Patent Application
20120148702
The invention relates to the field of tire manufacturing, and more particularly to tire component manufacturing.
In tire manufacturing, numerous tire components are formed of a plurality of rubber parts. Rubber tire components such as the tire apex, sidewall, and tread are formed by an extrusion process. One type of extruder typically used in tire manufacturing is a screw extruder. The screw extruder typically has a long chamber with a screw centered in the channel, wherein the screw masticates the rubber. The end of the channel typically has a die having a hole formed therein. The shape of the hole dictates the cross-sectional shape of the rubber part to be made. The extruder pressure forces the rubber through the small die hole forming the part to be made in a continuous manner. The desired rubber part is obtained by cutting the extruded part to a given length.
Some rubber tire components can be more challenging to manufacture. An apex has a triangular cross-sectional shape that is extruded into a linear piece having the desired triangular cross-section. Depending upon the tire application, some apexes have triangular cross-sections which are tall and thin. Since the shape of the die mimics the shape of the desired rubber component, the die hole also has a thicker region and a much thinner region. The rubber tends to follow the path of least resistance, which means that the rubber does not want to flow into the thin region of the die. This can result in malformed apex articles that must be scrapped. Thus it is desired to have an improved die and method of manufacturing complex rubber articles.
“Aspect Ratio” means the ratio of a tire's section height to its section width.
“Axial” and “axially” means the lines or directions that are parallel to the axis of rotation of the tire.
“Bead” or “Bead Core” means generally that part of the tire comprising an annular tensile member, the radially inner beads are associated with holding the tire to the rim being wrapped by ply cords and shaped, with or without other reinforcement elements such as flippers, chippers, apexes or fillers, toe guards and chafers.
“Belt Structure” or “Reinforcing Belts” means at least two annular layers or plies of parallel cords, woven or unwoven, underlying the tread, unanchored to the bead, and having both left and right cord angles in the range from 17° to 27° with respect to the equatorial plane of the tire.
“Bias Ply Tire” means that the reinforcing cords in the carcass ply extend diagonally across the tire from bead-to-bead at about 25-65° angle with respect to the equatorial plane of the tire, the ply cords running at opposite angles in alternate layers
“Breakers” or “Tire Breakers” means the same as belt or belt structure or reinforcement belts.
“Carcass” means a laminate of tire ply material and other tire components cut to length suitable for splicing, or already spliced, into a cylindrical or toroidal shape. Additional components may be added to the carcass prior to its being vulcanized to create the molded tire.
“Circumferential” means lines or directions extending along the perimeter of the surface of the annular tread perpendicular to the axial direction; it can also refer to the direction of the sets of adjacent circular curves whose radii define the axial curvature of the tread as viewed in cross section.
“Cord” means one of the reinforcement strands, including fibers, which are used to reinforce the plies.
“Inner Liner” means the layer or layers of elastomer or other material that form the inside surface of a tubeless tire and that contain the inflating fluid within the tire.
“Inserts” means the reinforcement typically used to reinforce the sidewalls of runflat-type tires; it also refers to the elastomeric insert that underlies the tread.
“Ply” means a cord-reinforced layer of elastomer-coated, radially deployed or otherwise parallel cords.
“Radial” and “radially” mean directions radially toward or away from the axis of rotation of the tire.
“Radial Ply Structure” means the one or more carcass plies or which at least one ply has reinforcing cords oriented at an angle of between 65° and 90° with respect to the equatorial plane of the tire.
“Radial Ply Tire” means a belted or circumferentially-restricted pneumatic tire in which the ply cords which extend from bead to bead are laid at cord angles between 65° and 90° with respect to the equatorial plane of the tire.
“Sidewall” means a portion of a tire between the tread and the bead.
The invention will be described by way of example and with reference to the accompanying drawings in which:
The die assembly 100 of the present invention is shown in
It is important to note that the shape of the preformer hole 120 is an important aspect of the invention. As shown in
Variations in the present invention are possible in light of the description of it provided herein. While certain representative embodiments and details have been shown for the purpose of illustrating the subject invention, it will be apparent to those skilled in this art that various changes and modifications can be made therein without departing from the scope of the subject invention. It is, therefore, to be understood that changes can be made in the particular embodiments described which will be within the full intended scope of the invention as defined by the following appended claims.
