Mold for tire having an annular insert for molding a tread pattern

Abstract

A mold for vulcanizing and molding a tire, this tire including a tread delimited by two sidewalls, the mold including a ring for molding the patterns of the tread of the tire and two shells for molding the sidewalls, the mold including an annular groove extending in a recessed manner in one of the shells and an insert housed in the groove, this insert having tire-molding surface features, characterized in that the molding surface features of the insert include tire tread pattern elements extending in line with the patterns of the tread.

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 patterns of the tread of the tire and two shells, separate from the ring, for molding the sidewalls, an annular groove extending in a recessed manner in one of the shells and an insert housed in the groove, the insert having tire-molding surface features, wherein the molding surface features of the insert include tire tread pattern elements extending in line with the patterns of the tread, and the insert is formed from a plurality of insert parts that are positioned one after another in the annular groove, 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, the connection being configured to be broken in order to separate the two insert parts.

2. The mold according to claim 1, wherein the tire-molding surface features are positioned substantially at a junction between the shell and the ring.

3. The mold according to claim 1, wherein the tire-molding surface features are positioned substantially along an entire length of the shell.

4. The mold according to claim 1, wherein each insert part has a molding surface configured to be in contact with the tire, and at least two insert parts have different molding surface features.

5. The mold according to claim 1, wherein at least one insert part is produced by laser sintering, the insert part having all or part of the molding surface features of the insert.

6. The mold according to claim 1, wherein at least one insert part is produced from cast aluminium.

7. The mold according to claim 1, wherein the shell comprises 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. 1A schematically shows a view in cross section of a mold provided with an annular insert produced according to a first embodiment of the invention;

(3) FIG. 1B schematically shows a view in cross section of a mold provided with an annular insert produced according to a second embodiment of the invention;

(4) FIG. 2 schematically shows a perspective view of an example of an annular insert according to an embodiment of the invention;

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

(6) FIG. 4 schematically shows a view in cross section in a meridian plane of a part of a mold according to an embodiment of the invention, showing an opening that allows access to the insert from outside the mold.

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

DETAILED DESCRIPTION OF SPECIFIC EMBODIMENTS

Definitions

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

(9) 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.

(10) 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.

(11) A tread pattern means the volumetric and surface arrangements of rubber compounds at the external surface of the tire, said arrangements being intended to ensure contact with the roadway and having a shape for adapting the operational performance of the tire. The tread patterns also confer an aesthetic appearance on the tread or some other region of the tire, such as the sidewalls.

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

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

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

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

(16) 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 removable manner in the groove. The insert 9 has tire-molding surface features. These forming/molding elements are provided so as to position the tread patterns on the region of the sidewall of the tire to be molded, or to confer a particular aesthetic appearance, and/or to provide elements for protecting the sidewalls on the tire produced.

(17) In an exemplary embodiment in FIG. 1A, the tire-molding surface features 11 are positioned substantially at the junction between the shell and the ring.

(18) In an exemplary embodiment in FIG. 1B, the tire-molding surface features 11 are positioned substantially along the entire length of the shell.

(19) Other, intermediate positions can also be provided. It is also possible to provide a plurality of inserts at one and the other of these positions.

(20) As shown in an exemplary embodiment in FIG. 2, the insert may be 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.

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

(22) 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 alternative embodiments, 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 is/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.

(23) In an 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.

(24) According to various alternative embodiments that are not illustrated, at least two insert parts have different dimensions, in terms of width and/or of height.

(25) 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.