a lump can be easily excised in a normal spew trimming process, so that a reduction in productivity can be suppressed.

  And by providing a notch part, it can also suppress that the rubber | gum which protrudes into a tire vulcanization metal mold | die remains, Therefore Generation | occurrence | production of a tire scrap can be reduced. In addition, damage to the mold due to biting of the raw cover can be suppressed.

2. Tire vulcanization mold and wedge-shaped space Next, the tire vulcanization mold and the wedge-shaped space according to the present embodiment will be described in detail.

  As described above, the tire vulcanization mold includes a plurality of segments arranged in an annular shape and a pair of upper and lower side plates. Each of these tire vulcanization molds is in a closed state. The raw cover is vulcanized by contacting the contact surface and heating and pressing.

  FIG. 1 is a schematic side view showing the position of a notch in the tire vulcanization mold according to the present embodiment. In FIG. 1, 1 is a segment, 2 is a side plate, 3 is a contact surface between the segment and the side plate, 4 is a cavity surface in contact with the tire, and 5 is a wedge-shaped space.

  The wedge-shaped space 5 is formed by a notch provided at the cavity surface side edge of the segment 1 and is connected around in the circumferential direction to make one round.

  In the cross section of the wedge-shaped space 5, the wedge-shaped space 5 extends from the surface (cavity surface) in contact with the tire of the segment 1 to the inside, and extends from a certain position while expanding the width to exhibit a wedge shape. Yes.

  With this tire vulcanization mold, when the vulcanized tire is removed from the mold, the protruding rubber is wedge-shaped and the tip becomes a large lump, so it will not be overlooked during the spew trimming process, and Because the base side is thin, it can be easily removed. For this reason, it can be cut surely and easily in the spew trimming process, and no spew remains on the tire. As a result, a pneumatic tire with excellent appearance quality can be provided without reducing the productivity of the tire.

  Further, since the protruding rubber remaining in the mold is reduced, generation of tire scrap due to mixing of the protruding rubber can be suppressed. Further, since the load on the mold due to the low cover biting between the side plate and the segment is reduced, the damage to the mold is suppressed, and the necessity of mold repair is reduced.

  As described above, by using the tire vulcanization mold according to the present embodiment, in the vulcanization molding using the split mold, it is easy to cut out the protruding rubber formed on the tire surface, thereby reducing the productivity. While suppressing, generation | occurrence | production of a tire scrap can be reduced and damage to the metal mold | die by biting of a raw cover can be suppressed.

3. About Wedge-shaped Space FIG. 2 is a cross-sectional view of a notch in which a portion surrounded by a circle in FIG. 1 is enlarged.

  As described above, a wedge-shaped space can be formed by providing such a notch. As shown in FIG. 2, the cutout portion has a cavity surface side rectangular portion having a rectangular shape provided on the cavity surface side and a rectangular shape provided on the inner side and wider than the cavity surface side rectangular portion. An intermediate trapezoidal portion which is a trapezoid whose width is widened by an inclined side from the cavity side rectangular portion to the inner rectangular portion, connecting the inner rectangular portion, the cavity surface side rectangular portion and the inner rectangular portion, It is composed of

  In the cross-sectional shape of the notch, the width a of the inner rectangular portion is 1.5 mm or more, the length b toward the inside of the cavity-side rectangular portion is 1.5 mm or less, and the notch The inward length c is 3.0 mm or more, the width d of the cavity side rectangular part is 0.15 to 0.3 mm, and the inclined angle e of the inclined side of the intermediate trapezoidal part It is preferable that the inclination angle e) of the side opposite to the side in contact with the contact surface with respect to the contact surface is 30 to 45 °.

  In this way, by inclining by the length of b and then by inclining the angle of e, the shape of the protruding rubber changes greatly before and after this inclination, so the spew cutting process can be easily performed at the portion of b. It can be performed. As a result, the size of the spew left on the tire can be kept within a maximum height (b) of 1.5 mm × thickness (d) of 0.3 mm. The thickness direction of 2.0 mm or less and the thickness direction of 0.3 mm or less can be easily cleared.

1. Production of pneumatic tire (Example 1)
In the two-stage tire vulcanizer, the raw cover is vulcanized using a split mold provided with a notch of the size shown in FIG. Sputum trimming was performed to manufacture a pneumatic tire having a tire size of 175 / 65R15.

(Comparative Example 1)
A pneumatic tire was manufactured in the same manner as in Example 1 except that a split mold without a conventional notch was used.

(Comparative Example 2)
A pneumatic tire was manufactured in the same manner as in Example 1 except that a split mold having a rectangular notch having a size shown in Table 1 was used.

2. Evaluation Each of the obtained pneumatic tires was visually evaluated to determine whether there was any uncut rubber left in the circumferential direction after spew trimming, and whether the protruding rubber remained between the segment and the side plate. In addition, the judgment is expressed in three stages: “good”, “possible”, and “impossible”. The results are shown in Table 1.

  As shown in Table 1, in the case of the conventional split mold not provided with the notch (Comparative Example 1), the spume trimming cannot be automatically cut, and the thin film-like rubber remains and the visual inspection of the appearance becomes “possible”. 2% tire scrap was generated and 5% NG tires were generated.

  In the case of a split mold provided with an elongated rectangular cutout (Comparative Example 2), although it is possible to perform automatic spew trimming, the appearance visual inspection is still “possible” due to the presence of the appearance NG. Although no scrap was generated, 3% of NG tires were generated.

  On the other hand, in the case of a split mold provided with a wedge-shaped notch (Example 1), all of them are within the standard by automatic sput trimming, and the visual inspection is “good”. Scrap generation and NG tire generation were 0%.

  While the present invention has been described based on the embodiments, the present invention is not limited to the above embodiments. Various modifications can be made to the above-described embodiment within the same and equivalent scope as the present invention.

1 Segment 2 Side plate 3 Abutment surface between segment and side plate 4 Cavity surface in contact with tire 5 Wedge-shaped space a, d Width b, c Length e Inclination angle

Claims (3)

A tire vulcanization mold comprising a plurality of segments having a cavity surface for tread molding divided in the circumferential direction and a pair of upper and lower side plates having a cavity surface for sidewall molding,
When the closed state is established, a wedge-shaped space extending inward from the cavity surface is formed on the contact surface between the segment and the side plate. A mold for vulcanizing a tire, wherein a notch is provided. The cross-sectional shape of the notch is
A cavity surface side rectangular portion which is a rectangle provided on the cavity surface side;
An inner rectangular portion which is provided on the inner side and is a rectangle wider than the cavity surface side rectangular portion;
The cavity surface side rectangular portion and the inner rectangular portion are connected to each other, and an intermediate trapezoidal portion which is a trapezoid whose width is widened by an inclined side from the cavity side rectangular portion to the inner rectangular portion. The tire vulcanization mold according to claim 1. In the cross-sectional shape of the notch, the width of the inner rectangular portion is 1.5 mm or more,
The inward length of the cavity side rectangular part is 1.5 mm or less,
The inward length of the notch is 3.0 mm or more,
The cavity side rectangular portion has a width of 0.15 to 0.3 mm,
The tire vulcanization mold according to claim 2, wherein an inclination angle of the inclined side of the intermediate trapezoidal portion is 30 to 45 °.

Images