Molding element having cutting means for molding and vulcanizing a tire tread

Abstract

The disclosure relates to a molding element of a mold for molding and vulcanizing a tire tread, this tread comprising a tread surface intended to come into contact with the ground when the said tire is running. The molding element includes a rib for molding a groove in the tire tread, the rib being a rounded end.

Claims

1. A molding element of a mold for molding and vulcanizing a tire tread, comprising: a rib being able to be molded to a groove in the tire tread, the rib having a rounded end, two cutting means positioned on either side of the rib at a predetermined distance from the rib, each of the two cutting means including a cutting edge, the cutting edge forming an acute angle, a plurality of lamellas positioned between the rib and the cutting means, the plurality of lamellas being shallower than the rib, the rib having a direction of extension X and each lamella having a direction of extension Y, the direction of extension Y of the lamella makes an angle with the direction of extension X of the rib, the angle being less than 20.

2. The molding element according to claim 1, wherein there is a minimum distance D between the rib and the nearest lamella, the minimum distance is being at least 1 mm.

3. The molding element according to claim 1, wherein the angle is less than or equal to 10.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) Other features and advantages of the disclosure will emerge from the following description, given by way of non-limiting example, with reference to the attached drawings in which:

(2) FIG. 1 schematically depicts a molding element according to the disclosure at a first step;

(3) FIG. 2 schematically depicts the molding element of the FIG. 1 at a second step;

(4) FIG. 3 illustrates the molding element of FIG. 1 in another view

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

DETAILED DESCRIPTION

(6) FIG. 1 depicts a molding element 1 according to the disclosure at a first step. The molding element 1 comprises a rib 5 and two cutting means 7 positioned on either side of the rib 5 at a certain distance from this rib. The cutting means 7 are able to cut a cover layer 11 that covers a green tire 13. The rib 5 itself will mold a groove in the tread and at the same time guide part of the cover layer into this groove thus molded.

(7) More particularly, the rib 5 comprises a rounded end. The cutting means 7 comprises a cutting edge 8, the cutting edge making an acute angle. In a preferred embodiment, the acute angle is lower than or equal to 60. In a variant, the acute angle is lower than or equal to 35. In other variant, the acute angle is lower than or equal to 20. Indeed, the molding element 1 comprises a plurality of lamellas 9 positioned between the rib 5 and the cutting means 7, the lamellas being shallower than the rib. More particularly, the lamella have a height between 0.1 and 0.8 mm, a width between 0.1 and 0.8 mm and the pitch of the lamellas being between 0.5 and 3.0 mm.

(8) FIG. 2 depicts the molding element 1 of the disclosure at a second step. A this step, the molding element 1 and the green tire 9 move closer to one another. This movement is, for example, initiated by a membrane not depicted) in the mold. Under the action of a quantity of pressurized steam, this membrane swells and pushes the green tire towards the molding element 1. At the step of FIG. 2, the cutting means 7 have cut the cover layer 11. The rib 5 is molding a groove in the tread and at the same time guide part of the cover layer into this groove, The disclosure proposes to maintain a minimum distance D between the rib 5 and the nearest lamella 9. Thanks to this minimum distance, we limit unexpected trapping of the covering material by the lamella, More particularly, the distance D is at least 1 mm.

(9) FIG. 3 illustrates the molding element 1 of FIG. 1 in another view. In this view, the rib 5 has a direction of extension X and each lamella has a direction of extension Y. The direction of extension Y of the lamella makes an angle with the direction of extension X of the rib, this angle being less than 20. In a preferred embodiment, the angle is less than or equal to 10.

(10) The disclosure is not restricted to the examples described and depicted and various modifications can be made thereto without departing from its scope.