Method for manufacturing a molding element of a mold for vulcanizing a tire

Abstract

A Method for manufacturing molding elements for molds is provided herein. The molds are used for molding tires provided with a tread with a circumferential arrangement of tread pattern elements. The method includes: a step consisting in aligning a plurality of basic linings; a step consisting in generating, from the basic tread circumference portion, an intermediate support; and obtaining an unfinished molding element from the intermediate support.

Claims

1. A method for manufacturing molding elements for molding tires provided with a tread with a circumferential arrangement of tread pattern elements, the method comprising the steps of aligning a plurality of basic linings made of flexible material so as to form a basic tread circumference portion, with each of the plurality of the basic linings corresponding to a pattern element of the circumferential arrangement of the tread of the tire that is to be molded; using the basic tread circumference portion formed by the basic linings, molding an intermediate support out of a non-metallic material such that the intermediate support has a surface that corresponds to the tread circumference portion; using the intermediate support, making an unfinished molding element that is made out of metal; and cutting the unfinished molding element into a plurality of molding elements, the plurality of molding elements being assembleable in a predetermined order to form a mold.

2. The method of manufacture according to claim 1, wherein the plurality of cut elements include an additional thickness of material, and further comprising a phase of machining the said additional thickness for finalizing the dimensions prior to assembly in the mold.

3. The method of manufacture according to claim 1, wherein the intermediate support is made in an intermediate mold.

4. The method of manufacture according to claim 3, wherein the basic linings extend one another in the intermediate mold.

5. The method of manufacture according to claim 3, wherein the basic linings in the intermediate mold are wedged in position using a wedge, the wedge having a different hardness from the flexible material.

6. The method of manufacture according to claim 1, wherein the intermediate support is made of a destructible material.

7. The method of manufacture according to claim 1, wherein the unfinished molding element is made of a reusable material.

8. The method of manufacturing according to claim 1, further comprising, prior to the aligning, producing a basic die from resin, to obtain corresponding basic linings.

9. The method of manufacture according to claim 1, wherein the basic lining is made of silicone.

10. The method of manufacture according to claim 9, wherein the basic lining is made of silastene.

11. The method of manufacture according to claim 1, wherein the aligning of the basic linings is performed on a flat or concave support.

12. The method of manufacture according to claim 1, further comprising a mold having a support on which a plurality of the molding elements are circumferentially aligned.

13. The method of manufacture according to claim 1, further comprising a tire obtained by molding and vulcanizing using the plurality of molding elements.

14. The method of manufacture according to claim 13, further comprising: a tread provided with a plurality of pattern elements arranged in a circumferential alternation, with each of the plurality of pattern elements of the circumferential arrangement corresponding to a pattern element of a basic lining.

Description

DESCRIPTION OF THE FIGURES

(1) Further features and advantages will become apparent from the following description given by way of non-limiting example with reference to the attached drawings in which:

(2) FIG. 1 schematically depicts the key elements for creating an intermediate support from an aligned row of basic linings;

(3) FIG. 2 is a schematic perspective view of one example of a basic lining;

(4) FIG. 3 is a schematic perspective view of one example of a semi-finished molding element;

(5) FIG. 4 is a schematic perspective view of one example of a segment 6 after cutting;

(6) FIG. 5 is a schematic perspective view of one example of a segment 6 after machining;

(7) FIG. 6 is a schematic perspective view of one example of a basic die.

(8) In the description that will follow, elements that are substantially identical or similar will be denoted by identical references.

DETAILED DESCRIPTION

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

(10) The tread of a tire means a quantity of rubber compounds delimited by lateral surfaces and by two main surfaces one of which is intended to come into contact with a roadway when the tire is being driven on.

(11) A destructible material means a material that is easy to remove after the intended element has been molded, by destroying it, such as by breaking it or by cutting it up for example.

(12) A reusable material means a material having mechanical properties of which allow it to be reused several times over in an industrial tire molding method.

(13) FIG. 2 illustrates an example of a basic lining 1 made of a flexible material such as silicone for example, and preferably from silastene. The lining has a substantially elongate profile with, at each of its ends, a securing member, preferably in the form of a dovetail.

(14) As shown in FIG. 1, a plurality of basic linings 1 are aligned transversely one against the other to form a basic tread circumference portion 2. In order to keep the basic linings correctly assembled against one another, one or more supports such as wedges, made of a material of a hardness higher than that of the linings, are provided, for example on each side of the linings located at the lateral ends.

(15) A cradle-shaped intermediate mold 4 acts as a support for the linings. The resulting assembly means that an intermediate support 3, corresponding to the tread circumference portion, can be molded. This intermediate support 3 is advantageously made of a destructible material such as plaster.

(16) FIG. 3 illustrates the result of the next step, which consists in creating an unfinished molding element 5 for a tire mold. An intermediate support 3 is used for that so as to create an unfinished molding element by molding. After this molding, the intermediate support 3 used is destroyed to release the newly molded component. As this is an element that is likely to be used numerous times over in the production phases, the unfinished element is made of a reusable material made from a light metal alloy such as aluminium. That material also has the advantage that it can be machined.

(17) FIG. 4 shows the result of the subsequent step consisting in cutting the semi-finished molding element into a plurality of cut molding segments 6 or elements. The cutting is advantageously performed using a very high pressure water jet cutting machine. In order to carry out this cutting, an additional thickness of material 10 is provided in the design of the components on the faces of the lining. This additional thickness 10 is removed during the water jet cutting and/or during a subsequent machining phase in which the components are machined to the required final size and shape.

(18) FIG. 5 illustrates the machined segments 8 obtained during the step of machining the segments 6. In this step, each of the segments 6 is machined to remove the zones of material that are not needed for the subsequent operations and/or to add additional patterning or detail of use in the molding of the tires.

(19) FIG. 6 shows a prior step involving creating a basic die 7 or jig, preferably using resin. This step is performed in a way known per se and serves to form a component the shape of which is the negative of one of the segments 6.