JP2021146907A - Tire, tire manufacturing method, tire design method, and method for determining arrangement of pattern constitution unit - Google Patents

Abstract

To provide a tire capable of reducing pitch noise according to tread patterns, a tire manufacturing method, a tire design method, and a method for determining an arrangement of pattern constitution units.SOLUTION: Both the sum total Nt of first pattern constitution units 4A in a tire circumference and the sum total of second pattern constitution units 4B in a tire circumference have the greatest common divisor GCD other than 1. The first pattern constitution units 4A are replaced with first pulses having a size B according to a length D1 in the tire circumferential direction of the first pattern constitution units 4A, and first pattern rows 5A are replaced with first pulse trains which are arranged side by side with intervals G according to the length D1 in the tire circumferential direction of the pattern constitution units 4A. When second pulse trains made to be the N/GCD number of second pulses by adding the Nt/GCD number of the adjacent first pulses in the first pulse trains 11 are acquired, the maximum value Fmax of the 1-order to k-order amplitudes Fk obtained after Fourier transformation of the second pulse trains satisfies certain conditions.SELECTED DRAWING: Figure 1

Description

The present invention relates to a tire having a tread portion, a method for manufacturing the tire, a method for designing the tire, and a method for determining the arrangement of pattern constituent units.

Conventionally, a tire having a tread pattern including rows in which at least two types of pattern constituent units are arranged in the tire circumferential direction is known in the tread portion. For example, in Patent Document 1 below, the sequence of pattern constituent units is replaced with a pulse train in which the pattern constituent unit is a pulse, and the maximum value F _{max of the amplitude F k} of the 1st to kth order obtained by Fourier transforming the pulse train is defined. We are proposing tires with reduced pitch noise limited to the range of.

Japanese Unexamined Patent Publication No. 2019-09913

However, the tire of Patent Document 1 does not consider a tread pattern in which the length in the tire circumferential direction differs for each row of pattern constituent units, and it has been desired to reduce pitch noise according to the tread pattern.

The present invention has been devised in view of the above circumstances, and provides a tire capable of reducing pitch noise according to a tread pattern, a tire manufacturing method, a tire design method, and a method for determining an arrangement of pattern constituent units. The main purpose is to do.

ここで、
Ｌ：タイヤ周長変数（タイヤ１周の全ての第１模様構成単位の長さの比の総和）
ｋ：１〜２Ｎまでの自然数
Ｘ（ｊ）：第２パルス列の起点からｊ番目のパルス位置（起点からｊ番目までの第２パルスの間隔の和）
Ｐ（ｊ）：第２パルス列のｊ番目の第２パルスの大きさ
ｍ：第１模様構成単位の種類数 The present invention is a tire having a tread portion, and the tread portion includes a first pattern array in which at least two types of first pattern constituent units having different lengths in the tire circumferential direction are arranged in the tire circumferential direction. A tread pattern including a second pattern row in which a plurality of second pattern constituent units are arranged in the tire circumference direction is provided, and the total number Nt of the first pattern constituent units in one tire lap and the first pattern in one tire lap. The total number N of the two pattern constituent units has a greatest common divisor GCD other than 1, and the first pattern constituent unit has a size corresponding to the length of the first pattern constituent unit in the tire circumferential direction. Substituted with one pulse, the first pattern train is arranged in the order of the arrangement of the first pattern constituent units with the first pulse at intervals according to the length of the first pattern constituent units in the tire circumferential direction. 2) The greatest value F _{max of the amplitude F k} of the 1st to kth order obtained by Fourier transforming the pulse train by the following equation (1) satisfies the following equation (2).

here,
L: Tire circumference variable (sum of the ratio of the lengths of all the first pattern constituent units in one tire circumference)
k: Natural number from 1 to 2N X (j): Jth pulse position from the starting point of the second pulse train (sum of intervals of the second pulse from the starting point to the jth pulse)
P (j): Magnitude of the jth second pulse of the second pulse train m: Number of types of the first pattern constituent unit

In the tire of the present invention, it is desirable that the second pulse train is one second pulse by adding two adjacent pulses of the first pulse train.

In the tire of the present invention, the magnitude of the first pulse is the tire circumference of at least two types of the first pattern constituent units, which is the length in the tire circumferential direction of the first pattern constituent unit corresponding to the first pulse. It should be defined as the ratio of the length of the direction to the median.

In the tire of the present invention, the ratio is preferably 0.05 to 0.35.

In the tire of the present invention, it is desirable that the first-order amplitude F _{1 of the first-order amplitude F k} is 2.0 or less.

In the tire of the present invention, it is desirable that the amplitude F1 of the _{first order is 1.0 or less among the amplitudes Fk of the 1st to kth orders.}

In the tire of the present invention, the out of 1~k following amplitude _{F k,} 2/3 or more amplitude _{F k} of the maximum value _{F max} is not continuously adjacent order is desirable.

In the tire of the present invention, it is desirable that the total number Nt of the first pattern constituent units in one round of the tire is 30 to 90.

ここで、
Ｌ：タイヤ周長変数（タイヤ１周の全ての第１模様構成単位の長さの比の総和）
ｋ：１〜２Ｎまでの自然数
Ｘ（ｊ）：第２パルス列の起点からｊ番目のパルス位置（起点からｊ番目までの第２パルスの間隔の和）
Ｐ（ｊ）：第２パルス列のｊ番目の第２パルスの大きさ
ｍ：第１模様構成単位の種類数 In the present invention, at least two types of first pattern constituent units having different lengths in the tire circumferential direction are arranged in the tire circumferential direction in the tread portion, and a plurality of second pattern constituent units are arranged in the tire circumferential direction. A method for manufacturing a tire provided with a tread pattern including a second pattern train arranged in the above, wherein the total number Nt of the first pattern constituent units in one lap of the tire and the first lap in the tire. When the total number N of the two pattern constituent units has a maximum commitment number GCD other than 1, the first pattern constituent unit has a size corresponding to the length of the first pattern constituent unit in the tire circumferential direction. The first step of replacing the first pulse with the first pattern train and the first pattern train are arranged in the order of the first pulse of the first pattern constituent unit according to the length of the first pattern constituent unit in the tire circumferential direction. The second step of replacing the tires with the first pulse trains arranged at intervals and the second pulse train of N / GCD tires obtained by adding the adjacent Nt / GCD tires of the first tire trains to form the second pulse trains of N / GCD tires. a third step of obtaining, the maximum value F _max of 1~k following amplitude F _k obtained a second pulse train by Fourier transform by the following equation (1) is the satisfying the following formula (2) the It is characterized by including a fourth step of forming one pattern train.

here,
L: Tire circumference variable (sum of the ratio of the lengths of all the first pattern constituent units in one tire circumference)
k: Natural number from 1 to 2N X (j): Jth pulse position from the starting point of the second pulse train (sum of intervals of the second pulse from the starting point to the jth pulse)
P (j): Magnitude of the jth second pulse of the second pulse train m: Number of types of the first pattern constituent unit

ここで、
Ｌ：タイヤ周長変数（タイヤ１周の全ての第１模様構成単位の長さの比の総和）
ｋ：１〜２Ｎまでの自然数
Ｘ（ｊ）：第２パルス列の起点からｊ番目のパルス位置（起点からｊ番目までの第２パルスの間隔の和）
Ｐ（ｊ）：第２パルス列のｊ番目の第２パルスの大きさ
ｍ：第１模様構成単位の種類数 In the present invention, in the tread portion, at least two types of first pattern constituent units having different lengths in the tire circumferential direction are arranged in the tire circumferential direction, and a plurality of second pattern constituent units are arranged in the tire circumferential direction. This is a method for designing a tire provided with a tread pattern including a second pattern train arranged in the above, wherein the total number Nt of the first pattern constituent units in one lap of the tire and the first lap in the tire. When the total number N of the two pattern constituent units has the greatest common divisor GCD other than 1, the first pattern constituent unit has a size corresponding to the length of the first pattern constituent unit in the tire circumferential direction. The first step of substituting the first pulse and the first pattern sequence correspond to the length of the first pattern structural unit in the tire circumferential direction in the order of the arrangement of the first pulse of the first pattern structural unit. The second step of replacing with the first pulse train arranged at intervals and the second pulse train of N / GCD second pulses by adding the adjacent Nt / GCD first pulses of the first pulse train. a third step of obtaining, the said second pulse train so that the maximum value F _max of 1~k following amplitude F _k which is obtained by Fourier transform by the following equation (1) satisfies the following formula (2) the It is characterized by including a fourth step of determining the arrangement of one pattern constituent unit.

here,
L: Tire circumference variable (sum of the ratio of the lengths of all the first pattern constituent units in one tire circumference)
k: Natural number from 1 to 2N X (j): Jth pulse position from the starting point of the second pulse train (sum of intervals of the second pulse from the starting point to the jth pulse)
P (j): Magnitude of the jth second pulse of the second pulse train m: Number of types of the first pattern constituent unit

ここで、
Ｌ：タイヤ周長変数（タイヤ１周の全ての第１模様構成単位の長さの比の総和）
ｋ：１〜２Ｎまでの自然数
Ｘ（ｊ）：第２パルス列の起点からｊ番目のパルス位置（起点からｊ番目までの第２パルスの間隔の和）
Ｐ（ｊ）：第２パルス列のｊ番目の第２パルスの大きさ
ｍ：第１模様構成単位の種類数 The present invention is a method for determining the arrangement of the pattern constituent units constituting the pattern sequence in the tire circumferential direction with respect to the pattern sequence included in the tread pattern of the tire, and the pattern sequence is the length in the tire circumferential direction. A tire includes a first pattern sequence in which at least two types of first pattern constituent units having different characteristics are arranged in the tire circumferential direction, and a second pattern sequence in which a plurality of second pattern constituent units are arranged in the tire circumferential direction. When the total number Nt of the first pattern constituent units in one lap and the total number N of the second pattern constituent units in one lap of the tire have a maximum commitment number GCD other than 1, the first pattern constituent unit is used. , The first step of replacing the first pattern constituent unit with a first pulse having a size corresponding to the length in the tire circumferential direction, the first pattern train, and the first pulse being the first pattern constituent unit. The second step of replacing the first pattern structural unit with a first pulse train arranged at intervals according to the length in the tire circumferential direction, and the adjacent Nt / GCD of the first pulse train. The third step of acquiring a second pulse train obtained by adding the first pulses to form N / GCD second pulses, and the 1st to kth orders obtained by Fourier transforming the second pulse train with the following equation (1). It is characterized by including a fourth step of determining the arrangement of the first pattern structural unit so that the maximum value F _max of the amplitude F _{k of the above satisfies the following equation (2).}

here,
L: Tire circumference variable (sum of the ratio of the lengths of all the first pattern constituent units in one tire circumference)
k: Natural number from 1 to 2N X (j): Jth pulse position from the starting point of the second pulse train (sum of intervals of the second pulse from the starting point to the jth pulse)
P (j): Magnitude of the jth second pulse of the second pulse train m: Number of types of the first pattern constituent unit

In the tire of the present invention, when the second pulse train obtained by adding the first pulses of Nt / GCD adjacent to the first pulse train to form the second pulse of N / GCD is obtained, the second pulse train is Fourier transformed. The maximum value F _max of the amplitude F _k of the 1st to kth order thus obtained satisfies a certain condition. For such a tire, the maximum value F _{max of the amplitude F k} is defined in consideration of the case where the length in the tire circumferential direction of the second pattern constituent unit is different from the length in the tire circumferential direction of the first pattern constituent unit. , Pitch noise can be further reduced.

The method for manufacturing a tire of the present invention includes a third step of adding the first pulses of Nt / GCD adjacent to the first pulse train to obtain a second pulse train of N / GCD second pulses, and the first step. It includes a fourth step of forming a pattern sequence in which the maximum value F _{max of the first- kth-} order amplitude F k obtained by Fourier transforming the two-pulse train satisfies a certain condition. In such a tire manufacturing method, the maximum value F _{max of the amplitude F k} is defined in consideration of the case where the length of the second pattern constituent unit in the tire circumferential direction is different from the length of the first pattern constituent unit in the tire circumferential direction. Therefore, it is possible to manufacture a tire with further reduced pitch noise.

The tire design method of the present invention includes a third step of adding the first pulses of Nt / GCD adjacent to the first pulse train to obtain a second pulse train of N / GCD second pulses, and the first step. It includes a fourth step of determining the arrangement of the pattern constituent units so that the maximum value F _{max of the first- kth-} order amplitude F k obtained by Fourier transforming the two-pulse train satisfies a certain condition. Such a tire design method defines a maximum value F _max of _{the amplitude F k in} consideration of the case where the length of the second pattern constituent unit in the tire circumferential direction is different from the length of the first pattern constituent unit in the tire circumferential direction. Therefore, it is possible to design a tire with further reduced pitch noise.

The method for determining the arrangement of the pattern constituent units of the present invention includes a third step of adding the first pulses of Nt / GCD adjacent to the first pulse train to obtain a second pulse train of N / GCD second pulses. The fourth step is to determine the arrangement of the pattern constituent units so that the maximum value F _{max of the first- kth-} order amplitude F k obtained by Fourier transforming the second pulse train satisfies a certain condition. In such a method of determining the arrangement of the pattern constituent units, the maximum value F _{max of the amplitude F k in} consideration of the case where the length of the second pattern constituent unit in the tire circumferential direction is different from the length of the first pattern constituent unit in the tire circumferential direction is taken into consideration. Therefore, it is possible to determine the arrangement of the tire pattern structural units with further reduced pitch noise.

It is a development view which shows an example of the tread part of a tire. It is a diagram which shows an example of the 1st pulse train. It is a diagram which shows an example of the 2nd pulse. It is a diagram which shows an example of the 2nd pulse train. It is a graph which shows the relationship between the amplitude F _{k and the degree k.} It is a flowchart of the arrangement determination method of a pattern composition unit.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. It should be noted that each drawing is for facilitating the understanding of the content of the invention, may include exaggerated display, and the scales and the like do not exactly match between the drawings.

FIG. 1 is a development view showing an example of the tread portion 2 of the tire 1 of the present embodiment. As shown in FIG. 1, a tread pattern 3 is provided on the tread portion 2 of the tire 1 of the present embodiment.

The tread pattern 3 of the present embodiment is configured to include a pattern row 5 in which a plurality of pattern building blocks 4 are arranged in the tire circumferential direction. The pattern rows 5 are provided at least in two rows, and in the present embodiment, five rows are provided. In the pattern row 5 of the present embodiment, a pair of first pattern rows 5A in which a plurality of first pattern constituent units 4A are arranged in the tire circumferential direction and a plurality of second pattern constituent units 4B are arranged in the tire circumferential direction. It includes a pair of second pattern rows 5B.

The pattern row 5 of the present embodiment further includes one third pattern row 5C in which a plurality of third pattern building blocks 4C are arranged in the tire circumferential direction. That is, the pattern constituent unit 4 of the present embodiment includes the first pattern constituent unit 4A arranged in the first pattern row 5A, the second pattern constituent unit 4B arranged in the second pattern row 5B, and the third pattern row. It includes a third pattern building block 4C arranged in 5C.

The first pattern row 5A of the present embodiment includes at least two types of first pattern constituent units 4A having different lengths D1 in the tire circumferential direction. The type of the length D1 of the first pattern constituent unit 4A can be appropriately set according to, for example, the conditions of the vehicle on which the tire 1 is mounted and the road surface. It is desirable that at least two types of first pattern constituent units 4A are randomly arranged. Such a first pattern sequence 5A can be expected to have a noise reduction effect due to so-called pitch variation, in which pitch noise is dispersed over a wide frequency range to form white noise.

Here, unless otherwise specified in the present specification, the dimensions and the like of each part of the tire 1 are values measured in a normal state. The "normal state" is a state in which, when the tire 1 is a pneumatic tire, the tire 1 is rim-assembled on a normal rim and adjusted to a normal internal pressure without load.

A "regular rim" is a rim defined for each tire in the standard system including the standard on which the tire 1 is based. For example, "standard rim" for JATTA, "Design Rim" for TRA, and ETRTO. If so, it is "Measuring Rim".

"Regular internal pressure" is the air pressure defined for each tire in the standard system including the standard on which Tire 1 is based. For JATMA, "maximum air pressure", for TRA, the table "TIRE LOAD LIMITS" The maximum value described in "AT VARIOUS COLD INFLATION PRESSURES", or "INFLATION PRESSURE" for ETRTO.

The length D1 of the first pattern constituent unit 4A in the tire circumferential direction is, for example, when the ratio D1 / Dc of at least two types of the first pattern constituent unit 4A of the length D1 in the tire circumferential direction to the median Dc is compared. Preferably, the absolute value of the difference in ratio D1 / Dc is 0.05 to 0.35. Here, the median value Dc when the first pattern constituent unit 4A has five kinds of lengths (D1 _LL , D1 _L , D1 _M , D1 _S , D1 _SS ) corresponds to the _{central length D1 M.}

When the absolute value of the difference is 0.05 or more, the noise reduction effect of the pitch variation can be effectively exhibited. From this point of view, the absolute value of the difference is preferably 0.10 or more, more preferably 0.15 or more.

When the absolute value of the difference is 0.35 or less, it is possible to suppress an increase in the rigidity difference between the pattern constituent units 4, and it is possible to suppress uneven wear of the tread portion 2. From this point of view, the absolute value of the difference is preferably 0.30 or less, more preferably 0.25 or less.

In the first pattern row 5A, the total number Nt of the first pattern constituent units 4A in one round of the tire can be appropriately set. The total number Nt of the first pattern constituent units 4A in one round of the tire is preferably 30 to 90.

When the total number of Nts is 30 or more, the noise reduction effect due to the pitch variation can be sufficiently exhibited. From such a viewpoint, the total number Nt is preferably 40 or more, and more preferably 50 or more.

When the total number of Nts is 90 or less, uneven wear of the tread portion 2 can be suppressed. From such a viewpoint, the total number Nt is preferably 80 or less, and more preferably 70 or less.

The first pattern constituent unit 4A is composed of, for example, one block 6 and one lateral groove 7 adjacent to the block 6 on one side in the tire circumferential direction. The first pattern sequence 5A of the present embodiment is a block pattern. It is desirable that the block 6 is divided into a lateral groove 7 and a main groove 8 extending in a direction intersecting the lateral groove 7 and continuously extending in the tire circumferential direction. The first pattern row 5A is not limited to the block pattern, and may be, for example, a rib pattern.

The second pattern row 5B of the present embodiment includes at least two types of second pattern building blocks 4B having different lengths D2 in the tire circumferential direction. The types of the second pattern constituent units 4B having different lengths D2 can be appropriately set according to, for example, the conditions of the vehicle on which the tire 1 is mounted and the road surface. It is desirable that at least two types of second pattern building blocks 4B are randomly arranged. Such a second pattern train 5B can be expected to have a noise reduction effect due to so-called pitch variation, in which pitch noise is dispersed over a wide frequency range to form white noise.

In the second pattern row 5B, the total number N of the second pattern constituent units 4B in one round of the tire can be appropriately set. The total number N of the second pattern constituent units 4B in one lap of the tire of the present embodiment is smaller than the total number Nt of the first pattern constituent units 4A in one lap of the tire. It is desirable that the total number Nt of the first pattern constituent units 4A in one lap of the tire and the total number N of the second pattern constituent units 4B in one lap of the tire have a greatest common divisor GCD other than 1.

The length D2 of the second pattern constituent unit 4B in the tire circumferential direction in the tread pattern 3 is Nt / N times the length D1 of the first pattern constituent unit 4A in the tire circumferential direction, which is twice in the present embodiment. Such a tire 1 can form an optimum pattern constituent unit 4 according to the position in the tire axial direction of the pattern row 5.

The second pattern structural unit 4B is composed of, for example, one rib 9 and at least one lateral groove 7 whose at least one end is terminated in the rib 9. The second pattern row 5B of the present embodiment is a rib pattern. The second pattern row 5B is not limited to the rib pattern, and may be, for example, a block pattern.

The third pattern row 5C of the present embodiment includes at least two types of third pattern constituent units 4C having the same pitch as the length D1 of the first pattern constituent unit 4A in the tire circumferential direction. Such a third pattern sequence 5C, together with the first pattern sequence 5A, can be expected to have a noise reduction effect due to so-called pitch variation, in which pitch noise is dispersed over a wide frequency range to form white noise.

The third pattern structural unit 4C is composed of, for example, one rib 9 and at least one lateral groove 7 whose at least one end is terminated in the rib 9. The third pattern row 5C of the present embodiment is a rib pattern. The third pattern row 5C is not limited to the rib pattern, and may be, for example, a block pattern.

FIG. 2 is a diagram showing an example of the first pulse train 11 for _{obtaining the amplitude F k.} In FIG. 2, the horizontal axis represents the interval G of the first pulse 10, and the vertical axis represents the magnitude B of the first pulse 10. As shown in FIGS. 1 and 2, the tire 1 has, for example, a first pulse having a first pattern constituent unit 4A and a size B corresponding to a length D1 of the first pattern constituent unit 4A in the tire circumferential direction. By substituting with 10 and arranging them, the pitch noise can be grasped.

The magnitude B of the first pulse 10 is the length of at least two types of the first pattern constituent unit 4A in the tire circumferential direction of the length D1 of the first pattern constituent unit 4A corresponding to the first pulse 10 in the tire circumferential direction. It is desirable to define it as the ratio D1 / Dc of D1 to the median Dc.

The magnitude B of at least two types of first pulses 10 defined as the ratio D1 / Dc preferably has an absolute difference of 0.05 to 0.35.

When the absolute value of the difference is 0.05 or more, the noise reduction effect of the pitch variation can be effectively exhibited. From this point of view, the absolute value of the difference is preferably 0.10 or more, more preferably 0.15 or more.

When the absolute value of the difference is 0.35 or less, it is possible to suppress an increase in the rigidity difference between the pattern constituent units 4, and it is possible to suppress uneven wear of the tread portion 2. From this point of view, the absolute value of the difference is preferably 0.30 or less, more preferably 0.25 or less.

The first pulse train 11 of the present embodiment corresponds to the first pattern train 5A and the first pulse 10 in the order of the arrangement of the first pattern building unit 4A according to the length D1 of the first pattern building unit 4A in the tire circumferential direction. They are arranged with an interval G. In the first pulse train 11, it is desirable that the first pulse 10 for one round of the first pattern train 5A is arranged. Therefore, the total number of the first pulses 10 is the total number Nt of the first pattern constituent units 4A in one round of the tire. The first pulse train 11 may be replaced with, for example, the third pattern train 5C.

The interval G of the first pulse 10 is the tire circumferential length D1 of the first pattern constituent unit 4A corresponding to the first pulse 10 in the tire circumferential direction of at least two types of the first pattern constituent units 4A. It is desirable to be defined as the ratio D1 / Dc to the median Dc of.

The interval G of the first pulse 10 corresponds to the length D1 in the tire circumferential direction of the first pattern configuration unit 4A corresponding to one of the first pulses 10 of the pair of first pulses 10 constituting the interval G. It is desirable to be defined. The interval G of the first pulse 10 is defined, for example, according to the average value of the lengths D1 of the two first pattern constituent units 4A corresponding to the pair of first pulses 10 constituting the interval G in the tire circumferential direction. May be good.

The interval G of at least two kinds of first pulses 10 defined as the ratio D1 / Dc preferably has an absolute value of the difference of 0.05 to 0.35.

When the absolute value of the difference is 0.05 or more, the noise reduction effect of the pitch variation can be effectively exhibited. From this point of view, the absolute value of the difference is preferably 0.10 or more, more preferably 0.15 or more.

When the absolute value of the difference is 0.35 or less, it is possible to suppress an increase in the rigidity difference between the pattern constituent units 4, and it is possible to suppress uneven wear of the tread portion 2. From this point of view, the absolute value of the difference is preferably 0.30 or less, more preferably 0.25 or less.

FIG. 3 is a _{diagram showing an example of the second pulse 12 for obtaining} the amplitude F k, and FIG. 4 is a diagram showing an example of the second pulse train 13. In FIGS. 3 and 4, the horizontal axis and the vertical axis are the same as those in FIG. As shown in FIGS. 2 to 4, the tire 1 of the present embodiment has acquired the first pulse train 11 to the second pulse train 13.

The second pulse train 13 is, for example, obtained by adding the adjacent Nt / GCD first pulses 10 of the first pulse train 11 to form the N / GCD second pulse 12. The second pulse train 13 of the present embodiment is exemplified by adding two adjacent first pulses 10 of the first pulse train 11 to form one second pulse 12. Such a second pulse train 13 can grasp the pitch noise of the first pattern train 5A in consideration of the influence of the second pattern train 5B.

The magnitude of the second pulse 12 is, for example, the sum of the magnitudes of the first pulses 10 to be added. It is desirable that the magnitude of the second pulse 12 is the sum of the magnitudes of the first pulses 10 of the Nt / GCD to be added dispersed in the N / GCD.

The interval of the second pulse 12 can be appropriately determined according to, for example, the length D2 of the second pattern building unit 4B in the tire circumferential direction. Therefore, the total number of the second pulses 12 of the present embodiment is the same as the total number N of the second pattern constituent units 4B in one round of the tire. The position of the second pulse 12 when the second pulse 12 is the sum of the two first pulses 10 may be, for example, an intermediate position of the first pulse 10 to be added.

ここで、
Ｌ：タイヤ周長変数（タイヤ１周の全ての第１模様構成単位４Ａの長さＤ１の比Ｄ１／Ｄｃの総和）
ｋ：１〜２Ｎまでの自然数
Ｘ（ｊ）：第２パルス列１３の起点からｊ番目のパルス位置（起点からｊ番目までの第２パルス１２の間隔の和）
Ｐ（ｊ）：第２パルス列１３のｊ番目の第２パルス１２の大きさ
ｍ：第１模様構成単位４Ａの種類数 As shown in FIG. 4, the tire 1 of the present embodiment has the maximum value of the _{amplitude F k} among the amplitudes F _{k of the 1st to kth} orders obtained by Fourier transforming the second pulse train 13 by the following equation (1). F _max is configured to satisfy the following equation (2).

here,
L: Tire circumference variable (sum of the ratio D1 / Dc of the length D1 of all the first pattern constituent units 4A of one tire circumference)
k: Natural number from 1 to 2N X (j): Jth pulse position from the starting point of the second pulse train 13 (sum of intervals of the second pulse 12 from the starting point to the jth)
P (j): Magnitude of the j-th second pulse 12 of the second pulse train 13 m: Number of types of the first pattern constituent unit 4A

The tire circumference variable L of the above formula (1) is a ratio D1 / Dc to the median Dc of the length D1 for all the first pattern constituent units 4A arranged over one tire circumference shown in FIG. It is defined as the sum.

The pulse positions X (j) (j is a natural number from 1 to N) in the above equation (1) are defined by the positions from an arbitrary starting point s of the second pulse train 13 to the jth second pulse 12. That is, the pulse position X (j) is defined as the sum of the intervals PL (j) of the second pulse 12 from the starting point s to the jth of the second pulse train 13 as follows.
X (1) = PL (1)
X (2) = PL (1) + PL (2)
・
・
・
X (j) = PL (1) + PL (2) + ... + PL (j)

As the starting point s, an arbitrary position of the second pulse train 13 can be selected, and for example, a position overlapping the second pulse 12 may be selected. The first second pulse 12 when the starting point s overlaps with the second pulse 12 is the second pulse 12 following the overlapped second pulse 12. Further, the interval PL (1) from the starting point s to the first second pulse 12 when the starting point s does not overlap with the second pulse 12 corresponds to the length from the starting point s to the first second pulse 12. ..

The magnitude P (j) of the second pulse 12 of the above equation (1) is defined as the magnitude of the j-th second pulse 12 from the starting point s of the second pulse train 13. The magnitude P (j) of the second pulse 12 of the present embodiment is defined as the sum of the magnitudes of the first pulses 10 of the Nt / GCDs to be added dispersed in the N / GCDs.

FIG. 5 is a graph showing the relationship between _{the amplitude F k and the order k.} In FIG. 5, the horizontal axis represents the order k and the vertical axis represents the amplitude F _k . As shown in FIG. 5, the amplitude F _k of the present embodiment is correlated with the magnitude of the noise energy when the frequency analysis of the pitch noise of the tire 1 during running.

In the tire 1 of the present embodiment, the maximum value F _{max of the amplitude F k} is defined according to the number m of the types of the first pattern constituent unit 4A and the total number Nt of the first pattern constituent unit 4A in one lap. There is. That is, the maximum value F _{max of the amplitude F k} when there are two types of the first pattern constituent units 4A is less than 13.5-0.105 Nt. Further, the maximum value F _{max of the amplitude F k} when the first pattern constituent unit 4A is three types is less than 10.5-0.055 Nt. Further, the maximum value F _{max of the amplitude F k} when there are five types of the first pattern constituent units 4A is less than 10.5-0.065 Nt.

In such a tire 1, the maximum value F _{max of the amplitude F k in} consideration of the tread pattern 3 is defined according to the number m of the types of the first pattern constituent unit 4A and the total number Nt, so that the pitch noise is further reduced. can do. Therefore, in the tire 1 of the present embodiment, in the tread pattern 3, the length D2 of the second pattern constituent unit 4B in the tire circumferential direction is different from the length D1 of the first pattern constituent unit 4A in the tire circumferential direction. Even if there is, the pitch noise can be further reduced.

Of 1~k following amplitude F _k, the amplitude F ₁ of the primary number is affected by noise energy which varies once in one cycle tires. Such a first-order amplitude F ₁ can be a factor that causes, for example, a roaring sound during traveling and a vibration inside the vehicle during traveling.

Of 1~k following amplitude _{F k,} the amplitude _{F 1} of the primary number is preferably 2.0 or less, more preferably 1.0 or less. Such a tire 1 can suppress the roaring noise during traveling, and can effectively suppress the vibration inside the vehicle during traveling.

Of 1~k following amplitude _{F k,} 2/3 or more amplitude _{F k} of the maximum value _{F max} is not continuously adjacent degree k is desirable. Such a tire 1 can prevent adjacent loud sounds of high frequencies from interfering with each other, and can further suppress a roaring sound during traveling.

Next, a method for determining the arrangement of the pattern constituent unit 4 of the present embodiment will be described with reference to FIGS. 1 to 5.
FIG. 6 is a flowchart of a method for determining the arrangement of the pattern constituent unit 4 of the present embodiment. As shown in FIG. 6, the method for determining the arrangement of the pattern constituent unit 4 of the present embodiment is for the pattern row 5 included in the tread pattern 3 of the tire 1 in the tire circumferential direction of the pattern constituent unit 4 constituting the pattern row 5. This is a method for determining the sequence of tires.

The pattern row 5 of the present embodiment includes a first pattern row 5A in which at least two types of first pattern constituent units 4A having different lengths D1 in the tire circumferential direction are arranged in the tire circumferential direction, and a plurality of second pattern constituent units. 4B includes a second pattern row 5B arranged in the tire circumferential direction. In the present embodiment, the total number Nt of the first pattern constituent units 4A in one lap of the tire and the total number N of the second pattern constituent units 4B in one lap of the tire have the greatest common divisor GCD other than 1. The method for determining the arrangement of the pattern constituent unit 4 of the present embodiment targets the tread pattern 3 including such a pattern sequence 5.

In the method for determining the arrangement of the pattern constituent unit 4 of the present embodiment, first, the first pattern constituent unit 4A has a first pulse 10 having a size B corresponding to the length D1 of the first pattern constituent unit 4A in the tire circumferential direction. The first step S1 is performed. Such a first step S1 is useful for grasping the pitch noise.

In the method for determining the arrangement of the pattern constituent unit 4 of the present embodiment, after the first step S1, the second step S2 for replacing the first pattern train 5A with the first pulse train 11 is performed. In the second step S2, the first pulse train 11 is arranged in the order of the arrangement of the first pattern constituent unit 4A with an interval G corresponding to the length D1 of the first pattern constituent unit 4A in the tire circumferential direction. It is desirable to replace with.

In the method for determining the arrangement of the pattern constituent unit 4 of the present embodiment, the third step S3 for acquiring the second pulse train 13 is performed after the second step S2. In the third step S3, it is desirable to acquire the second pulse train 13 in which the first pulses 10 of the adjacent Nt / GCD of the first pulse train 11 are added to form the second pulse 12 of the N / GCD. In such a third step S3, the pitch noise in consideration of the case where the length D2 in the tire circumferential direction of the second pattern constituent unit 4B is different from the length D1 in the tire circumferential direction of the first pattern constituent unit 4A is grasped. be able to.

In the method for determining the arrangement of the pattern constituent unit 4 of the present embodiment, the fourth step S4 for determining the arrangement of the first pattern constituent unit 4A is performed after the third step S3. In the fourth step S4, the first pattern is configured so that the maximum value F _{max of the amplitude F k} of the 1st to kth order obtained by Fourier transforming the second pulse train 13 by the above equation (1) satisfies the above equation (2). It is desirable to determine the sequence of unit 4A.

In such a fourth step S4, since the maximum value F _{max of the amplitude F k in} consideration of the tread pattern 3 is defined as in the above equation (2), the pattern constituent unit of the tire 1 with further reduced pitch noise. The sequence of 4 can be determined.

Next, the design method of the tire 1 of the present embodiment will be described with reference to FIGS. 1 to 7.
The method for designing the tire 1 of the present embodiment is a method for designing the tire 1 in which the tread portion 2 is provided with the tread pattern 3 including the first pattern row 5A and the second pattern row 5B. In the first pattern row 5A of the present embodiment, at least two types of first pattern constituent units 4A having different lengths D1 in the tire circumferential direction are arranged in the tire circumferential direction. In the second pattern row 5B, a plurality of second pattern constituent units 4B are arranged in the tire circumferential direction.

In the present embodiment, the total number Nt of the first pattern constituent units 4A in one lap of the tire and the total number N of the second pattern constituent units 4B in one lap of the tire have the greatest common divisor GCD other than 1. The method for determining the arrangement of the pattern constituent unit 4 of the present embodiment targets the tread pattern 3 including such a pattern sequence 5.

In the design method of the tire 1 of the present embodiment, first, the first pattern constituent unit 4A is replaced with the first pulse 10 having a size B corresponding to the length D1 of the first pattern constituent unit 4A in the tire circumferential direction. The first step S1 is performed. Such a first step S1 is useful for grasping the pitch noise.

In the design method of the tire 1 of the present embodiment, after the first step S1, the second step S2 for replacing the first pattern train 5A with the first pulse train 11 is performed. In the second step S2, the first pulse train 11 is arranged in the order of the arrangement of the first pattern constituent unit 4A with an interval G corresponding to the length D1 of the first pattern constituent unit 4A in the tire circumferential direction. It is desirable to replace with.

In the design method of the tire 1 of the present embodiment, the third step S3 for acquiring the second pulse train 13 is performed after the second step S2. In the third step S3, it is desirable to acquire the second pulse train 13 in which the first pulses 10 of the adjacent Nt / GCD of the first pulse train 11 are added to form the second pulse 12 of the N / GCD. In such a third step S3, the pitch noise in consideration of the case where the length D2 in the tire circumferential direction of the second pattern constituent unit 4B is different from the length D1 in the tire circumferential direction of the first pattern constituent unit 4A is grasped. be able to.

In the design method of the tire 1 of the present embodiment, after the third step S3, the maximum value F _{max of the amplitude F k} of the 1st to kth order obtained by Fourier transforming the second pulse train 13 by the above equation (1) is obtained. The fourth step S4 for determining the arrangement of the first pattern constituent unit 4A so as to satisfy the above formula (2) is performed.

In such a fourth step S4, since the maximum value F _{max of the amplitude F k in} consideration of the tread pattern 3 is defined as in the above equation (2), the tire 1 with further reduced pitch noise is designed. Can be done.

Next, the manufacturing method of the tire 1 of the present embodiment will be described with reference to FIGS. 1 to 7.
The method for manufacturing the tire 1 of the present embodiment is a method for manufacturing the tire 1 in which the tread portion 2 is provided with the tread pattern 3 including the first pattern row 5A and the second pattern row 5B. In the first pattern row 5A of the present embodiment, at least two types of first pattern constituent units 4A having different lengths D1 in the tire circumferential direction are arranged in the tire circumferential direction. In the second pattern row 5B, a plurality of second pattern constituent units 4B are arranged in the tire circumferential direction.

In the present embodiment, the total number Nt of the first pattern constituent units 4A in one lap of the tire and the total number N of the second pattern constituent units 4B in one lap of the tire have the greatest common divisor GCD other than 1. The method for determining the arrangement of the pattern constituent unit 4 of the present embodiment targets the tread pattern 3 including such a pattern sequence 5.

In the method for manufacturing the tire 1 of the present embodiment, first, the first pattern constituent unit 4A is replaced with a first pulse 10 having a size B corresponding to the length D1 of the first pattern constituent unit 4A in the tire circumferential direction. The first step S1 is performed. Such a first step S1 is useful for grasping the pitch noise.

In the method for manufacturing the tire 1 of the present embodiment, after the first step S1, the second step S2 for replacing the first pattern row 5A with the first pulse train 11 is performed. In the second step S2, the first pulse train 11 is arranged in the order of the arrangement of the first pattern constituent unit 4A with an interval G corresponding to the length D1 of the first pattern constituent unit 4A in the tire circumferential direction. It is desirable to replace with.

In the method for manufacturing the tire 1 of the present embodiment, the second step S2 is followed by the third step S3 for acquiring the second pulse train 13. In the third step S3, it is desirable to acquire the second pulse train 13 in which the first pulses 10 of the adjacent Nt / GCD of the first pulse train 11 are added to form the second pulse 12 of the N / GCD. In such a third step S3, the pitch noise in consideration of the case where the length D2 in the tire circumferential direction of the second pattern constituent unit 4B is different from the length D1 in the tire circumferential direction of the first pattern constituent unit 4A is grasped. be able to.

In the method for manufacturing the tire 1 of the present embodiment, after the third step S3, the maximum value F _{max of the amplitude F k} of the 1st to kth order obtained by Fourier transforming the second pulse train 13 by the above equation (1) is obtained. The fourth step S4 for forming the first pattern train 5A satisfying the above formula (2) is performed.

In such a fourth step S4, since the maximum value F _{max of the amplitude F k in} consideration of the tread pattern 3 is defined as in the above equation (2), the tire 1 with further reduced pitch noise can be manufactured. Can be done.

Although the particularly preferable embodiments of the present invention have been described in detail above, the present invention is not limited to the illustrated embodiments, and can be modified into various embodiments.

A tire having the arrangement of the pattern constituent units shown in FIG. 1 was prototyped based on the specifications of Tables 1 and 2.

The prototype tires were mounted on all wheels of the actual vehicle, and the in-vehicle noise test was conducted as a sound pressure test and a sensory test. The common specifications and test methods for the prototype tires are as follows.

<Common specifications>
Tire size: 215 / 60R16 95T
Rim size: 16 x 6.5J
Air pressure: 230 kPa
Total number of first pattern constituent units Nt: 72
Number of types of first pattern constituent unit m: 5 types

<Sound pressure test>
Using a large domestic passenger car equipped with prototype tires on all wheels, the sound pressure of the sound inside the vehicle was measured when traveling on a test course for road noise measurement at 45 km / h, 60 km / h, and 120 km / h. The result is an index with the comparative example as 100, and the smaller the value, the smaller the sound pressure and the better the noise performance.

<Sensory test>
The sound inside the car when traveling on a test course for road noise measurement at 45 km / h, 60 km / h and 120 km / h using a large domestic passenger car equipped with prototype tires was evaluated by the sensuality of the test driver. The results are evaluated by the 10-point method, and the larger the value, the smaller the noise inside the vehicle and the better the noise performance.

The test results are shown in Table 2.

As a result of the test, it was confirmed that the tire of the example was superior in noise performance to the tire of the comparative example and reduced the pitch noise.

1 Tire 2 Tread part 3 Tread pattern 4 Pattern constituent unit 5 Pattern train 10 Pulse 11 1st pulse train 12 2nd pulse train 13 3rd pulse train

Claims (11)

A tire with a tread
In the tread portion, at least two types of first pattern constituent units having different lengths in the tire circumferential direction are arranged in the tire circumferential direction, and a plurality of second pattern constituent units are arranged in the tire circumferential direction. A tread pattern including the second pattern row is provided,
The total number Nt of the first pattern constituent units in one lap of the tire and the total number N of the second pattern constituent units in one lap of the tire have a greatest common divisor GCD other than 1.
The first pattern constituent unit is replaced with a first pulse having a size corresponding to the length of the first pattern constituent unit in the tire circumferential direction.
The first pattern train is replaced with a first pulse train in which the first pulse is arranged in the order of the arrangement of the first pattern constituent units at intervals according to the length of the first pattern constituent units in the tire circumferential direction. death,
When a second pulse train obtained by adding the first pulses of Nt / GCD adjacent to the first pulse train to form a second pulse of N / GCD is obtained.
The maximum value F _{max of the amplitude F k} of the 1st to kth order obtained by Fourier transforming the second pulse train by the following equation (1) satisfies the following equation (2).
tire.

here,
L: Tire circumference variable (sum of the ratio of the lengths of all the first pattern constituent units in one tire circumference)
k: Natural number from 1 to 2N X (j): Jth pulse position from the starting point of the second pulse train (sum of intervals of the second pulse from the starting point to the jth pulse)
P (j): Magnitude of the jth second pulse of the second pulse train m: Number of types of the first pattern constituent unit The tire according to claim 1, wherein the second pulse train is formed by adding two adjacent pulses of the first pulse train to form one second pulse. The magnitude of the first pulse is the center of the tire circumferential length of the first pattern constituent unit corresponding to the first pulse, and the tire circumferential length of at least two types of the first pattern constituent units. The tire according to claim 1 or 2, defined as a ratio to a value. The tire according to claim 3, wherein the ratio is 0.05 to 0.35. Wherein among 1~k following amplitude _{F k,} the amplitude _{F 1} of the primary number is 2.0 or less, a tire according to any one of claims 1 to 4. Wherein among 1~k following amplitude _{F k,} the amplitude _{F 1} of the primary number is 1.0 or less, a tire according to any one of claims 1 to 4. The tire according to any one of claims 1 to 6, wherein among the amplitudes F _{k of the 1st to kth} orders, the amplitude F k of 2/3 or more of the maximum value F _{max is not continuous in adjacent orders.} The tire according to any one of claims 1 to 7, wherein the total number Nt of the first pattern constituent units in one round of the tire is 30 to 90. In the tread portion, at least two types of first pattern constituent units having different lengths in the tire circumferential direction are arranged in the tire circumferential direction, and a plurality of second pattern constituent units are arranged in the tire circumferential direction. A method for manufacturing a tire having a tread pattern including a second pattern row.
When the total number Nt of the first pattern constituent units in one lap of the tire and the total number N of the second pattern constituent units in one lap of the tire have a greatest common divisor GCD other than 1.
The first step of replacing the first pattern constituent unit with a first pulse having a size corresponding to the length of the first pattern constituent unit in the tire circumferential direction.
The first pattern train is replaced with a first pulse train in which the first pulse is arranged in the order of the arrangement of the first pattern constituent units at intervals according to the length of the first pattern constituent units in the tire circumferential direction. The second step to do
A third step of adding the first pulses of Nt / GCD adjacent to the first pulse train to obtain a second pulse train of N / GCD second pulses.
The fourth pattern train is formed so that the maximum value F _{max of the first- kth-} order amplitude Fk obtained by Fourier transforming the second pulse train with the following formula (1) satisfies the following formula (2). Including the process,
Tire manufacturing method.

here,
L: Tire circumference variable (sum of the ratio of the lengths of all the first pattern constituent units in one tire circumference)
k: Natural number from 1 to 2N X (j): Jth pulse position from the starting point of the second pulse train (sum of intervals of the second pulse from the starting point to the jth pulse)
P (j): Magnitude of the jth second pulse of the second pulse train m: Number of types of the first pattern constituent unit In the tread portion, at least two types of first pattern constituent units having different lengths in the tire circumferential direction are arranged in the tire circumferential direction, and a plurality of second pattern constituent units are arranged in the tire circumferential direction. It is a method for designing a tire provided with a tread pattern including a second pattern row.
When the total number Nt of the first pattern constituent units in one lap of the tire and the total number N of the second pattern constituent units in one lap of the tire have a greatest common divisor GCD other than 1.
The first step of replacing the first pattern constituent unit with a first pulse having a size corresponding to the length of the first pattern constituent unit in the tire circumferential direction.
The first pattern train is replaced with a first pulse train in which the first pulse is arranged in the order of the arrangement of the first pattern constituent units at intervals according to the length of the first pattern constituent units in the tire circumferential direction. The second step to do
A third step of adding the first pulses of Nt / GCD adjacent to the first pulse train to obtain a second pulse train of N / GCD second pulses.
The arrangement of the first pattern structural unit is determined so that the maximum value F _{max of the amplitude F k} of the 1st to kth order obtained by Fourier transforming the second pulse train by the following equation (1) satisfies the following equation (2). Including the fourth step of
How to design a tire.

here,
L: Tire circumference variable (sum of the ratio of the lengths of all the first pattern constituent units in one tire circumference)
k: Natural number from 1 to 2N X (j): Jth pulse position from the starting point of the second pulse train (sum of intervals of the second pulse from the starting point to the jth pulse)
P (j): Magnitude of the jth second pulse of the second pulse train m: Number of types of the first pattern constituent unit It is a method for determining the arrangement in the tire circumferential direction of the pattern constituent units constituting the pattern sequence with respect to the pattern sequence included in the tread pattern of the tire.
The pattern sequence includes a first pattern sequence in which at least two types of first pattern constituent units having different lengths in the tire circumferential direction are arranged in the tire circumferential direction, and a plurality of second pattern constituent units are arranged in the tire circumferential direction. Including the second pattern sequence
When the total number Nt of the first pattern constituent units in one lap of the tire and the total number N of the second pattern constituent units in one lap of the tire have a greatest common divisor GCD other than 1.
The first step of replacing the first pattern constituent unit with a first pulse having a size corresponding to the length of the first pattern constituent unit in the tire circumferential direction.
The first pattern train is replaced with a first pulse train in which the first pulse is arranged in the order of the arrangement of the first pattern constituent units at intervals according to the length of the first pattern constituent units in the tire circumferential direction. The second step to do
A third step of adding the first pulses of Nt / GCD adjacent to the first pulse train to obtain a second pulse train of N / GCD second pulses.
The arrangement of the first pattern structural unit is determined so that the maximum value F _{max of the amplitude F k} of the 1st to kth order obtained by Fourier transforming the second pulse train by the following equation (1) satisfies the following equation (2). Including the fourth step of
How to determine the arrangement of pattern constituent units.

here,
L: Tire circumference variable (sum of the ratio of the lengths of all the first pattern constituent units in one tire circumference)
k: Natural number from 1 to 2N X (j): Jth pulse position from the starting point of the second pulse train (sum of intervals of the second pulse from the starting point to the jth pulse)
P (j): Magnitude of the jth second pulse of the second pulse train m: Number of types of the first pattern constituent unit

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