Spreading noise generated by load supporting elements of a tire tread

A tire provided with a tread having a plurality of load supporting elements placed about the circumference of said tire, said tread comprising:

• a plurality of repeating design cycles placed continuously about the circumference of said tire, said design cycles having at least two different pitch lengths including a shortest pitch length and a longest pitch length arranged about said tread so as to provide a plurality of not less than three harmonic segments of different lengths, not more than one-half of the length of any of said three harmonic segments comprising consecutive pitches of the same length, the boundary between said harmonic segments being determined by a transition from a pitch length longer than said shortest pitch length to said shortest pitch length, the rounded fractional portions of the circumference represented by the lengths of the three harmonic segments corresponding to three different terms of the group consisting of the first nine terms of the harmonic series, each of said three harmonic segments corresponding to a different frequency in the sound spectrum and comprising:
• (1) a first harmonic segment having a first length varying by ten percent or less from a length corresponding to a first term of said three different terms;
• (2) a second harmonic segment having a second length varying by ten percent or less from a length corresponding to a second term of said three different terms and
• (3) a third harmonic segment having a third length varying by ten percent or less from a length corresponding to a third term of said three different terms.

A tire provided with a tread having a plurality of load supporting elements placed about the circumference of said tire, said tread comprising:

• a plurality of repeating design cycles placed continuously about the circumference of said tire, said design cycles having at least two different pitch lengths including a shortest pitch length and a longest pitch length arranged about said tread so as to provide a plurality of not less than three harmonic segments of different lengths, each of said three harmonic segments including at least one of each different pitch length used in the tire, the boundary between said harmonic segments being determined by a transition from a pitch length longer than said shortest pitch length to said shortest pitch length, the rounded fractional portions of the circumference represented by the lengths of the three harmonic segments corresponding to three different terms of the group consisting of the first nine terms of the harmonic series, each of said three harmonic segments corresponding to a different frequency in the sound spectrum, the total number of harmonic segments lying in the range equal to:
• [NP.times.(LP-SP)]/[B.times.(LP+SP)]
• wherein
• NP is the number of design cycles,
• LP is the longest pitch length,
• SP is the shortest pitch length, and
• B is the modulation index and includes the range of values from 1.6 to 2.9.

A tire provided with a tread having a plurality of load supporting elements placed about the circumference of said tire, said tread comprising:

• a plurality of repeating design cycles placed continuously about the circumference of said tire, said design cycles having at least two different pitch lengths including a shortest pitch length and a longest pitch length arranged about said tread so as to provide a plurality of not less than three harmonic segments of different lengths, the boundary between said harmonic segments being determined by a transition from a pitch length longer than said shortest pitch length to said shortest pitch length, the rounded fractional portions of the circumference represented by the lengths of the three harmonic segments corresponding to three different terms of the group consisting of the first nine terms of the harmonic series, each of said three harmonic segments corresponding to a different frequency in the sound spectrum and comprising:
• (1) a first harmonic segment having a first length varying by ten percent or less from a length corresponding to a first term of said three different terms;
• (2) a second harmonic segment having a second length varying by ten percent or less from a length corresponding to a second term of said three different terms;
• and
• (3) a third harmonic segment having a third length varying by ten percent or less from a length corresponding to a third term of said three different terms,
• the total number of harmonic segments in said tread lying in the range equal to:
• [NP.times.(LP-SP)]/[B.times.(LP+SP)]
• wherein
• NP is the number of design cycles,
• LP is the longest pitch length,
• SP is the shortest pitch length, and
• B is the modulation index and includes the range of values from 1.6 to 2.9.

A tire provided with a tread having a plurality of load supporting elements placed about the circumference of said tire, said tread comprising:

• a plurality of repeating design cycles placed continuously about the circumference of said tire, said design cycles having at least two different pitch lengths including a shortest pitch length and a longest pitch length arranged about said tread so as to provide a plurality of not less than three harmonic segments of different lengths, the boundary between said three harmonic segments being determined by a transition from a pitch length longer than said shortest pitch length to said shortest pitch length, the rounded fractional portions of the circumference represented by the lengths of the three harmonic segments corresponding to three different terms of the group consisting of the first nine terms of the harmonic series, each of said three harmonic segments corresponding to a different frequency in the sound spectrum, the total number of harmonic segments being at least as large as a number equal to the circumference of the tire measured in centimeters divided by 44.704 but not less than three, and lying in the range equal to:
• [NP.times.(LP-SP)]/[B.times.(LP+SP)]
• wherein
• NP is the number of design cycles,
• LP is the longest pitch length,
• SP is the shortest pitch length, and
• B is the modulation index and includes the range of values from 1.6 to 2.9.

A tread for a tire adapted to rotate around an axis, the tread comprising a plurality of circumferentially extending tread design cycles defining a plurality of different design cycle lengths varying from a shortest length to a longest length in a predetermined manner in which:

• the design cycles are divided into a plurality of not less than three complete modulation cycles of different lengths, not more than one-half of the length of any of said three modulation cycles comprising consecutive design cycles of the same length, the rounded fractional portions of the circumference represented by the different modulation cycle lengths corresponding to three different terms of the group consisting of the first nine terms of the harmonic series, said three complete modulation cycles, comprising:
• (1) a first modulation cycle having a first length varying by ten percent or less from a length corresponding to a first term of said three different terms;
• (2) a second modulation cycle having a second length varying by ten percent or less from a length corresponding to a second term of said three different terms;
• and
• (3) a third modulation cycle having a third length varying by ten percent or less from a length corresponding to a third term of said three different terms, whereby the character of the sound emitted when the tread rotates against a road surface is altered.

A tread for a tire adapted to rotate around an axis, the tread comprising a plurality of circumferentially extending tread design cycles defining a plurality of different design cycle lengths varying from a shortest length to a longest length in a predetermined manner in which:

• the design cycles are divided into a plurality of not less than three complete modulation cycles of different lengths, each of said three complete modulation cycles including at least one of each different design cycle length used in the tread, the rounded fractional portions of the tread circumference represented by the different modulation cycle lengths corresponding to three different terms of the group consisting of the first nine terms of the harmonic series, the total number of modulation cycles lying in the range equal to:
• [NP.times.(LP-SP)]/[B.times.(LP+SP)]
• wherein
• NP is the number of design cycles,
• LP is the longest design cycle length,
• SP is the shortest design cycle length, and
• B is the modulation index and lies in the range of values from 1.6 to 2.9,
• whereby the character of the sound emitted when the tread rotates against a road surface is altered.

A tread for a tire adapted to rotate around an axis, the tread comprising a plurality of circumferentially extending tread design cycles defining a plurality of different design cycle lengths varying from a shortest length to a longest length in a predetermined manner in which:

• the design cycles are divided into a plurality of not less than three complete modulation cycles of different lengths, the rounded fractional portions of the circumference represented by the different modulation cycle lengths corresponding to three different terms of the group consisting of the first nine terms of the harmonic series, said three complete modulation cycles, comprising:
• (1) a first modulation cycle having a first length varying by ten percent or less from a length corresponding to a first term of said three different terms;
• (2) a second modulation cycle having a second length varying by ten percent or less from a length corresponding to a second term of said three different terms;
• and
• (3) a third modulation cycle having a third length varying by ten percent or less from a length corresponding to a third term of said three different terms;
• the total number of modulation cycles lying in the range equal to:
• [NP.times.(LP-SP)]/[B.times.(LP+SP)]
• wherein
• NP is the number of design cycles,
• LP is the longest design cycle length,
• SP is the shortest design cycle length, and
• B is the modulation index and lies in the range of values from 1.6 to 2.9,
• whereby the character of the sound emitted when the tread rotates against a road surface is altered.

A tread for a tire adapted to rotate around an axis, the tread comprising a plurality of circumferentially extending tread design cycles defining a plurality of different design cycle lengths varying from a shortest length to a longest length in a predetermined manner in which:

• the design cycles are divided into a plurality of not less than three complete modulation cycles of different lengths, the rounded fractional portions of the circumference represented by the different modulation cycle lengths corresponding to three different terms of the group consisting of the first nine terms of the harmonic series, whereby the character of the sound emitted when the tread rotates against a road surface is altered, the total number of complete modulation cycles being at least as large as a number equal to the circumference of the tire measured in centimeters divided by 44.704, but not less than three, and lying in the range equal to:
• [NP.times.(LP-SP)]/[B.times.(LP+SP)]
• wherein
• NP is the number of design cycles,
• LP is the longest design cycle length,
• SP is the shortest design cycle length, and
• B is the modulation index and lies in the range of values from 1.6 to 2.9.