Tire with cut protection belt structure

Abstract

To provide a tire with an improved cut protector belt which improves the service life of a tire carcass.SOLUTION: A tire has a cut protector belt located radially outward of a main belt structure. The cut protector belt has a zigzag belt structure formed by winding a monofilament cord from a first lateral edge to a second lateral edge in a zigzag manner so as to form an integrally formed dual (two) layer of cords, where the cross-sectional shape of the monofilament cord is not round.SELECTED DRAWING: None

Description

[Technical Field]

[0001] FIELD OF THE INVENTION The present invention relates generally to tires, and more particularly to heavy duty tires such as truck, bus or aircraft tires. [Background technology]

[0002] Aircraft, truck, or bus tires are commonly retreaded, allowing the large, complex tire carcasses to be reused multiple times. However, the treads of truck, bus, or aircraft tires are subject to frequent punctures from stones or other sharp objects on road or runway surfaces. The frequency and severity of punctures can result in the tire carcass being discarded. Cut protection belts are typically used to prevent damage to the carcass. However, cut protection belts are often not hard enough to prevent damage to the carcass. Sharp objects tend to move the belt out of the way to puncture the carcass. Therefore, an improved cut protection belt is desirable, which can be used on new or retreaded tires and improves the service life of the tire carcass. Summary of the Invention

[0003] In a first aspect, the present invention provides a tire having a cut protection belt located radially outward of a main belt structure, the cut protection belt being a zigzag belt structure, the zigzag belt structure being formed by winding a monofilament cord in a zigzag pattern from a first lateral end to a second lateral end to form two integrally formed cord layers, the cross-sectional shape of the monofilament cord being non-circular, preferably a rectangle sandwiched between two semicircles.

[0004] (definition) The "aspect ratio" of a cord means the ratio of its height (H) to its width (W) multiplied by 100 percent to express as a percentage.

[0005] "Axial" and "axially" mean lines or directions parallel to the axis of rotation of the tire.

[0006] "Chafers" are narrow strips of material placed around the outside of the tire bead to prevent wear and cut of the cord plies against the rim and to distribute flexing above the rim.

[0007] "Circumferential" means lines or directions extending along the perimeter of the surface of the annular tread perpendicular to the axial direction.

[0008] "Equatorial Center Plane (CP)" means the plane perpendicular to the tire's axis of rotation and passing through the center of its tread.

[0009] "Footprint" means the contact patch or area of ​​contact between the tire tread and a flat surface at zero speed and under normal load and air pressure.

[0010] "Groove" means an elongated void area partially sized and configured in a tire to receive an air tube therein.

[0011] "Lateral" means axially.

[0012] "Lateral Edge" means a line tangent to the axially outermost tread contact patch or footprint as measured under normal load and tire inflation, the line being parallel to the equatorial centerplane.

[0013] "Single fiber" means a cord having only one fiber.

[0014] "A rectangle sandwiched between two semicircles" means a cross-sectional shape having two opposing semicircles connected by parallel lines tangent to their endpoints.

[0015] "Radial" and "radially" mean directions radially toward or away from the axis of rotation of the tire.

[0016] "Rib" means a circumferentially extending strip of rubber on a tread defined by at least one circumferential groove and either a second such groove or a lateral end, the strip not being divided laterally by the deepest groove.

[0017] "Sipe" means small slots molded into the tread elements of a tire that subdivide the tread surface and improve traction; sipes are generally narrow and close in the tire's footprint, as opposed to grooves which remain open in the tire's footprint.

[0018] "Tread element" or "traction element" means a rib or block element defined by a shape having adjacent grooves.

[0019] "Tread Arc Width" means the arc length of the tread measured between the lateral edges of the tread.

[0020] "Zigzag belt reinforcement structure" means a belt structure formed from at least two layers of interwoven cords, with ribbons of parallel cords having 1 to 20 cords in each ribbon arranged in an alternating pattern extending typically between 5 degrees and 45 degrees, more preferably between 3 degrees and 11 degrees, and most preferably between 5 degrees and 11 degrees, between the lateral edges of the belt. The invention will now be described, by way of example only, with reference to the accompanying drawings in which: [Brief explanation of the drawings]

[0021] [Figure 1] 1 shows a cross-sectional view of half of a tire of the present invention. [Figure 2A] 2 is a close-up perspective view of the top of FIG. 1 showing the cut protection belt and belt package of the present invention. [Figure 2B] 1 shows a close-up view of a single fiber of a cut protection belt. [Figure 3A] 1 shows a tire drum in which a zigzag belt structure is formed from wrapping strips around each lateral end of the drum. [Figure 3B] 1 shows a cross section of a reinforced strip with parallel reinforcements. [Figure 4] 1 shows the zigzag belt structure in formation. [Figure 5] 1 shows a cross section of a single fiber of the present invention in the form of a rectangle sandwiched between two semicircles. [Figure 6] 1 shows an oval cross section of a single fiber of the present invention. [Figure 7] 1 shows a rectangular cross section with rounded corners of a single fiber of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0022] FIG. 1 shows a cross-sectional view of a first embodiment of a tire 10 of the present invention. The radial tire in this example is an aircraft tire and includes a pair of bead portions 23, each including a bead core 22 embedded therein, sidewall portions 24 extending substantially outward from each of the bead portions 23 in the radial direction of the tire, and a substantially cylindrical tread portion 36 extending between the radially outer ends of the sidewall portions 24. The tire 10 is further reinforced by a carcass 31 extending annularly from one bead portion 23 to the other bead portion 23. The carcass 31 is composed of at least two carcass plies 32, for example, six carcass plies 32 in the illustrated embodiment. Of these carcass plies 32, four inner plies are wrapped around the bead core 22 from the inside to the outside of the tire to form a turnup portion, and two outer plies extend downward to the bead core 22 along the outside of the turnup portion of the inner carcass ply 32. Each of these carcass plies 32 includes a number of nylon cords, such as nylon 6,6 cords, extending substantially perpendicular to the equatorial plane E of the tire (ie, extending radially of the tire).

[0023] The belt package 40 is disposed between the carcass 31 and the tread rubber 36 and is composed of one or more belt plies 50, 52, 54, preferably a radially innermost belt located near the carcass 31. Preferably, the one or more belt plies 50, 52, 54 are low-angle belts having a belt angle of 10 degrees or less, more preferably a belt angle of 5 degrees or less. The low-angle belts 50, 52, 54 may be formed from belt plies having parallel cords at the desired angle, i.e., belts with cut ends, or may be formed by spirally winding one or more strips of cord around a tire building drum to form a continuous belt without cut ends. 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.

[0024] The belt package further includes one or more zigzag belt structures 62, 64, 66 located radially outward of the low angle belts 50, 52, 54. As shown in Figures 3 and 4, each of the radially outer zigzag belt structures is formed by wrapping one or more parallel rubberized strips 43 of reinforcing cords 46 in a generally circumferential direction at an angle extending between the side or lateral edges 44 and 45 of the layers forming a zigzag path, with the strips 43 being circumferentially shifted by approximately the width of the strip so as to form no gaps between adjacent strips 43. As a result, the cords 46 of each strip 43 extend in a substantially zigzag manner in the circumferential direction, changing their bending direction at the turn-back points at both ends 44, 45, and are substantially uniformly embedded in the first inner zigzag belt structure 62 over the entire area of ​​the first inner zigzag belt structure. The cords 46 of the zigzag belt structure cross each other at a cord angle A of 5 to 40 degrees relative to the equatorial plane of the tire as the strip 43 reciprocates between the opposite ply ends 44 and 45 at least once every 360 degrees of the circumference as described above.

[0025] The strips of reinforcing cord 43 preferably have a width W, which ranges from 0.2 to 1.5 inches. It is believed that a strip width W of 1.0 inch or less is preferred to form a zigzag path for the inner and outer layers 41, 42 and facilitate bending.

[0026] The radially outermost zigzag belt structure 66 is preferably the narrowest belt, with its belt edges extending over the sides of the belt edges of zigzag belt structures 64 and 62. The main belt layer is preferably formed from a hybrid or combined nylon and aramid cord. More preferably, the main belt cord structure is 3000 d / 2 aramid and 1680 d / 1 nylon.

[0027] The tire further includes an optional auxiliary belt layer 70 (not shown) located radially outward of the main belt package 40. The auxiliary belt layer 70 is preferably a zigzag belt layer formed of nylon cords having a cord structure of 1890d / 4 or 1890d / 3. The angle of the auxiliary belt layer can range from 0 to 30 degrees. The auxiliary belt layer has a width less than the main belt layer 40, and the belt width is preferably in the range of 50% to 110% of the width of the widest layer of the main belt.

[0028] The cushion gum layer 80 is located radially outside the auxiliary belt layer 70. The cushion gum layer 60 is formed from a hard compound and preferably has an elastic modulus of 20 to 22 MPa.

[0029] The cut protection belt 100 is located radially outside the cushion gum layer 80 and is the radially outermost belt. The cut protection belt 100 is preferably formed from a monofilament cord, preferably nylon MXD6 or nylon 6 / 6, although it may also be a blend of nylon, nylon 6 / 6, or other organic materials. Preferably, the cut protection belt 100 is formed from one to four layers of monofilament cord, with the layers formed so as to have no cut edges. Thus, the cut protection belt is formed with one or more zigzag belt structures having two interwoven cord layers. The cut protection belt may also be formed with a spirally wound belt layer without cut edges. The cut protection belt may include two zigzag belts forming four layers, or up to four spirally wound layers. The cut protection belt may further include a zigzag belt structure combined with one or two spirally wound layers. The advantage of using a monofilament cord formed from nylon is that it is three times stronger and has a smaller gauge than conventional cords, allowing for up to four layers of cord without a significant weight penalty. Monofilament cords have a high lateral bending stiffness, making it difficult for the cord to bend out of the way of a nail or other penetrating foreign object.

[0030] The cut protection belt 100 preferably has a width extending from the first shoulder to the second shoulder, i.e., the entire width of the tread. As shown in Figures 3 and 4, the cut protection belt is preferably a zigzag belt formed by alternately winding single-fiber cords from one end of the belt or drum to the other end of the belt or drum. The angle of the single fibers in the zigzag belt may range from 1 to 45 degrees, more preferably from 3 to 30 degrees, and most preferably from 3 to 11 degrees. The cut protection belt may optionally include a low-angle belt (not shown) formed from single-fiber cords, which may be spirally wound to form a belt layer near zero degrees. The low-angle belt is preferably located radially inward of the cut protection belt 100 and preferably has a width covering the central one-third of the tread.

[0031] The monofilament nylon cord preferably has a non-circular, preferably flat, cross-sectional profile. One preferred cross-sectional profile is a rectangle sandwiched between two semicircles, as shown in FIG. 5. The sandwiched rectangle cross section has two semicircular sides 122, 124 connected by flat upper and lower parallel surfaces 126, 128. The sandwiched rectangle monofilament preferably has a width ranging from 0.02 to 2 inches, more preferably from 0.03 to 0.1 inches. The width-to-height ratio of the monofilament cord is preferably in the range of 2 to 10, more preferably 3 to 5. As shown in FIG. 6, a monofilament having an oval cross-sectional shape can be used, preferably with a width greater than its height. A monofilament having a rectangular cross-sectional shape can be used, as shown in FIG. 7, preferably with a width greater than its height, and preferably with rounded corners to avoid sharp edges. A larger width-to-height ratio increases lateral bending stiffness and enhances resistance to lateral thrust from penetrating objects. Thus, having a flat single fiber, such as a rectangle sandwiched between two semicircles or a rectangle, serves to capture a penetrating object more easily than a circular cross-sectional shape, which typically allows the penetrating object to pass by the single fiber to escape penetration. Other cross-sectional shapes of the single fiber can also be used, with wide and flat top and / or bottom surfaces being preferred. To improve adhesion of the rubber to the fiber, the single fiber is preferably coated with a suitable adhesive, such as an RFL, and further coated with a rubber coating, such as a belt or ply coat.

[0032] In one example of the invention, a nylon 6 / 6 monofilament cord with a 4400 / 1 dtex construction is used. The cord width or horizontal gauge is 1.13 mm and the vertical gauge is 0.38 mm. The cord LASE is 90 N at 7%, which is a cord extension of greater than 20% with a cord breaking load of 300 N. Cords are commercially available from Glassmaster and other manufacturers. In another example of the invention, a PET polyester monofilament cord with an 1100 / 9 dtex construction, a breaking strength of 650 N, and a gauge of 1.3 is used.

[0033] Variations of the present invention are possible in light of the description provided herein. While certain representative examples and details have been shown for the purpose of illustrating the present invention, it will be apparent to those skilled in the art that various changes and modifications can be made therein without departing from the scope of the invention. It is therefore to be understood that changes can be made in the particular examples described which are within the full scope of the invention, as defined by the following appended claims.

Claims

1. 1. A tire having a cut protection belt located radially outward of a main belt structure, the cut protection belt being a zigzag belt structure, the zigzag belt structure having a single-fiber cord wound in a zigzag pattern from a first lateral end to a second lateral end to form an integrally formed dual cord layer, the single-fiber cord having a non-circular cross-sectional shape; A cushion gum layer is further provided between the main belt structure and the cut protection belt, The tire according to claim 1, wherein the cut protection belt further comprises a spirally wound monofilament cord belt.

2. 2. The tire of claim 1, wherein the spirally wrapped belt is located radially inward of the zigzag belt structure.

3. 3. A tire according to claim 1 or 2, characterized in that the monofilament cords of the zigzag belt structure are angled in the range of 1 to 45 degrees.

4. A tire having a cut protection belt located radially outward of a main belt structure, the cut protection belt being a zigzag belt structure, the zigzag belt structure forming an integrally formed dual (two) cord layer by winding a single fiber cord in a zigzag pattern from a first lateral end to a second lateral end, the cross-sectional shape of the single fiber cord being non-circular, A cushion gum layer is further provided between the main belt structure and the cut protection belt, The tire is characterized in that the monofilament cords of the zigzag belt structure are angled in the range of 5 degrees to 11 degrees.

5. 5. A tire according to claim 1 or 4, characterized in that the monofilament cord has a cross-sectional shape with a flat surface.

6. The tire of claim 1 or 4, wherein said monofilament cord has a width ranging from 0.02 inches to 2 inches.

7. 5. A tire according to claim 1 or 4, characterized in that the monofilament cord has a width greater than its height.

8. The tire of claim 1 or 4, wherein said monofilament cord has a height in the range of 0.002 inches to 1.0 inches.

9. 5. Tire according to claim 1 or 4, characterized in that the width to height ratio of said monofilament cord is in the range of 2 to 10.

10. 5. The tire according to claim 1, wherein the monofilament cord has a cross-sectional shape of a rectangle sandwiched between two semicircles.

11. 5. A tire according to claim 1 or 4, characterized in that the monofilament cord has a rectangular cross-sectional shape with rounded corners.

12. 5. A tire according to claim 1 or 4, characterized in that the monofilament cord has an elliptical cross-sectional shape.

13. 5. A tire according to claim 1 or 4, characterized in that the monofilament cord has an oval cross-sectional shape.

14. 5. A tire according to claim 1 or 4, characterized in that the monofilament cord is nylon.

15. 5. A tire according to claim 1 or 4, characterized in that the monofilament cord is nylon 6 / 6.

16. A tire having a cut protection belt located radially outward of a main belt structure, the cut protection belt being a zigzag belt structure, the zigzag belt structure being formed with two integrally formed cord layers by wrapping a single-fiber cord in a zigzag pattern from a first lateral end to a second lateral end, the single-fiber cord having a cross-sectional shape with a flat upper surface; A cushion gum layer is further provided between the main belt structure and the cut protection belt, The tire according to claim 1, wherein the cut protection belt further comprises a spirally wound monofilament cord belt.

17. A tire having a cut protection belt located radially outward of a main belt structure, the cut protection belt being a zigzag belt structure, the zigzag belt structure being formed by wrapping a single fiber cord in a zigzag pattern from a first lateral end to a second lateral end to form two integrally formed cord layers, the cross-sectional shape of the single fiber cord having a flat upper surface, A cushion gum layer is further provided between the main belt structure and the cut protection belt, The tire is characterized in that the monofilament cords of the zigzag belt structure are angled in the range of 5 degrees to 11 degrees.

18. A tire according to claim 16 or 17, characterized in that the width to height ratio of said monofilament cord is in the range of 2 to 10.

19. A tire having a cut protection belt located radially outward of a main belt structure, the cut protection belt being formed by spirally winding a monofilament cord, the monofilament cord being made of nylon and having a non-circular cross-sectional shape, and further comprising a cushion gum layer between the main belt structure and the cut protection belt; The tire according to claim 1, wherein the cut protection belt further comprises a spirally wound monofilament cord belt.

20. A tire having a cut protection belt located radially outward of a main belt structure, said cut protection belt being formed by spirally winding a single fiber cord, said single fiber cord being formed of nylon and having a non-circular cross section, and further comprising a cushion gum layer between said main belt structure and said cut protection belt; The tire is characterized in that the monofilament cords of the zigzag belt structure are angled in the range of 5 degrees to 11 degrees.

21. Tire according to claim 19 or 20, characterized in that the width to height ratio of said monofilament cord is in the range of 2 to 10.

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