JP2951435B2 - Tire mold - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a tire mold used for molding and vulcanizing a tire.

[0002]

2. Description of the Related Art In general, in forming and vulcanizing a radial tire, there is a stretching of a raw cover, and therefore, a two-piece mold can be used. In order to prevent damage due to the groove of the mold and the knife blade, it is formed by a split mold.

Conventionally, a split mold has a plurality of tread segments which are divided in the circumferential direction into the upper and lower mold bodies so as to be openable and closable. (See Japanese Patent Application Laid-Open No. 58-211438).

[0004]

However, the conventional split mold has a problem that the structure is complicated and the entire mold is large, so that the press must be larger than necessary. . The present invention has been made in view of the above-described situation, and the object is to reduce the size of the entire mold with an extremely simple structure, without using an unnecessarily large press. Moreover, it is an object of the present invention to provide a tire mold in which the mold replacement operation is simple and the production cost can be reduced.

[0005]

According to the present invention, the following technical measures have been taken in order to achieve the above object. That is, the present invention relates to a tire mold including an upper mold and a lower mold, in each of the upper and lower mold main bodies, a tread segment divided into a plurality of pieces in a circumferential direction thereof has a sliding guide body on an outer peripheral side thereof. And the upper and lower tread segments are held in the respective mold bodies by springs.

Further, according to the present invention, when each of the upper and lower tread segments exerts a certain force or more toward the upper and lower mold parting surfaces,
It is characterized in that it is slid and opened respectively on the upper and lower mold parting surfaces, and is retracted and restored when the force becomes less than a certain level.

[0007]

According to the present invention, when the raw tire is inserted into the upper and lower molds, each tread segment is held in each of the upper and lower molds by the biasing force of the spring. Held in the mold. After the vulcanization of the tire is completed, when the upper and lower molds are opened, each upper and lower tread segment is restrained by the tread surface of the molded tire, and the upper and lower tread segments are vertically moved until the split surfaces of the upper and lower mold split surfaces are in close contact. Without opening, it slides along the slide guide body with respect to the upper and lower mold bodies, moves slightly in the radial direction (radial direction), and separates from the tread surface of the molded tire. At this time, since the restraining force by the tread surface of the tire is equal to or less than a certain value, each tread segment is pulled into each of the upper and lower dies by the biasing force of the spring, restored, and held in that state. Therefore, the molded and vulcanized tire can be easily removed from the mold without the tread pattern portion being caught or damaged by the ridge of the tread segment.

[0008]

Embodiments of the present invention will be described below with reference to the drawings. The tire mold according to the present invention includes an upper mold 1 and a lower mold 2, but the structure of the lower mold 2 is different from that of the upper mold 1.
Since the structure is the same as that of the upper mold 1, the description is omitted, and the structure of the upper mold 1 will be mainly described. It is shown attached.

FIG. 1 shows a mold closed state. Reference numeral 3 denotes a mold body, a sidewall mold 4 is fixed to the inner surface of the mold body by screws or the like, and an inner peripheral surface 5 of the mold body 3 has a mold dividing surface 6. The inner side is a tapered inner surface that is inclined so as to have a large diameter. Reference numeral 7 denotes a tread segment divided into a plurality of pieces (8 to 9 pieces) in the circumferential direction, the outer peripheral surface 8 of which is the same taper surface as the inner peripheral surface 5 of the mold body 3, and the inner peripheral surface has A tread groove ridge 9 (see FIG. 3) protrudes.
A guide groove 10 in the form of a key groove is formed in the outer peripheral surface 8 of each segment 7 in parallel with the tapered surface (oblique with respect to the axial direction), and as shown in FIG. 11 (or a groove) is provided in parallel with the tapered surface, a spring 12 is fitted into the spring fitting hole 11, and the inner end 13 is fixed to each segment 7.

On the inner peripheral surface 5 of the mold body 3, a slide key-shaped slide guide 14 which is loosely fitted in the groove 10 corresponding to the guide groove 10 of the segment 7 is secured by a bolt 15. It is fixed. A spring support rod 16 is fixed to the upper and lower wall surfaces of the mold body 3 near the inner peripheral surface 5 so as to be parallel to the inner peripheral surface 5 corresponding to the spring insertion holes 11 of the segments 7. An outer end 17 of the spring 12 fitted on the support rod 16 is fixed to the mold body 3.

Therefore, each segment 7 is pulled into the mold body 3 by the spring 12 fitted therein, and the closed state is maintained as shown in FIG. When a force exceeding a certain level is applied (in the direction shown by the arrow (a)), the spring 12
(A), each segment 7 is opened by sliding in the direction shown by (a), and when the force against the urging force becomes less than a certain value, each segment 7 is moved by an It retreats and restores in the direction shown in (b), and the closed state is maintained.

In the above embodiment, in the empty state before the raw tire is inserted, both the upper and lower dies 1, 2 are closed and open as shown in FIG. No force acts in the direction of the mold splitting surfaces 18, 18a, and the segments 7, 7a are held in the mold main bodies 3, 3a by the urging forces of the springs 12, 12a. Therefore, the upper and lower dies 1 and 2 are opened, the green tire is inserted, and the molding and vulcanization are performed by applying pressure and heat. After the vulcanization of the tire is completed, the upper and lower dies 1, 2 are opened, and as shown in FIG. 3 and FIG.
3a and the sidewall molds 4, 4a are both separated from the molded tire T, but each of the upper and lower tread segments 7, 7a is
Along with the sliding guides 14a of 3a, it slides with the tire T in the direction shown by the arrow (a) in FIG. That is, each segment
7, 7a are restrained by the tire T because the protruding ridges 9, 9a on the inner peripheral surface thereof are fitted in the grooves G on the tread surface of the tire T, and a certain amount or more in the direction shown by the arrow (a) in FIG. Is applied, the sliding surfaces 18 and 18a slide against the urging force of the springs 12 and 12a while the mold surfaces 18 and 18a are in close contact with each other. The segments 7, 7a are opened in the radial direction (radial direction of the tire T) while moving in the direction shown by the arrow (a) in FIG.
Is released from the groove G of the tire T, that is, when the force acting on each segment 7, 7a becomes equal to or less than a certain value, the restraint by the tire T is released, and each segment 7, 7a is
Due to the biasing force of 2a, the mold is automatically drawn into the mold bodies 3, 3a, retreats and restores, and is held in the state shown in FIGS. Thus, the molded and vulcanized tire T can be easily removed from the mold without the grooves or the like of the tread pattern portion being caught or damaged by the ridges 9, 9a of the segments 7, 7a. Can be.

Each of the segments 7, 7a in the upper and lower dies 1, 2 from which the molded tire T is taken out is held in a state in which a green tire can be inserted. The present invention is not limited to the above-described embodiment.For example, grooves can be used instead of the insertion holes 11, 11a of the springs 12, 12a, and the spring supports 16, 16a are formed into a cylindrical body in a cylinder. The springs 12, 12a can be fitted and fixed. Further, guide grooves may be provided on the mold bodies 3, 3a side, and sliding guides 14, 14a may be provided on each segment 7, 7a.

[0014]

As described above, according to the present invention, in a tire mold including an upper mold and a lower mold, a plurality of circumferentially divided tread segments are provided in upper and lower mold bodies. It is characterized by being fitted slidably in the axial direction and the radial direction via a slide guide on the outer peripheral side, and each of the upper and lower tread segments is held in each mold body by a spring. The structure is extremely simple, the opening and closing operation of each segment is smooth and reliable, the whole mold can be downsized, the press does not need to be unnecessarily large, and the rubber is engaged by the upper and lower mold split surfaces of the tread segment. There is no occurrence of overspew, the quality of tires can be improved and the mold manufacturing cost can be reduced, and the mold replacement work can be easily performed.

[Brief description of the drawings]

FIG. 1 is a partially cutaway sectional view showing a closed state of a mold according to an embodiment of the present invention.

FIG. 2 is an enlarged sectional view of a main part showing holding means in a mold main body of each tread segment in FIG. 1;

FIG. 3 is a partially cutaway sectional view showing a state in which the mold is being opened after completion of tire molding vulcanization according to the embodiment of the present invention.

FIG. 4 is an enlarged sectional view of a main part showing a state of holding means in a mold main body of each tread segment in FIG. 3;

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Upper mold 2 Lower mold 3 Mold main body 3a Mold main body 7 Tread segment 7a Tread segment 10 Guide groove 10a Guide groove 12 Spring 12a Spring 14 Sliding guide body 14a Sliding guide body 18 Molding surface 18a Molding surface

Claims (2)

(57) [Claims] In a tire mold comprising an upper mold and a lower mold, a plurality of tread segments divided into a plurality in the circumferential direction in respective upper and lower mold main bodies via a sliding guide body on the outer peripheral side thereof. A tire mold slidably fitted axially and radially, and upper and lower tread segments held in respective mold bodies by springs. 2. The upper and lower tread segments slide open toward the upper and lower mold split surfaces when a predetermined force or more is applied to the upper and lower mold split surfaces, respectively, and retreat and restore when the force becomes less than a certain force. The tire mold according to claim 1, wherein: