JP3581188B2 - Pneumatic tires for passenger cars - Google Patents

Description

【００２４】
【表２】

【００２５】
表１，２から明らかなように、ビードフィラーの子午線断面における断面高さＬを内周端のフィラー幅ｂとタイヤ断面高さＳＨとの関係において、
０．２ＳＨ〔（ｎ１＋１）（ｎ１＋２）（ｎ１＋３）／２ｂ〕^１／３ ≦Ｌ≦０．５ＳＨ〔（ｎ２＋１）（ｎ２＋２）（ｎ２＋３）／２ｂ〕^１／３
にし、かつビードフィラーの外周端からの距離ｘにおけるフィラー幅ｂ_ｘ を断面高さＬと内周端のフィラー幅ｂとの関係において、
ｂ（ｘ／Ｌ）^ｎ１≦ｂ_ｘ ≦ｂ（ｘ／Ｌ）^ｎ２
ｎ１＝４／３、ｎ２＝２／３
にした本発明タイヤは、４０Ｈｚ付近と１００Ｈｚ付近のロードノイズをいずれも悪化させることなく、バランスして改善することができるのが判る。
【００２６】
また、定数ｎ２を１以上の範囲にして、ビードフィラーのフィラー幅ｂ_ｘ を設定することにより、４０Ｈｚ付近のロードノイズを悪化させることなく、１００Ｈｚ付近のロードノイズを有効に改善することができるのが判る。
また、定数ｎ１を１以下の範囲にして、ビードフィラーのフィラー幅ｂ_ｘ を設定することにより、１００Ｈｚ付近のロードノイズを悪化させることなく、４０Ｈｚ付近のロードノイズを有効に改善することができるのが判る。
【００２７】
また、他のタイヤ、例えば、タイヤサイズが１９５／５５Ｒ１５のタイヤ等についても、上述と同様にして騒音性能の評価試験を実施したところ、上記と同様の結果を得た。
【００２８】
【発明の効果】
上述のように本発明は、ビードコアの外周側に当接配置する一層構造のビードフィラーの断面高さＬとフィラー幅ｂ _x を上記のように特定することにより、タイヤ径方向の剛性を従来と同等以下に低下させる一方、タイヤ周方向の剛性を従来と同等以上に確保することができるので、４０Ｈｚ付近と１００Ｈｚ付近のロードノイズをどちらも悪化させることなくバランスして改善することができる。
【図面の簡単な説明】
【図１】本発明の乗用車用空気入りタイヤの一例を示す子午線半断面図である。
【図２】本発明の乗用車用空気入りタイヤに用いられるビードフィラーの子午線断面を示す説明図である。
【図３】本発明の乗用車用空気入りタイヤの他の例を示す子午線半断面図である。
【図４】本発明の乗用車用空気入りタイヤの更に他の例を示す子午線半断面図である。
【符号の説明】
１ トレッド部 ２ ビード部
３ サイドウォール部 ４，４’ カーカス
５ ビードコア ６ ビードフィラー
６ａ 外周端 ６ｂ 内周端[0001]
[Industrial applications]
The present invention relates to a pneumatic tire for use in a passenger car, and more particularly, to a pneumatic tire for a passenger car in which road noise at around 40 Hz and around 100 Hz is balanced and improved without deterioration.
[0002]
[Prior art]
In recent years, further reduction of the road noise has been demanded. In particular, it has been required to improve road noise at a frequency of 40 Hz and around 100 Hz. It is known that the transmission rate of the vibration by the tire increases when the frequency of the external force matches (resonates with) the natural frequency of the tire. Therefore, the mechanical factors of the tire constituent materials that control the natural frequency of the tire are known. Is changed, road noise for a specific frequency can be reduced. From such findings, it is understood that road noise around 40 Hz can be improved by increasing the circumferential rigidity of the tire, and road noise around 100 Hz can be improved by reducing the radial rigidity of the tire. know.
[0003]
Conventionally, the road noise around 40 Hz and the road noise around 100 Hz have been improved by individually changing different tire members. However, in these conventional improvement means, when the circumferential rigidity of the tire is increased to improve the road noise around 40 Hz, the radial rigidity increases, the road noise around 100 Hz deteriorates, and the radial rigidity of the tire decreases. When the noise is reduced to improve the road noise around 100 Hz, it is difficult to secure the rigidity in the circumferential direction, and the road noise around 40 Hz is deteriorated.
[0004]
[Problems to be solved by the invention]
SUMMARY OF THE INVENTION An object of the present invention is to provide a pneumatic tire for a passenger car, which can balance and improve road noise at around 40 Hz and around 100 Hz without deterioration.
[0005]
[Means for Solving the Problems]
In order to achieve the above object, the present invention embeds a bead core in each of the left and right bead portions, arranges a bead filler having a one-layer structure on the outer peripheral side of the bead core, and attaches both ends of the carcass disposed inside the tire to the bead cores. A pneumatic tire for a passenger car folded around from the inside to the outside of the tire, wherein a cross-sectional height of the bead filler at a meridian cross-section is L, a filler width at an inner peripheral end is b, and a meridian cross-section at a distance x from an outer peripheral end. Where the filler width is b _x , the tire section height is SH, the constant n1 is 4/3, and the constant n2 is 2/3, the following formula is satisfied.
0.2SH [(n1 + 1) (n1 + 2) (n1 + 3) / 2b] ^1/3 ≦ L
≤0.5SH [(n2 + 1) (n2 + 2) (n2 + 3) / 2b] ^1/3 (1)
b (x / L) ⁿ¹ ≦ b _x ≦ b (x / L) ⁿ² (2)
[0006]
As described above, the cross-sectional height of the bead filler is set as in the above equation (1) to make it higher than before, and the width is set by the above equation (2) from the outer peripheral end to the inner peripheral end in relation to the height. By forming the bead filler in a range that is narrower in the tire radial direction than the cross-sectional shape that is generally adopted, the rigidity of the bead filler in the height direction is equal to or less than the conventional one. The rigidity in the tire radial direction can be reduced by decreasing the radial rigidity in the tire radial direction. Can be secured. Therefore, only by specifying the meridian cross-sectional shape of the bead filler, without changing a plurality of tire materials as in the related art, it is necessary to balance and improve road noise at around 40 Hz and around 100 Hz without any deterioration. Becomes possible.
[0007]
Hereinafter, the configuration of the present invention will be described in detail with reference to the accompanying drawings.
FIG. 1 shows an example of a pneumatic tire for a passenger car according to the present invention, wherein 1 is a tread portion, 2 is a bead portion, and 3 is a sidewall portion. Left and right sidewall portions 3 are connected to the left and right bead portions 2 and extend outward (outer diameter side) in the tire radial direction, and a tread portion 1 extending in the tire circumferential direction between the left and right sidewall portions 3. Is provided.
[0008]
The carcass 4 is disposed inside the tire, and both end portions of the carcass 4 are folded back from the inside of the tire to the outside around a bead core 5 having a rectangular cross section embedded in both right and left bead portions 2. The folded portions 4a at both ends are folded so as to exceed the outer peripheral end 6a of the bead filler 6 having a single layer structure arranged on the outer peripheral side of the bead core 5, and the central portion of the side wall portion 3 is sandwiched so as to sandwich the bead filler 6. It is arranged until. Further, a plurality of belt layers 8 are provided on the outer peripheral side of the tread portion 1 of the carcass 4.
[0009]
In the present invention, in the pneumatic tire for a passenger car having the above-described configuration, the meridian cross-sectional shape of the ring-shaped bead filler 6 disposed on the outer peripheral side of the bead core 5 is changed from the outer peripheral end 6a to the inner peripheral end 6b contacting the bead core 5. The cross-sectional height L of the bead filler 6, which is gradually increased toward the side and is indicated by the length in the tire radial direction from the outer peripheral end 6 a to the inner peripheral end 6 b thereof, is higher than that of the conventional bead filler. It has a high filler configuration. The cross-sectional shape becomes a vertex at the outer peripheral end 6a, and the inner peripheral end 6b abuts on the entire outer peripheral side of the bead core 5 on the outer side in the tire radial direction of the cross section of the bead core 5 (the inner peripheral end surface of the bead filler 6 is the outer peripheral surface of the bead core 5). Contacting the entire surface).
[0010]
The cross-sectional height L of the bead filler is defined as a filler width b of the inner peripheral end 6b of the bead filler and a distance between the inner peripheral end of the bead portion 2 and the tread surface at the center line CL of the tread portion 1 in the tire radial direction. In relation to the defined tire section height SH,
0.2SH [(n1 + 1) (n1 + 2) (n1 + 3) / 2b] ^1/3 ≦ L ≦ 0.5SH [(n2 + 1) (n2 + 2) (n2 + 3) / 2b] ^1/3
Is set in the range.
[0011]
Further, the filler width b _x of the meridian section at a distance x in the tire radial direction from the outer peripheral end 6a to the inner peripheral end 6b of the bead filler is represented by the relationship between the filler width b of the inner peripheral end 6b and the sectional height L,
b (x / L) ⁿ¹ ≦ b _x ≦ b (x / L) ⁿ²
Is within the range. However, the n1 and n2 are constants for defining the filler width b _x and section height L, and n1 = 4/3, n2 = 2/3.
[0012]
As described above, by making the cross-sectional height L of the bead filler 6 higher than before, and forming the width from the outer peripheral end to the inner peripheral end in relation to the cross-sectional height L within the range shown by the above equation. The bead filler 6 has a meridian cross-sectional shape that is longer than a generally employed cross-sectional shape, and the rigidity in the height direction of the bead filler 6 is equal to or less than that of a conventional one, thereby reducing the rigidity in the tire radial direction. On the other hand, the secondary moment of area relating to the circumferential rigidity of the ring-shaped bead filler 6 can be secured at a level substantially equal to or higher than the conventional level, and the tire circumferential rigidity can be increased. Therefore, only by specifying the meridian cross-sectional shape of the bead filler 6, without changing a plurality of tire materials as in the related art, the load noise around 40 Hz and around 100 Hz is not deteriorated in either one, and the balance is reduced. Can be improved.
[0013]
When the cross-sectional height L of the bead filler is smaller than 0.2 SH [(n1 + 1) (n1 + 2) (n1 + 3) / 2b] ^1/3 , the circumferential rigidity of the bead filler 6 is maintained at the same level as the conventional one. becomes difficult, 0.5SH [(n2 + 1) (n2 + 2) (n2 + 3) / 2b ] exceeds ^4/3, it is impossible to achieve road noise improvement around 100Hz reduce the tire radial direction rigidity.
[0014]
On the other hand, if the constant n1 exceeds 4/3, the bead filler 6 becomes too thin and exceeds the buckling limit , so that it is impossible to secure the rigidity in the tire circumferential direction, and road noise near 40 Hz is significantly deteriorated. If the constant n2 is smaller than 2/3, the width of the bead filler 6 becomes too large, and it becomes difficult to reduce the rigidity in the tire radial direction.
[0015]
Without deteriorating the road noise in the vicinity of 40 Hz, to improve the road noise in the vicinity of 100Hz may have to constant n2 to n2 = 1, thereby effectively narrowing the filler width b _x of the bead filler 6 Thus, the rigidity in the tire radial direction can be effectively reduced.
Further, in order to improve the road noise around 40 Hz without deteriorating the road noise around 100 Hz, it is preferable to set the constant n1 to n1 = 1, thereby making the rigidity in the tire radial direction equal to or less than that of the conventional tire. However, the second moment of area of the bead filler 6 can be made larger than before, and the rigidity in the tire circumferential direction can be increased.
[0016]
In the present invention, in the above-described embodiment, the meridian cross-sectional shape of the bead filler 6 is formed so as to gradually increase in width from the outer peripheral end 6a to the inner peripheral end 6b side. However, the present invention is not limited thereto, and the filler width b _x May be within the range of the above expression.
FIG. 3 shows another example of the pneumatic tire for a passenger car according to the present invention. In the above-described embodiment, the folded portion 4a at both ends of the carcass, which reaches the center of the sidewall portion 3, is formed by a low turn that abuts the inner peripheral end 6A of the bead filler 6 disposed on the outer peripheral side of the bead core 5. It is an up structure. By adopting a low turn-up structure in which the folded length is reduced so that the folded portions 4a at both ends of the carcass abut on the inner peripheral end 6A of the bead filler 6 as in the above-described embodiment, Rigidity in the tire circumferential direction can be reduced to further improve road noise in the vicinity of 100 Hz as compared with the case where both ends of the carcass are largely folded, and the tire is reduced in weight by the shortened length of the folded portion 4a. Can be achieved.
[0017]
FIG. 4 shows still another example of the pneumatic tire for a passenger car according to the present invention. In the embodiment of FIG. 3 described above, one layer of carcass 4 'is further provided outside the one layer of carcass 4 having a low turn-up structure. The outer carcass 4 ′ is rolled down so that both end portions 4 ′ a come into contact with the outside of the folded portion 4 a of the inner carcass 4 while contacting the outside of the bead filler 6, and are folded around the bead core 5. It is not floating structure.
[0018]
Thus, even in the tire having the configuration using the low turn-up structure and the floating structure, the cross-sectional height L of the bead filler 6 in the meridian cross section and the cross-sectional height of the bead filler 6 at the distance x from the outer peripheral end 6a of the bead filler 6 are determined. a filler width b _x by setting as described above, it is possible to achieve the same effect.
Further, in addition to the effect of the tire having the configuration shown in FIG. 3, both ends 4 ′ a of the outer carcass 4 ′ are rolled down outside the inner carcass 4 and have a floating structure that is not folded around the bead core 5. Therefore, the rigidity in the tire radial direction can be made lower than in the case where both ends of the carcass 4 ′ are turned back, thereby contributing to the improvement of road noise around 100 Hz. 'Is easy to install, so that productivity can be improved.
[0019]
In the embodiment of FIG. 4, the inner carcass 4 has a low turn-up structure in which the folded portion 4a is located between the outer peripheral end 6a and the inner peripheral end 6b of the bead filler 6. Alternatively, the folded portion 4a of the carcass 4 may extend beyond the bead filler outer peripheral end 6a.
[0020]
【Example】
Tire size is 175 / 70R13, tire configuration is common in FIG. 1, and as shown in Table 1, present invention tires 1 to 3 and comparative tire 1 in which the cross-sectional height L (mm) in the meridian cross-section of the bead filler are respectively changed. , 2 and a conventional tire having a conventional sectional height L. In each of the test tires, the filler width b at the inner peripheral end of the bead filler is 6 mm, and the tire section height SH is 124 mm. The filler width b _x (mm) of the tire of the present invention and the comparative tire is b (x / L) ^1.2 , and the filler width b _x (mm) of the conventional tire is b (x / L) ^{0.5-0. 8}
[0021]
The tires 4 to 6 of the present invention in which the tire size and the tire configuration were the same as above and the filler width b _x (mm) of the meridian cross section at the distance x from the outer peripheral end of the bead filler were respectively changed, and the comparative tires 3 and 4 And produced respectively. Constant that determines the filler width b _x are as shown in Table 2. In each of the test tires, the filler width b and the tire section height SH are the same as described above, and the section height L of the bead filler is as shown in Table 2.
[0022]
Each of these test tires was mounted on a rim having a rim size of 13 × 5JJ, mounted on a 1500 cc passenger car at an air pressure of 2.0 kgf / cm ² , and evaluated for noise performance under the following measurement conditions. The results shown in Table 2 were obtained.
Noise performance The vehicle travels on a paved road surface at a speed of 60 km / h, and the sound pressure level of 40 Hz and 100 Hz is measured by a microphone attached to a driver's seat window side position, and evaluated with ± [dB] based on a conventional tire. . As the sign is + and the numerical value is larger, the sound pressure level is higher than that of the conventional tire and the noise performance is inferior, and as the sign is-and the numerical value is larger, the sound pressure level is lower than the conventional tire and the noise performance is lower. Are better.
[0023]
[Table 1]

[0024]
[Table 2]

[0025]
As is clear from Tables 1 and 2, the cross-sectional height L of the bead filler in the meridian cross-section is represented by the relationship between the filler width b at the inner peripheral end and the tire cross-sectional height SH.
0.2SH [(n1 + 1) (n1 + 2) (n1 + 3) / 2b] ^1/3 ≦ L ≦ 0.5SH [(n2 + 1) (n2 + 2) (n2 + 3) / 2b] ^1/3
And the filler width b _x at a distance x from the outer peripheral end of the bead filler is defined as a relation between the sectional height L and the filler width b at the inner peripheral end,
b (x / L) ⁿ¹ ≦ b _x ≦ b (x / L) ⁿ²
n1 = 4/3, n2 = 2/3
It can be seen that the tire according to the present invention can be improved in a balanced manner without deteriorating the road noise at around 40 Hz and around 100 Hz.
[0026]
Moreover, the constant n2 in the one or more ranges, by setting the filler width b _x of the bead filler without deteriorating the road noise in the vicinity of 40 Hz, can be effectively improved road noise around 100Hz I understand.
Further, in the range of the constant n1 1 below, by setting the filler width b _x of the bead filler without deteriorating the road noise in the vicinity of 100 Hz, can be effectively improved road noise around 40Hz I understand.
[0027]
In addition, other tires, for example, tires having a tire size of 195 / 55R15, were subjected to noise performance evaluation tests in the same manner as described above, and the same results as above were obtained.
[0028]
【The invention's effect】
The present invention as described above, by the section height L and filler width b _x of the bead filler layer structure in contact disposed on the outer peripheral side of the bead core is specified above, the conventional rigidity in the tire radial direction On the other hand, the tire can be reduced to the same or less, and the rigidity in the tire circumferential direction can be secured to be equal to or more than that of the conventional tire, so that the road noise around 40 Hz and 100 Hz can be balanced and improved without deteriorating both.
[Brief description of the drawings]
FIG. 1 is a meridian half sectional view showing an example of a pneumatic tire for a passenger car according to the present invention.
FIG. 2 is an explanatory diagram showing a meridional section of a bead filler used for a pneumatic tire for a passenger car according to the present invention.
FIG. 3 is a meridian half sectional view showing another example of the pneumatic tire for a passenger car of the present invention.
FIG. 4 is a meridian half sectional view showing still another example of the pneumatic tire for a passenger car according to the present invention.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Tread part 2 Bead part 3 Side wall part 4,4 'Carcass 5 Bead core 6 Bead filler 6a Outer end 6b Inner end

Claims (4)

A bead core is buried in each of the left and right bead portions, a bead filler having a single layer structure is arranged on the outer peripheral side of the bead core, and both end portions of the carcass arranged inside the tire are turned around the bead core from the inside of the tire to the outside. Pneumatic tires for passenger cars,
The cross-sectional height of the bead filler at the meridian cross-section is L, the filler width at the inner peripheral end is b, the filler width at the meridian cross-section at a distance x from the outer peripheral end is b _x , the tire cross-sectional height is SH, and the constant n1 is 4 / 3. A pneumatic tire for a passenger car that satisfies the following expression, where the constant n2 is 2/3 .
0.2SH [(n1 + 1) (n1 + 2) (n1 + 3) / 2b] ^1/3 ≦ L
≤0.5SH [(n2 + 1) (n2 + 2) (n2 + 3) / 2b] ^1/3
b (x / L) ⁿ¹ ≦ b _x ≦ b (x / L) ⁿ² The pneumatic tire for a passenger car according to claim 1, wherein the constant n2 is set to 1 instead of 2/3 . The pneumatic tire for a passenger car according to claim 1, wherein the constant n1 is set to 1 instead of 4/3 . 4. The pneumatic tire for a passenger car according to claim 1, wherein a meridian cross-sectional shape of the bead filler is gradually widened from an outer peripheral end thereof toward an inner peripheral end contacting the bead core.

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