Patent Application
20220185019
The invention relates generally to tires and more particularly to heavy duty tires, such as truck, bus or aircraft tires.
Aircraft, truck or bus tires are typically retreaded in order to reuse the large and complex tire carcass multiple times. However, the treads of truck, bus or aircraft tires may be subject to frequent punctures from stones or other sharp objects in the road or runway surface. The frequency and severity of punctures may cause the tire carcass to be scrapped. Cut protector belts are typically used to try and prevent the carcass from being damaged. However, cut protector belts are often not stiff enough to prevent the damage to the carcass. The sharp object tends to move the belt out of the way in order to pierce the carcass.
Thus, a cut protector belt that has improved cut resistance to foreign object damage, is desired. The improved cut protector belt can be used on new or retreaded tires to improve the service life of the tire carcass.
The invention provides in a first aspect a tire having a cut protector belt located radially outward of a main belt structure, wherein the cut protector belt is a structure that has 1 or multiple layers of cord formed below the tread and above the primary belt reinforcing structure. This structure is formed a ribbon of parallel cords having 1 to 20 cords in each ribbon and laid up in repeating wave pattern, with an average angle of approximately 0 degrees.
The invention provides in a second aspect a tire having a jointless cut protector belt, wherein the jointless cut protector belt is continuously wound using a strip of one or more reinforcement cords, wherein the strip of one or more reinforcement cords is wound in a sine wave pattern.
The invention provides in a third aspect a tire having a jointless cut protector belt, wherein the jointless cut protector belt is continuously wound using a strip of one or more reinforcement cords, in a wavy pattern that extends in the circumferential direction.
The invention provides in a fourth aspect a tire having a jointless cut protector belt that is continuously wound using a strip of one or more reinforcement cords, wherein the one or more reinforcement cords are formed of aramid, nylon or a blend thereof.
“Aspect ratio” of the cord means the ratio of its height (H) to its width (W) multiplied by 100 percent for expression as a percentage.
“Axial” and “axially” means lines or directions that are parallel to the axis of rotation of the tire.
“Chafer” is a narrow strip of material placed around the outside of a tire bead to protect the cord plies from wearing and cutting against the rim and distribute the flexing above the rim.
“Circumferential” means lines or directions extending along the perimeter of the surface of the annular tread perpendicular to the axial direction.
“Equatorial Centerplane (CP)” means the plane perpendicular to the tire's axis of rotation and passing through the center of the tread.
“Footprint” means the contact patch or area of contact of the tire tread with a flat surface at zero speed and under normal load and pressure.
“Groove” means an elongated void area in a tire dimensioned and configured in segment for receipt of an air tube therein.
“Lateral” means an axial direction.
“Lateral edges” means a line tangent to the axially outermost tread contact patch or footprint as measured under normal load and tire inflation, the lines being parallel to the equatorial centerplane.
“Radial” and “radially” means directions radially toward or away from the axis of rotation of the tire.
“Rib” means a circumferentially extending strip of rubber on the tread which is defined by at least one circumferential groove and either a second such groove or a lateral edge, the strip being laterally undivided by full-depth grooves.
“Sipe” means small slots molded into the tread elements of the tire that subdivide the tread surface and improve traction, sipes are generally narrow in width and close in the tires footprint as opposed to grooves that remain open in the tire's footprint.
“Tread element” or “traction element” means a rib or a block element defined by a shape with adjacent grooves.
“Tread Arc Width” means the arc length of the tread as measured between the lateral edges of the tread.
“Zigzag belt reinforcing structure” means a belt structure formed of at least two layers of cords interwoven together wherein a ribbon of parallel cords having 1 to 20 cords in each ribbon are laid up in an alternating pattern extending at an angle typically between 5° and 45° between lateral edges of the belt, and more preferably between 3 and 11 degrees, and most preferably between 5 and 11 degrees.
The invention will be described by way of example and with reference to the accompanying drawings in which:
A belt package 40 is arranged between the carcass 31 and the tread rubber 36 and is comprised of one or more belt plies 50,52, 54 preferably the radially innermost belts which are located near the carcass 31. Preferably, the one or more belt plies 50,52,54 are low angle belts, with a belt angle of 10 degrees or less, more preferably with a belt angle of 5 degrees or less. Preferably, the one or more low angle belts 50,52,54 increase in width from the radially innermost belt 50 to the radially outermost belt 54.
The belt package preferably includes one or more zigzag belt structures 62,64,66 located radially outward of the low angle belts 50,52,54. Each of the radially outer zigzag belt structures is formed by winding a rubberized strip 43 of one or more parallel reinforcement cords 46 generally in the circumferential direction while being inclined to extend between side ends or lateral edges 44 and 45 of the layer forming a zigzag path and conducting such a winding many times while the strip 43 is shifted at approximately a width of the strip in the circumferential direction so as not to form a gap between the adjoining strips 43. The strip of reinforcement cords preferably has a width W, W being in the range of 0.2 to 1.5 inches. It is preferable that the strip width W should be 1.0 inch or less to facilitate bending to form the zigzag paths of the inner and outer layers 41, 42.
The belt package may further include a top belt or cut protector belt 100 that is the radially outermost belt. The cut protector belt 100 is shown in
The reinforcement cords of the strip may comprise one or more parallel reinforcement cords made of nylon, nylon 6,6 or aramid reinforcement cords. Preferably, the reinforcement cord is aramid having a high twist construction. Preferably, the aramid cord construction is 3000/1/3 dtex with 6 twists per inch. Preferably, the reinforcement cords of the strip are high modulus cord reinforcements, such as hybrid or merged cords of nylon and aramid. More preferably, the cord construction is 3000 d/2 aramid and 1680 d/1 nylon. Preferably, the strip of reinforcement cords used to form the cut protector belt ranges in width from about 0.25 to about 0.5 inches, and has 4-10 number of reinforcement cords.
The cut protector belt 100 preferably has a width which extends from a first shoulder to a second shoulder, i.e., full belt width. Preferably, the cut protector belt width is 1.5-2 inches inboard from the widest belt width to minimize durability risk.
The period ranges from 50 mm to 100 mm and more preferably from 75 mm to 100 mm. While it is desired to minimize the period, it is constrained due to the application method. The % extra cord ratio referred to herein, and shown in
The amplitude of the sine wave affects the extra cord %. As the amplitude increases, so does the extra cord %. Preferably, the sine wave amplitude ranges from 1-5 mm, and more preferably, from 2. mm to 3.5 mm, and more preferably from 2.5 mm to 3 mm. Amplitudes exceeding 5 mm can lead to unfavorable tire appearance.
The turn radius is minimized up to the limit of strip buckling. The turn radius is defined as the radius of the circle traversing between three points on the sine wave 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.
| Number | Date | Country | |
|---|---|---|---|
| 63126049 | Dec 2020 | US |
