TYRE FOR TWO-WHEELED VEHICLE AND PROCESS FOR MANUFACTURING THE SAME
1 Assignment
0 Petitions
Accused Products
Abstract
In the manufacture of a tyre, a belt structure is made by means of strip-like segments or elements, each comprising parallel cords embedded in an elastomeric layer, sequentially laid along the circumferential extension of a toroidal support, in such a manner that: each strip-like element is laid in a laying trajectory defining, at each point, a laying angle; at each point of the laying trajectory a laying gap is formed between adjacent strip-like elements, the laying trajectory being formed starting from preselected laying angles on the shoulder and on the crown of the tyre, the laying gap between adjacent strip-like elements varying along at least one section of the laying trajectory between crown and shoulder so as to cause variation of the laying angle and to obtain the preselected angles on the shoulder and on the crown.
4 Citations
40 Claims
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1-20. -20. (canceled)
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21. A tyre for two-wheeled vehicles comprising:
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a carcass structure of substantially toroidal shape comprising a central crown portion and two axially opposite side portions, each side portion being associated with a respective bead structure; a belt structure of substantially annular shape applied at a radially external position to the carcass structure at the central crown portion; a tread band applied at a radially external position relative to the belt structure; and a pair of sidewalls, each sidewall covering a side portion of the tyre between a lateral edge of the tread band and the respective bead structure, said tyre having a transverse-curvature ratio f/C≧
0.2 and a height sidewall ratio (H−
f)/H≦
0.7;said belt structure comprising at least one belt layer formed with a plurality of strip-like elements, each comprising reinforcing thread elements disposed parallel to each other along a longitudinal direction of the strip-like element; and each reinforcing element being disposed in a laying trajectory defining, at each point, a laying angle relative to a meridian plane of the tyre passing through that point, wherein the strip-like elements of said plurality are laid in such a manner that a distance or gap between a last reinforcing element of a strip-like element and a first reinforcing element of a subsequent strip-like element in a circumferential direction is variable over at least one section of respective laying trajectories. - View Dependent Claims (22, 23, 24, 25, 26, 27, 28, 29, 30)
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31. A process for manufacturing a tyre for two-wheeled vehicles of the type provided with a transverse-curvature ratio f/C≧
- 0.2 and a height sidewall ratio (H−
f)/H≦
0.7, comprising;manufacturing a carcass structure of substantially toroidal shape, said carcass comprising a central crown portion and two axially opposite side portions; manufacturing a belt structure of substantially annular shape at a radially external position to the carcass structure, at the central crown portion, the manufacturing of the belt structure comprising manufacturing of at least one belt layer through laying on said carcass structure of a plurality of strip-like elements, comprising reinforcing thread elements disposed parallel to each other along a longitudinal direction of the strip-like element, the manufacturing of said at least one belt layer comprising; determining laying angles of the reinforcing elements at the shoulder α
sp and at the equatorial plane α
c that are to be obtained on the tyre;determining a laying trajectory of the strip-like elements defining, at each point, a laying angle (α
) relative to a meridian plane of the carcass structure passing through that point so as to obtain said angles α
sp, α
c, said laying trajectory being in relationship with a strip-like element laying distance or inter-gap between a last reinforcing element of a strip-like element and a first reinforcing element of a strip-like element subsequently laid in the circumferential direction,said distance varying in a controlled and predetermined manner over at least one section of respective laying trajectories of two strip-like elements subsequently laid in a circumferential direction; and laying each strip-like element according to the aforesaid laying trajectory. - View Dependent Claims (32, 33, 34, 35, 36, 37, 38, 39, 40)
wherein; Sc is a circumferential extension of the belt layer at the equatorial plane of the tyre; α
c is the laying angle of each strip-like element relative to said equatorial plane; andL is a transverse width of each strip-like element.
- 0.2 and a height sidewall ratio (H−
-
36. The process for manufacturing a tyre as claimed in claim 35, wherein:
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said laying trajectory is formed starting from preselected laying angles on the shoulder α
sp and at the equatorial plane α
c of the tyre; andthe strip-like element inter-gap between one strip-like element and the subsequently laid strip-like element varies over at least one section of respective laying trajectories of two subsequently laid strip-like elements in the circumferential direction between equatorial plane and shoulder, in order to cause variation of said laying angle (α
) and obtain said preselected angles on the shoulder and at the equatorial plane.
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37. The process for manufacturing a tyre as claimed in claim 36, wherein the laying trajectory and the strip-like element inter-gap at each laying point between one strip-like element and the subsequently laid strip-like element are a function of:
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an imposed maximum gap (Δ
gmax);a width of the strip-like element L; and said preselected angles on the shoulder α
sp and at the equatorial plane α
c.
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38. The process for manufacturing a tyre as claimed in claim 33, comprising:
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calculating a minimum rounded off by defect between a number (Nsp) of strip-like elements corresponding to the angle on the shoulder and a number (Nc) of strip-like elements corresponding to the angle at the equatorial plane min (integer|Nsp;
Nc|);calculating N1=min(integer|N sp;
Nc|)−
1;calculating the strip-like element inter-gap on the shoulder (Δ
sp) and at the equatorial plane (Δ
gc) for N1; andcomparing (Δ
sp) and (Δ
gc) with an imposed Δ
gmax;
if Δ
sp≦
Δ
gmax and Δ
gc Δ
gmax, setting N1=N,on the contrary, if Δ
sp≧
Δ
gmax or Δ
gc≧
Δ
gmax, calculating Nn as min (integer|Nsp;
Nc|)−
n, on varying of n, and recalculating corresponding strip-like element inter-gap on the shoulder Δ
sp and on the crown Δ
gc for each Nn;
setting N=Nn wherein Nn is an integer of strip-like elements satisfying a relation Δ
sp(Nn)≦
Δ
gmax and Δ
gc(Nn)≦
Δ
gmax.
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39. The process for manufacturing a tyre as claimed in claim 38, wherein Nc=(Sc/Lc)−
- senα
c and Nsp=(Ssp/Lsp)*senα
sp, are S the circumferential extension of the belt layer at angle α
.
- senα
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40. The process for manufacturing a tyre as claimed in claim 39, wherein Δ
-
sp=Ssp/Nn−
Lsp/senα
sp and Δ
gc=Sc/Nn−
Lc/senα
c.
-
sp=Ssp/Nn−
Specification