Device for producing a tread for a vehicle tire

Abstract

A tread for a vehicle tire has an electrically conducting layer axially inside a portion of a first, radially outer rubber layer of the tread. The electrically conductive layer extends from a second, radially inner rubber layer of the tread on the radially inner side of the tread rubber material up to a ground contact surface of the tread. During the tire build-up, an accumulation of rubber material of higher electrical conductivity is built on a first rubber layer of higher electrical conductivity. The accumulation is formed into a ridge web and then less-conductive rubber is laid laterally next to the web, such that the web of rubber material reaches up to the ground contact surface in the finished vehicle tire. The web is shaped by forming rollers, by baffles, or by a forming ring with a corresponding shape.

1 . A device for producing a tread of a vehicle tire, the tread having a radially outer rubber layer, a radially inner rubber layer, and an electrically conductive layer disposed axially inside a portion of the radially outer rubber layer and extending from the radially inner rubber layer up to a ground contact surface of the tread, the device comprising:
 a building body rotatably mounted about an axis of rotation for building up rubber layers;   a drive connection for rotating said building body about the axis of rotation;   means for positioning and laying rubber material on the building body;   means for shaping built-up accumulations of rubber material on said building body and configured to form therefrom a web of rubber material extending from the radially inner rubber layer to the ground contact surface of the tread; and   means for laying the radially outer rubber layer laterally adjacent the web of rubber material.   
     
     
         2 . The device according to  claim 1 , wherein said shaping means are configured for shaping the accumulation of rubber material of higher electrical conductivity into a web with a cross-sectional contour tapering outwardly in a radial sense in its cross-sectional planes containing the axis of the vehicle tire. 
     
     
         3 . The device according to  claim 1 , wherein said drive connection is configured to rotate said building body about an axis of rotation while said positioning and laying means build up the material on a building surface of said building body. 
     
     
         4 . The device according to  claim 3 , wherein said building body is a building drum. 
     
     
         5 . The device according to  claim 3 , wherein said building body is a toroidal building core. 
     
     
         6 . The device according to  claim 3 , wherein said building surface is part of a solid surface. 
     
     
         7 . The device according to  claim 3 , wherein said building surface is part of an elastic surface. 
     
     
         8 . The device according to  claim 3 , wherein said building surface is a surface of an inflated bladder. 
     
     
         9 . The device according to  claim 1 , wherein said shaping means is a contoured shaping body. 
     
     
         10 . The device according to  claim 9 , wherein said shaping body is a baffle configured to be moved laterally and vertically towards the accumulation of material and to be held substantially stationary as the accumulation of material is moved past said baffle. 
     
     
         11 . The device according to  claim 1 , wherein said shaping means is a forming roller configured to be moved laterally and vertically towards the accumulation of material and to be biased against the accumulation of material as the accumulation of material is moved past said forming roller. 
     
     
         12 . The device according to  claim 1 , wherein said shaping means is a forming ring configured to be brought up to the accumulation of material coaxially and radially outside the first rubber layer, said forming ring including an annular stop for deforming the accumulation of material over the entire circumference of the first rubber layer.