JPH03261515A - Vulcanizing mold - Google Patents

Abstract

PURPOSE:To improve resistance to wear of a marked section for forming letters, patterns, diagrams and the like on an outer profile section of a tire by constituting at least a part of a recessed section positioned between two projecting lines of a segment by a metal harder than the remaining molded section. CONSTITUTION:Most part of a vulcanizing mold is formed with a metal of comparatively low hardness and easy to be cast such as aluminum alloy or the like, and a marked section 50 is formed with a metal of hardness higher than those of other constituting sections such as steel. For instance, the shape such as a steel block is recessed into a part of a recessed section 40 of a segment 20 and fixed to a mold main body. Markings such as letters, patterns and diagrams can be applied easily to the marked section 50, and what is more, high resistance to wear is available because of its high hardness, and the marks are hard to get worn even if the vulcanizing mold is used or cleaned repeatedly, and cleaner letters, patterns, diagrams and the like can be marked clearly on the tire for a long period of time.

Description

[Detailed Description of the Invention] [Object of the Invention] (Industrial Field of Application) The present invention relates to an improvement in a vulcanization mold for a tire mold, and more specifically, to an improvement in vulcanization molds for tire molds, and more particularly, to improvements in vulcanization molds for tire molds, and more specifically, to The present invention relates to a vulcanization mold that improves the abrasion resistance of the stamping part for forming characters, patterns, figures, etc. on the outer contour of a tire.

(Prior Art) In general, the outer contour shape of the tread portion of pneumatic radial tires used for passenger cars, trucks, buses, etc. is almost the same for ultra-high-speed tires and general tires. Mainly, a plurality of circumferential grooves are formed.

The outer profile in the cross-sectional direction of a tread consisting of blocks and/or ribs usually exists on one circular arc, and it is also a The cross-sectional shape of a belt layer, such as an extensible belt, is also arranged substantially parallel to the outer contour of the tread.

By the way, in order to manufacture such a pneumatic radial tire, generally, a carcass ply is first wound around a cylindrical former, then bead rings are set on both sides of the former at the center of the circle, and the bead rings are placed on the bead rings. After placing the bead filler rubber on the carcass ply, both ends of the carcass ply are folded back axially outward, and a pair of side rubbers are attached to both sides of the carcass ply with a gap in the center.

Here, the carcass ply is usually made of cords made of fibers such as polyester, polyamide, rayon, and aromatic polyamide, which are aligned substantially in the direction of the rotational axis of the former, and consists of one or two plies of the rubberized layer. , consisting of at most three plies.

Next, the carcass portion is turned into a toroidal shape using a bladder, and a belt member and a tread member are sequentially pasted on the empty part between both side rubbers on the carcass ply, and a stating roller is applied to obtain a green tire.

The above-mentioned belt members and tread members are attached by plying a plurality of rubberized layers in which cords with high elastic modulus, such as metal cords, are arranged at a shallow angle to the circumferential direction, and sequentially plying the carcass so that the cords intersect with each other. Either the belt member and the tread member are formed into one piece in a separate process and both are attached to the crown part of the carcass ply in a separate process. be done.

A pneumatic radial tire is obtained by placing the thus formed green tire into a vulcanization mold having protruding ribs for forming circumferential grooves and vulcanizing it under high temperature and pressure using a conventional method. It will be done.

There are two types of molds used for the above-mentioned vulcanization and curing: a full mold and a split mold.A full mold is a mold that is divided into two parts at the tire's equatorial plane, and is used to mold the tire. Vulcanization and hardening are performed by covering the circumferential outer contour and heating it.

In addition, a split mold is a combination of multiple segments, usually 6 to 12 segments, each having a dividing surface in the direction in which the crown part is to be molded. The divided surfaces are combined and arranged to form an outer contour, and the mold is heated to perform vulcanization and hardening.

However, in recent years, particularly high-quality and high-performance tires have been in demand, so segment-type moldings, which have better performance such as uniformity and group cracking, are preferred than full-mold molds, which are more cost-effective. Types tend to be used frequently.

That is, FIGS. 4 and 5 are explanatory diagrams of cutting off the tire outer contour (crown part) forming part of one segment in a conventional multi-segment type vulcanization mold, and in the drawings, 1 indicates a mold segment. , 2 indicates a protruding bone, and 3 indicates a concave portion. In a tire vulcanized and molded using such a vulcanization mold, the protruding bone 2 contact portion is a circumferential groove of the crown portion, and the portion corresponding to the concave portion 3 is a circumferential groove of the crown portion. This corresponds to each section.

In this way, the tire vulcanized with the above-mentioned vulcanization mold is
A tread layer is formed in the crown portion of the tread layer in which protruding areas (ridges) consisting of blocks and/or ribs sandwich a plurality of circumferential grooves in parallel to the circumferential direction.

(Problem to be Solved by the Invention) However, as the above-mentioned conventional vulcanization mold material, aluminum, aluminum alloy, etc. are used, and each segment 1 is formed from the same single piece of mold, or The entire vulcanization mold is constructed by partially combining other materials.

That is, FIG. 4 shows an example in which each segment 1 is made of the same material, and FIG. 5 shows an example in which only the protruding bone 2 is made of a different material. For example, by using a harder material than other parts, the two protruding bones are prevented from being worn out, and the precision and durability of the mold are improved. For convenience, they were made of a single material with relatively low hardness.

By the way, there is generally a demand for forming stamps such as letters, patterns, figures, etc. on the ridges of tires, and a stamp section (4 in the drawing) for this purpose is formed in the recess of the vulcanization mold.

However, since the recess 3 of the mold segment is more depressed than other parts, not only is it difficult to engrave on this part, but also, as mentioned above, the recess 3 of the vulcanization mold has a relatively low hardness. Since it was formed from a single material, there was a problem in that the formed stamped portion 4 was easily worn away due to aging due to the use of the mold and cleaning of the mold, and sufficient durability could not be obtained.

The present invention was achieved as a result of studies aimed at solving the problems with the conventional vulcanization molds described above.

Therefore, an object of the present invention is to improve the abrasion resistance of the stamping part for forming characters, patterns, figures, etc. on the outer contour of the tire without sacrificing the convenience and moldability of the mold. The vulcanization mold of the present invention provides a vulcanization mold that includes a pair of left and right side rings for molding the sidewall of a tire, and a plurality of grooves extending in the circumferential direction at predetermined intervals in the axial direction. A mold is made mainly of segment parts divided into a plurality of parts in the circumferential direction to mold the crown part of the tire including the protruding bones of the protruding bones and the recess formed between these protruding bones. At least a part of the recessed part is made of a harder metal than the remaining molded part.

(Function of the invention) The vulcanization mold of the present invention has at least a part of the recess located between the two protruding bones in the segment formed of a metal harder than the remaining molded part, and this part has letters, patterns and Since the engraved part is provided for forming figures, etc., it is possible to prevent the engraved part from being worn out due to repeated use of the mold for a long time, cleaning, etc., and the abrasion resistance of the engraved part is greatly improved. can be improved.

Further, since the vulcanization mold of the present invention has a hard metal fitted into at least a part of the recess in the segment, the hard metal part can be formed as a separate part, and by stamping on this separate part, It is possible to simplify the marking work for the recesses, which has been complicated in the past.

Therefore, according to the vulcanization mold of the present invention, important characters, patterns, figures, etc. can be repeatedly formed on the ridge of a tire while maintaining excellent mold workability and moldability.

(Example) Hereinafter, the present invention will be described in detail with reference to the drawings using an example of a split mold.

As shown in FIG. 1, the vulcanization mold of the present invention has a pair of left and right side rings 1 for molding the sidewall of a tire.
The tire is mainly composed of a plurality of (nine in the drawings) segment parts 20 divided in the circumferential direction into which the crown part of the tire is to be molded.

In FIG. 1, the side ring 1o opens and closes in the vertical direction of the drawing, and each segment 2o opens and closes outward in the circumferential direction (for example, in the direction of the arrow in the drawing) to accommodate green tires.
It is designed to be vulcanized and molded.

As shown in FIGS. 2 and 3, each segment 20 includes a plurality of protruding bones 30 extending circumferentially at predetermined intervals in the axial direction and corresponding to the width of the tire, and a plurality of protruding bones 30 formed between these protruding bones. It includes a recessed portion 4o.

The protruding rib 3o corresponding to the circumferential direction of the tire is usually 2 to 15 mm, although it varies depending on the tire size or type of tire.
For example, a plurality of circumferential grooves parallel to the circumferential direction are formed in the tire tread by the protruding bones 3o.

Further, in FIGS. 2 and 3, T indicates a green tire or a vulcanized/molded tire.

Therefore, in the vulcanization mold of the present invention, at least a portion of the recess 40 in each segment 20 is provided with a portion (hereinafter referred to as the stamped portion 50) made of a harder metal than the remaining molded portion. It is characterized by

That is, most of the vulcanization mold of the present invention is made of metal such as aluminum or aluminum alloy, which has relatively low hardness and is easy to cast.
0 is made from a metal that is harder than other components, such as steel.

This stamped part 50 is formed separately from the vulcanization mold body in the form of a steel piece, for example, and is fitted into at least a part of the recessed part 40 in the segment 20, and then The vulcanization mold of the present invention can be obtained by fixing it to the mold body.

Appropriate characters, patterns, figures, etc. are engraved on the tire contacting surface 50' of the engraved part 50, so that the above-mentioned characters, patterns, figures, etc. are transferred and formed on the surface of the ridge part of the tire. It is configured as follows.

The stamping part 50 as a separate body can be easily engraved with characters, patterns, figures, etc., and is highly resistant to abrasion due to its high hardness, and is suitable for use in vulcanization molds. Since the markings are not easily worn out by repeated use or cleaning, clear letters, patterns, figures, etc. can be clearly marked on the tire over a long life.

Further, as another aspect of the vulcanization mold of the present invention, there is an example in which, like the recess 40, the protruding rib 30 is also made of a metal that is harder than the other constituent parts. According to this aspect, it is sufficient to attach the protruding ribs 30 formed separately to each segment of the mold body by means such as screwing, and since the protruding ribs themselves have high hardness and excellent wear resistance, Not only can the molding accuracy for forming the circumferential groove be improved, but also the protruding bone can be replaced depending on the depth and width of the circumferential groove to be formed, which is economically advantageous.

Note that the stamped portion 50 made of a hard metal with high hardness is
It is not necessary to provide it in all the segments 20 constituting the vulcanization mold, and it is sufficient to provide it only in the recesses 40 of the segments 20 corresponding to the portions where letters, patterns, and figures need to be formed on the ridge of the tire.

The vulcanization mold of the present invention having the above configuration is used to put a green tire into it and vulcanize it under high temperature and pressure using a conventional method, thereby producing a pneumatic radial tire with high marking accuracy and high efficiency. It can be obtained.

The effects of the vulcanization mold of the present invention will be further explained below using test examples.

(Test example) Using a vulcanization mold with the following conditions, tire size 185/60
An R14 pneumatic radial tire was manufactured.

Radial width of 9-segment tread portion = 176 - Height of protruding bone near, 9 mm 〃 Width: Average approx. 6 m 1 II 〃 Number: 6 Width of recess: Approx. 9 ms Mold body material Nialuminum (Hardness: AC4C, Hb-
55) However, in the recess of one segment, hardness: 82
5C, embedded with steel pieces from 121 to 156.

And, on the surface of the above piece, there is a BS mark (engraved height: 0
．． 4mm), and the same mark was transferred and formed on a part of the tire ridge.

Using the above vulcanization mold, we continued the vulcanization and molding work of green tires 10,000 times in a row, but the above stamp on the mold showed no wear at all, and by the 20,000th molding The BS mark of the tires obtained was also extremely important.

On the other hand, for comparison, we did not use the steel piece mentioned above, but made the entire mold of the same aluminum material, and used a mold with the same BS mark as above engraved on the concave surface of one segment. As a result of continuing the tire vulcanization and molding work 10,000 times, the edges of the above stamp on the mold were worn away, and the B of the tire obtained after the 20,000th molding.
The S mark lacked redness.

It is said that the cause of wear and tear on the vulcanization mold is more likely to be caused by cleaning the dirt on the vulcanization mold with glass beads or plastic beads than by the vulcanization molding process itself. Although the conventional vulcanization mold lost its appearance after 10 cleanings, the vulcanization mold of the present invention was extremely clear.

Upper air cleaning must be performed approximately every 2000 bottles.

[Effects of the Invention] As explained in detail above, the vulcanization mold of the present invention has at least a part of the recess located between the two protruding bones in the segment formed from a harder metal than the remaining molded part. Since an engraved part for forming characters, patterns, figures, etc. is provided in this part, it is possible to prevent the engraved part from being worn out due to repeated use of the mold for a long time, cleaning, etc. The wear resistance of the stamped part can be greatly improved.

Further, since the vulcanization mold of the present invention has a hard metal fitted into at least a part of the recess in the segment, the hard metal part can be formed as a separate part, and by stamping on this separate part, It is possible to simplify the marking work for the recesses, which has been complicated in the past.

Therefore, according to the vulcanization mold of the present invention, clear characters, patterns, figures, etc. can be repeatedly formed on the ridges of a tire while maintaining excellent mold workability and moldability.

[Brief explanation of drawings]

Fig. 1 is a perspective explanatory view showing the vulcanization mold of the present invention, Fig. 2 is an explanatory cross-sectional view taken along line A-A of the vulcanization mold of Fig. 1, and Fig. 3 is an enlarged cross-section of the main part of Fig. 2. 4 and 5 are cross-sectional explanatory diagrams of a tire outer contour (crown portion) forming portion of one segment in a conventional multi-segment type vulcanization mold. 10... Side ring 20... Segment 30... Protruding bone 40... Concave portion 50... Engraved portion

Claims (1)

[Claims] A tire that includes a pair of left and right side rings into which the sidewalls of the tire are to be molded, a plurality of protruding bones corresponding to grooves of the tire extending in the circumferential direction at predetermined intervals in the axial direction, and a recess formed between these protruding bones. The crown portion of the mold is formed mainly by a plurality of segments divided in the circumferential direction, and at least a part of the recess located between the two protruding bones in the segment is made of a harder metal than the remaining molded portion. A vulcanization mold characterized by comprising: