Spreading noise generated by load supporting elements

In a tire adapted to rotate around an axis, the tire being provided with a plurality of circumferentially extending tread design cycles defining a dimensional parameter varying in a predetermined manner, an improved tread arrangement 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 lengths corresponding to three different times of the group consisting of the first nine terms of the harmonic series, whereby the character of the sound emitted when the tire 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 dimensional parameter varying 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 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 tire rotates against a road surface is altered.

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 and arranged about said tread so as to provide a plurality of not less than three harmonic segments, the design cycle lengths in each of said harmonic segments having a different period, the rounded fractional portions of the circumference represented by the different periods 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 harmonic segment periods corresponding to a different frequency in the sound spectrum.

In a tire adapted to rotate around an axis, the tire being provided with a plurality of circumferentially extending tread design cycles defining a dimensional parameter varying in a predetermined manner, an improved tread arrangement in which:

• the design cycles are divided into a plurality of not less than three complete modulation cycles of different lengths, the relative difference between the largest and second largest of said three lengths being at least as great as the relative difference between the seventh and eighth terms of the harmonic series and the relative difference between the second largest and smallest of said three lengths being at least as great as the relative difference between the eighth and ninth terms of the harmonic series, the sum of said three lengths occupying at least one-half the circumference of the tire, said tire tread comprising one or more additional complete modulation cycles having one or more additional lengths shorter than any of said three lengths, the sum of any of the additional lengths which are substantially identical being less than the smallest of said three lengths.

A tread for a tire adapted to rotate around an axis, the tread comprising a plurality of circumferentially extending tread design cycles defining a dimensional parameter varying 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 relative difference between the largest and second largest of said three lengths being at least as great as the relative difference between the seventh and eighth terms of the harmonic series and the relative difference between the second largest and smallest of said three lengths being at least as great as the relative difference between the eighth and ninth terms of the harmonic series, the sum of said three lengths occupying at least one-half the circumference of the tread, said tread comprising one or more additional complete modulation cycles having one or more additional lengths shorter than any of said three lengths, the sum of any of the additional lengths which are substantially identical being less than the smallest of said three lengths.

In an apparatus provided with a plurality of surface-engaging design cycles located on a curved face of the apparatus, said design cycles defining a dimensional parameter varying in a predetermined manner, an improved arrangement in which:

• the design cycles are divided into a plurality of not less than three complete modulation cycles of different lengths, the relative difference between the largest and second largest of said three lengths being at least as great as the relative difference between the seventh and eighth terms of the harmonic series and the relative difference between the second largest and smallest of said three lengths being at least as great as the relative difference between the eighth and ninth terms of the harmonic series, the sum of said three lengths occupying at least one-half the curved face of the apparatus, said face comprising one or more additional complete modulation cycles having one or more additional lengths shorter than any of said three lengths, the sum of any of the additional lengths which are substantially identical being less than the smallest of said three lengths.

A method of manufacturing the tread of a tire adapted to rotate around an axis, the tread being provided with a plurality of circumferentially extending tread design cycles defining a dimensional parameter varying in a predetermined manner, said method comprising the steps of:

• dividing the design cycles into a plurality of not less than three complete modulation cycles of different lengths, and
• arranging the rounded fractional portions of the circumference represented by the different lengths to correspond 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.