Mold for tire having an annular insert with a concentric groove

Abstract

A mold for vulcanizing and molding a tire, this tire having a tread delimited by two sidewalls, the mold having a ring for molding the tread of the tire and two shells for molding the sidewalls, the mold having an annular groove extending in a recessed manner in one of the shells and an insert housed in the groove, this insert including at least one groove which is concentric with the insert and provided with a section that decreases in the depthwise direction of the groove.

Claims

1. A mold for vulcanizing and molding a tire, the tire comprising a tread delimited by two sidewalls, the mold including a ring for molding the tread of the tire and two shells for molding the sidewalls, the mold including at least one annular groove extending in a recessed manner in one of the shells and an insert housed in the annular groove, wherein the insert is annular and has at least one groove which is likewise annular, is concentric with the insert and provided with a section that decreases in the depthwise direction of the at least one groove of the insert, the insert is formed from a plurality of insert parts that are positioned one after another in one of the at least one annular groove of the shell, at least one insert part is produced by laser sintering, the insert part having all or part of the at least one groove in the insert, and each insert part has contact surfaces for contact with adjacent insert parts, and at least two insert parts are connected together in a region of their contact surface, this connection being able to be broken in order to separate the two insert parts.

2. The mold according to claim 1, wherein the insert comprises a plurality of grooves.

3. The mold according to claim 1, wherein the shell includes a through-opening extending between the insert and the outside of the shell.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) Further features and advantages of the embodiments of the invention will become apparent from the following description, given by way of nonlimiting example, with reference to the attached drawings, in which:

(2) FIG. 1 schematically shows a view in cross section in a meridian plane of a part of a mold according to an embodiment of the invention;

(3) FIG. 2 schematically shows a perspective view of an annular insert suitable for the mold in FIG. 1 and produced according to a first embodiment of the invention;

(4) FIG. 3 schematically shows a face of an insert part from FIG. 2 connected to another insert part;

(5) FIG. 4 schematically shows a view in cross section in a meridian plane of a part of a mold according to the invention, having a through-opening that makes it easier to extract the insert.

(6) In the following description, elements which are substantially identical or similar will be denoted by identical references.

DETAILED DESCRIPTION OF THE SPECIFIC EMBODIMENTS

Definitions

(7) A tire means all types of resilient tread whether or not it is subjected to an internal pressure.

(8) The tread of a tire means a quantity of rubber compound delimited by lateral surfaces and by two main surfaces, one of which is intended to come into contact with a road surface when the tire is running.

(9) The sidewall of a tire means a lateral surface of the tire, said surface being disposed between the tread of the tire and a bead of this tire.

(10) The bead of a tire means a part of the tire that is intended to be seated on a wheel rim.

(11) A mold means a collection of separate molding elements which, when brought closer together, delimit a toroidal molding space 20 for vulcanizing and molding a tire.

(12) The equatorial plane means a plane perpendicular to an axis of revolution of the mold, separating this mold into two identical half-molds.

(13) The meridian plane means a plane containing the axis of revolution of the mold.

(14) As can be seen in FIG. 1, the mold 1 comprises a ring 3 intended for molding the tread of a tire and two shells 5 for molding the sidewalls. The mold 1 also comprises an annular groove 7 that extends around the circumference of the sidewall and is recessed into one of the shells 5. An insert 9 is mounted in a movable manner in the groove. A groove 11 is provided on the sidewall side of the insert. This groove 11 opens up the volume required to form a protuberance on the sidewall of the tire produced by means of this mold. The profile and the dimensions of the groove are provided as a function of the profile and the dimensions of the protuberance on the tire to be molded.

(15) As shown in the exemplary embodiment in FIG. 2, the insert 9 is advantageously formed from a plurality of insert parts 9a to 9h that are aligned angularly one after another so as to form an annulus with suitable dimensions for insertion in the annular groove 7. In this figure, both the profile and the position of the groove 11 provided in the insert 9 can easily be seen. The groove 11 and the insert 9 are advantageously concentric.

(16) FIG. 3 shows an elevation view of a side face of the insert part 9b, as seen from the part 9a. The interface between the two sections 9a and 9b produces a joining region with a contact surface 13.

(17) A bridge 15, or joining element, makes it possible to fix two adjacent parts of the insert 9 together. In this example, the bridge 15 is provided in the central region of the contact surface 13. In variants, a plurality of bridges can be provided. The profile and the surface of the bridges can vary depending on the embodiment. The bridges are advantageously provided during the manufacture of the insert, in particular when the insert is produced by laser sintering. In order to change an insert part, the bridge(s) connecting the parts in question are broken or cut. The section of the bridges is advantageously provided and dimensioned to make this operation easier. Specifically, even though the parts are separable by breaking the bridges when the insert is removed from the mold, mounting the insert in the mold, preferably with a tight fit, confers sufficient rigidity for the molding operations to be able to be carried out without risking breaking the bridges. Moreover, the insertion of the insert into the shell groove confers solid support for effectively withstanding the molding forces.

(18) In the alternative embodiment presented in FIG. 4, a through-orifice 10, such as a bore, provides communication between the outside of the mold and the inside of the mold. This orifice makes it possible to introduce a demolding tool from the outside of the mold in order to make it easier to extract the insert, either as a whole or for one or more insert parts. A plurality of orifices 10 can be distributed angularly around the circumference of the shell.

(19) The figures and their descriptions given above illustrate embodiments of the invention rather than limit it. In particular, the various embodiments of the invention have just been described in relation to a particular example in which the groove is V-shaped, narrowing away from the sidewall of the tire to be molded.

(20) Nonetheless, it is clear to a person skilled in the art that the embodiments of the invention may be extended to other embodiments in which, in the alternative, a different shape, such as a U-shape or W-shape, for example, is provided. According to yet other alternative embodiments, a plurality of concentric grooves can be provided in the insert.

(21) The verbs comprise and have do not exclude the presence of elements other than those listed in the claims. The word a/an preceding an element does not preclude the presence of a plurality of such elements.