Abstract:
A tread rubber includes a cap portion formed by a nonconductive rubber, a base portion formed by a nonconductive rubber, and a conductive portion formed by a conductive rubber. A rubber hardness of the cap portion is higher than a rubber hardness of the base portion. The base portion is segmented in a tire width direction. A rubber forming the cap portion is filled in a recess at a segmented position. The conductive portion has a first portion which is provided in an outer side of the segmented position and extends to an inner side in the tire diametrical direction from the ground surface, and a second portion which is provided continuously in the first portion and extends in the tire width direction so as to run into the side surface or the bottom surface of the tread rubber.
Abstract:
A tread forming step of forming a non-conductive tread rubber includes a first step of forming the tread rubber in such a manner that a shoulder portion becomes smaller in diameter than a finish cross sectional shape, a second step of setting up a conductive layer extending along a tire circumferential direction while alternately passing through a first position which is exposed to a tread surface of the shoulder portion, and a second position which comes into contact with a sidewall rubber in an outer side in a tire width direction than the first position, and a third step forming a finish cross sectional shape of the tread rubber by adding a non-conductive rubber to the shoulder portion of the tread rubber.
Abstract:
A pneumatic tire is equipped with at least a tread part, a sidewall part, a bead part, and a carcass extending from tread part through sidewall part to bead part, and provided with a breaker part on the outside of carcass in the radial direction of the tire. The volume resistivity of each of a tread rubber, a sidewall rubber, a breaker rubber, and a carcass rubber formed in the tread part, the sidewall part, the breaker part, and the carcass respectively is set to 1×1012 Ω·cm or more. A conductive layer having volume resistivity of 1×1011 Ω·cm or less is provided between a carcass ply constituting the carcass and the sidewall rubber and has an exposed part to the tire surface. A rubber cement layer contacting with at least a part of the exposed part of the conductive layer and at least a part of the region that becomes a grounding surface in the tread part to the road surface is provided.
Abstract:
A pneumatic tire is provided with an electrically conductive path extending continuously from a position in the rim contacting surface to a position in the ground contacting surface through a sidewall portion, wherein a sidewall rubber is a high-performance rubber compound and almost-insulative, having a volume resistivity of not less than 1×10^8 ohm cm. The electrically conductive path includes a helical path made of an electrically conductive rubber having a volume resistivity of not more than 1×10^7 ohm cm. The helical path is disposed axially inside the sidewall rubber and extends spirally around the tire rotational axis. Preferably, the tread rubber, clinch rubber and carcass topping rubber are also almost-insulative high-performance rubber compounds.
Abstract:
A method of providing an extruded tire tread (T) with anti-static properties. In this method, a pin (10) is coated with an electrically conductive material (M). The coated pin (10) pierces the tire tread (T) to form an opening (12) of the desired depth and then is withdrawn. During withdrawal of the pin (10), the material (M) remains in the pierced opening (12) so that a conductive body (14) is formed in the tire tread (T). The pin (10) can then be re-coated with the material (M) and the cycle repeated to produce a plurality of conductive bodies (14) in the tire tread (T).
Abstract:
A tread (14) of a tire (10) includes a tread rubber layer (16). The tread rubber layer (16) has a two-layer structure including a base layer (23) and a cap layer (24). The base layer (23) is provided with a comb-shaped convex portion (26). The convex portion (26) is formed like a circle extended in the circumferential direction of the tire (10). A plurality of convex portions (26) is arranged in the axial direction of the tire (10) and is protruded in a radial direction. At least a part of the convex portions (26) is exposed to a tread surface (17) when the tire (10) is unused (brand-new). The cap layer (24) contains silica and the base layer (23) does not contain the silica.
Abstract:
This invention relates to a pneumatic rubber tire which contains at least one electrically conductive cord extending from an external outer surface of its wheel-rim mounting surface rubber component to an internal electrically conductive tread base layer rubber component to provide a path of least electrical resistance, namely an electrically conductive path, between the outer tire wheel-rim mounting surface and the internal tire tread base layer. The electrically conductive cord is comprised of at least one electrically conductive metal filament (e.g. metal filament, carbon fiber or combination of metal filament and carbon fiber) spirally wound around a centrally disposed core of at least one organic fiber.
Abstract:
The invention concerns a process and apparatus for the coextrusion of rubber mixtures, comprising a main extruder (1) with an extrusion head (10) having at least two flow channels (14, 15), each for a rubber mixture (A, B), the channels opening into an extrusion orifice (18) through which the two rubber mixtures (A, B) are propelled. The extrusion orifice (18) is delimited by a first wall (111) and a second wall (161). The apparatus also comprises at least one micro-extruder (2) for a third rubber mixture (C), whose extrusion head (22) is provided at its end with a nozzle (23) passing through the two flow channels (14, 15) such that the third rubber mixture (C) is inserted into each rubber mixture (A, B) upstream from the extrusion orifice (18).
Abstract:
A pneumatic rubber tire with a sidewall having an outer visible layer of a rubber composition of a relatively high electrical conductivity, wherein the tire sidewall contains an internal rubber strip of relatively high electrical conductivity. Said internal rubber strip extends radially outward from a rubber chafer component of the tire to a tread base layer component of a rubber tire tread of a cap/base configuration, wherein said chafer and tread base rubber compositions are of a relatively high electrical conductivity. The rubber strip thereby provides a path of increased electrical conductivity relative to said outer visible layer of the tire sidewall extending from the tire chafer to the tread base layer tire components. In practice, the rubber strip is exclusive of the outer surface of the tire tread cap layer intended to be ground-contacting, preferably exclusive of the tire tread cap layer itself, and preferably exclusive of the outer surface of the tire chafer component intended to contact a rigid metal rim of a tire/rim wheel assembly.
Abstract:
The invention concerns a process and apparatus for the coextrusion of rubber mixtures, comprising a main extruder (1) with an extrusion head (10) having at least two flow channels (14, 15), each for a rubber mixture (A, B), the channels opening into an extrusion orifice (18) through which the two rubber mixtures (A, B) are propelled. The extrusion orifice (18) is delimited by a first wall (111) and a second wall (161). The apparatus also comprises at least one micro-extruder (2) for a third rubber mixture (C), whose extrusion head (22) is provided at its end with a nozzle (23) passing through the two flow channels (14, 15) such that the third rubber mixture (C) is inserted into each rubber mixture (A, B) upstream from the extrusion orifice (18).