Process for building tyres for vehicle wheels

Patent metadata

Field	Value
Publication number	US-12220889-B2
Application number	US-202017595697-A
Country	US
Kind code	B2
Filing date	May 26, 2020
Priority date	May 30, 2019
Publication date	Feb 11, 2025
Grant date	Feb 11, 2025

Abstract

In a process for building tyres for vehicle wheels, at least one tread band ( 9 ) or other elastomeric component of a tyre ( 2 ) is made by applying at least one continuous elongated element ( 14 ) according to a plurality of turns (C) around a forming drum ( 15 ) rotating around a geometric rotation axis (X) thereof. The continuous elongated element ( 14 ) is made by the action of extruding a first material through an extrusion nozzle ( 16 ), to form an inner core ( 33 ) of said continuous elongated element ( 14 ) exiting from an outlet opening ( 18 ) of the extrusion nozzle ( 16 ). During the extrusion, a second material different from the first material is conveyed around the first material, at the extrusion nozzle ( 16 ) and upstream of the outlet opening ( 18 ), to form a coating layer ( 32 ) which entirely surrounds the inner core ( 33 ).

First claim

The invention claimed is:

1. A method for building tyres for vehicle wheels, wherein at least one elastomeric component of a tyre is made by applying at least one continuous elongated element according to a plurality of turns (C) around a forming drum rotating around a geometric rotation axis thereof;
wherein a method of making the continuous elongated element comprises:
extruding a first material, when a supply of the first material is activated, through an extrusion nozzle, to form an inner core of the continuous elongated element exiting from an outlet opening of the extrusion nozzle; and
during the extrusion, activating a supply of a second material different from the first material, for conveying the second material around the first material, at the extrusion nozzle and upstream of the outlet opening, to form a coating layer, wherein the coating layer surrounds the inner core;
wherein the second material is introduced into a second supply duct leading to an injection chamber arranged around a first supply duct axially converging into an outlet channel, the outlet channel longitudinally crossing the extrusion nozzle and leading to the outlet opening, the injection chamber flowing into the outlet channel through a radial intake slit extending along a closed line around the outlet channel, and
wherein the radial intake slit has a variable axial dimension along a peripheral development thereof.

2. The method of claim 1 , wherein during the extrusion of the first material, the supply of the second material is maintained for a time and then deactivated to continue extrusion of the first material in absence of the second material.

3. The method of claim 1 , wherein during the extrusion of the second material, the supply of the first material is maintained for a time and then deactivated for extruding the second material in absence of the first material.

4. The method of claim 1 , wherein an inlet section of the extrusion nozzle includes a non-planar profile in a plane orthogonal to the longitudinal axis of the extrusion nozzle.

5. The method of claim 1 , further comprising modulating a flow rate of the second material conveyed around the inner core to modify the thickness of the covering layer applied around the inner core.

6. The method of claim 5 , wherein the flow rate of the first material is modulated in conjunction with the flow rate modulation of the second material, to keep the overall flow rate of the first and second material substantially constant through the outlet opening.

7. The method of claim 1 , wherein during extruding, activating a supply of a third material different from the first material and from the second material, for conveying the third material around the first material, at the extrusion nozzle and upstream of the outlet opening, to form a covering layer surrounding the inner core.

8. The method of claim 7 , wherein during extruding, the supply of the second material is maintained for a time and then deactivated, for extruding the third material in absence of the second material.

9. The method of claim 7 , further comprising modulating a flow rate of the third material conveyed around the inner core to modify the thickness of the covering layer applied around the inner core.

10. The method of claim 9 , wherein the flow rate of the first material is modulated in conjunction with the flow rate modulation of the third material, to keep the overall flow rate of the first and third material substantially constant through the outlet opening.

Assignees

• Pirelli

Inventors

• Amurri Cesare Emanuele
• De Col Christian
• Cantu′ Marco
• Basilico Roger

Classifications

• B29L2030/002

  Treads · CPC title

• B29K2995/0005

  Conductive · CPC title

• B29K2105/0023

  improving electric conduction · CPC title

• B29D2030/3078

  the layers being applied being substantially continuous, i.e. not being cut before the application step · CPC title

• B29D30/62

  by extrusion or injection of the tread on carcass · CPC title