JP2014240257A

JP2014240257A - Pneumatic tire

Info

Publication number: JP2014240257A
Application number: JP2013124096A
Authority: JP
Inventors: 隆弘川原; Takahiro Kawahara; 亜希夫草野; Akio Kusano
Original assignee: Bridgestone Corp
Current assignee: Bridgestone Corp
Priority date: 2013-06-12
Filing date: 2013-06-12
Publication date: 2014-12-25
Anticipated expiration: 2033-06-12
Also published as: JP6077944B2

Abstract

PROBLEM TO BE SOLVED: To provide a new pneumatic tire that can effectively prevent slipping of a rim during load rolling of the tire to keep a favorable fitting condition with the rim and does not impair steering stability and ride comfort.SOLUTION: A pneumatic tire 1, in an attitude in which the tire is mounted in an unloaded condition where the tire is mounted on an applied rim 14 and a prescribed air pressure is filled, includes: a first curved portion 11 having curvature where a lateral periphery shape of the tire protrudes toward outside of the tire in the tire widthwise cross-section view; a second curved portion 12 that is connected to inside in a tire radial direction of the first curved portion and has curvature where the shape protrudes toward inside of the tire; and a third curved portion 13 that is connected to inside in the tire radial direction of the second curved portion and has curvature where the shape protrudes toward outside of the tire, where the first to the third curved portions satisfy predetermined conditions.

Description

本発明は、空気入りタイヤに関し、特に、負荷転動時におけるリムずれを有効に防止して、リムとの好適なフィット状態を保つことが可能な空気入りタイヤに関する。 The present invention relates to a pneumatic tire, and more particularly to a pneumatic tire capable of effectively preventing rim displacement during load rolling and maintaining a suitable fit state with a rim.

一般に、空気入りタイヤをリムに装着したとき、リムフランジと接触する部分であるビード部とこれに隣接するサイドウォール部のタイヤの側周面の輪郭形状は、例えば図４に示すように、適用リム２４に装着し所定空気圧を充填した無負荷状態におけるタイヤ装着姿勢にて、所定Ｃ点から所定Ｂ点までの間、所定曲率半径Ｒ１を有しタイヤ外方に向かって凸となる曲率を持つ第１の曲線部２１を有するように形成される。なお、図４においてはタイヤの側周面の輪郭形状をわかりやすくするため、適用リム２４を離して描いている。 In general, when a pneumatic tire is mounted on a rim, the contour shape of the side circumferential surface of the bead portion which is a portion in contact with the rim flange and the side wall portion adjacent to the bead portion is applied, for example, as shown in FIG. The tire is mounted on the rim 24 and filled with a predetermined air pressure. When the tire is mounted in a no-load state, it has a predetermined radius of curvature R1 from the predetermined point C to the predetermined point B and has a curvature that protrudes outward from the tire. The first curved portion 21 is formed. In FIG. 4, the applied rim 24 is drawn away so that the contour shape of the side peripheral surface of the tire can be easily understood.

ここで、符号２１ａは、第１の曲線部２１を一部に含み上記曲率半径Ｒ１を有する仮想円を示している。Ｏ１はこの仮想円の曲率中心、ＲＬはリム径ラインを示す。ここで、従来タイヤ２０を適用リム２４に装着し所定空気圧を充填した無負荷状態におけるタイヤ装着姿勢では、Ｂ点がリムフランジ２４ａと接触しているタイヤ径方向最外側位置である。 Here, the code | symbol 21a has shown the virtual circle which includes the 1st curve part 21 in part and has the said curvature radius R1. O1 represents the center of curvature of the virtual circle, and RL represents a rim diameter line. Here, in the tire mounting posture in a no-load state in which the conventional tire 20 is mounted on the applied rim 24 and filled with a predetermined air pressure, the point B is the outermost position in the tire radial direction in contact with the rim flange 24a.

このように従来タイヤにおいては、サイドウォール部からビード部のリムフランジと接触する部分までのタイヤ側周面の輪郭形状を、所定曲率半径を有する１つの曲面で構成するのが一般的である（特許文献１参照）。 As described above, in the conventional tire, the contour shape of the tire side peripheral surface from the sidewall portion to the portion contacting the rim flange of the bead portion is generally configured by one curved surface having a predetermined radius of curvature ( Patent Document 1).

特開２００７−３３１５４３号公報JP 2007-331543 A

しかしながら、このような従来タイヤでは負荷転動時、以下のような問題が生じる。図５は、図４に示す従来タイヤの部分拡大図であり、適用リムへの装着状態を示す。無負荷状態でＢ点までリムフランジ２４ａと接触している場合、所定負荷条件下での負荷転動時にはＢ点よりもタイヤ径方向外側のタイヤ側周面部分にまでくり返しリムフランジ２４ａとの接触領域が拡大する。しかし、第１の曲線部２１はタイヤ外方に向かって凸な曲率を持つ曲線部であり、タイヤは負荷転動時にリムフランジ２４ａから大きな干渉を受けることになる。つまり、負荷転動時に空気入りタイヤ２０とリム２４とのフィット状態が崩れ、リムずれが生じやすくなる。その結果、操縦安定性および乗り心地の悪化が懸念される。 However, such conventional tires have the following problems during rolling. FIG. 5 is a partially enlarged view of the conventional tire shown in FIG. When in contact with the rim flange 24a up to point B in an unloaded state, contact with the rim flange 24a is repeated until the tire side circumferential surface portion on the outer side in the tire radial direction from point B during load rolling under a predetermined load condition. The area expands. However, the first curved portion 21 is a curved portion having a curvature that is convex toward the outer side of the tire, and the tire receives a large interference from the rim flange 24a during load rolling. That is, the fitted state between the pneumatic tire 20 and the rim 24 is collapsed during load rolling, and rim displacement is likely to occur. As a result, there is a concern about steering stability and deterioration of riding comfort.

そこで本発明は、上記課題に鑑み、負荷転動時におけるリムずれを有効に防止して、リムとの好適なフィット状態を保つことが可能で、操縦安定性および乗り心地を損なわない新規な空気入りタイヤを提供することを目的とする。 Therefore, in view of the above problems, the present invention can effectively prevent rim deviation during load rolling and maintain a suitable fit state with the rim, and can provide a novel air that does not impair steering stability and riding comfort. An object is to provide a tire entering.

本発明者は、リムフランジと対向するタイヤの側周面部分に着目し、負荷転動時にリムフランジからの干渉を受けにくくするとの着想から、以下の発明を完成した。 The inventor paid attention to the side peripheral surface portion of the tire facing the rim flange, and completed the following invention from the idea that it is difficult to receive interference from the rim flange during load rolling.

すなわち、上記課題に鑑み、本発明の要旨構成は以下の通りである。
（１）適用リムに装着し所定空気圧を充填した無負荷状態におけるタイヤの装着姿勢にて、タイヤの側周面形状がタイヤ幅方向断面で見て、
タイヤ外方に向かって凸となる曲率を持つ第１の曲線部と、
該第１の曲線部のタイヤ径方向内側に連なりタイヤ内方に向かって凸となる曲率を持つ第２の曲線部と、
該第２の曲線部のタイヤ径方向内側に連なりタイヤ外方に向かって凸となる曲率を持つ第３の曲線部とを含み、
前記第１〜３の曲線部が下記に示す条件ａ〜ｅを満たすことを特徴とする空気入りタイヤ。
＜記＞
ａ．前記第１の曲線部は、
前記適用リムのリムフランジ断面の変曲点からリム径ラインに下ろした垂線の足であるＰ点からリム径ラインに対して６０°〜７０°の範囲内にある所定角度θ１で延びる第１の線分上にあって、リム径ラインからタイヤ断面高さＳＨの３５％〜５０％の範囲内にある所定高さＳＷＨ１の位置にあるＡ点と、該Ａ点よりもタイヤ径方向内側の所定位置Ｂ点とを通り、所定曲率半径Ｒ１を有する第１の仮想円のうち、前記Ａ点と同じまたは前記Ａ点よりもタイヤ径方向外側の所定位置Ｃ点から、該第１の仮想円と前記第１の線分との交点であり、前記Ａ点よりもタイヤ径方向内側に位置する交点Ｄ点までの部分である。
ｂ．前記第３の曲線部は、
前記Ｐ点からリム径ラインに対して前記θ１よりも大きい７０°〜８０°の範囲内にある所定角度θ２で延びる第２の線分上にあって、リム径ラインから前記ＳＨの４５％〜６０％の範囲内にある所定高さＳＷＨ２の位置にあるＥ点と、前記第１の仮想円と前記第２の線分との交点であるＦ点とを通り、前記曲率半径Ｒ１よりも大きい所定曲率半径Ｒ２を有する第２の仮想円上の部分であって、前記Ｄ点よりタイヤ径方向内側に位置する第２の仮想円上の所定位置Ｇ点から前記Ｆ点までの部分である。
ｃ．前記第２の曲線部は、前記Ｄ点から前記Ｇ点までを３０ｍｍ以下の所定曲率半径Ｒ３で結んだ曲線部である。
ｄ．前記Ｂ点が、前記タイヤ装着姿勢で適用リムのリムフランジと接触しているタイヤ径方向最外側位置である。
ｅ．前記ａ〜ｃに関わらず、前記Ｄ点が変曲点となる。 That is, in view of the above problems, the gist of the present invention is as follows.
(1) The tire is mounted in the applied rim and filled with a predetermined air pressure, and the tire is mounted in a no-load state.
A first curved portion having a curvature convex toward the outside of the tire;
A second curved portion having a curvature that is continuous with the inside of the first curved portion in the tire radial direction and is convex toward the inside of the tire;
A third curve portion having a curvature that is continuous to the inside in the tire radial direction of the second curve portion and is convex toward the outside of the tire,
The pneumatic tire characterized by said 1st-3rd curve part satisfy | filling conditions ae shown below.
<Note>
a. The first curved portion is
The first rim extending at a predetermined angle θ1 within a range of 60 ° to 70 ° with respect to the rim diameter line from point P, which is a foot of a perpendicular line drawn from the inflection point of the rim flange section of the applied rim to the rim diameter line. A point on the line segment and located at a predetermined height SWH1 within a range of 35% to 50% of the tire cross-section height SH from the rim diameter line, and a predetermined point on the inner side in the tire radial direction from the point A Among the first virtual circles that pass through the point B and have a predetermined radius of curvature R1, the first virtual circle is the same as the point A or from the predetermined position C point outside the point A in the tire radial direction. It is an intersection with the first line segment, and is a portion up to an intersection point D located on the inner side in the tire radial direction from the point A.
b. The third curved portion is
It is on a second line segment extending at a predetermined angle θ2 within a range of 70 ° to 80 ° larger than θ1 with respect to the rim diameter line from the point P, and 45% to SH of the SH from the rim diameter line. It passes through the point E at the position of the predetermined height SWH2 within the range of 60% and the point F that is the intersection of the first virtual circle and the second line segment, and is larger than the curvature radius R1. A portion on a second imaginary circle having a predetermined radius of curvature R2, which is a portion from a predetermined position G on the second imaginary circle located on the inner side in the tire radial direction from the point D to the point F.
c. The second curved portion is a curved portion connecting the point D to the point G with a predetermined radius of curvature R3 of 30 mm or less.
d. The point B is the outermost position in the tire radial direction in contact with the rim flange of the application rim in the tire mounting posture.
e. Regardless of a to c, the point D is an inflection point.

（２）前記第１の曲線部の曲率中心が、Ａ点を通りリム径ラインに平行な線上にあり、
前記第３の曲線部の曲率中心が、Ｅ点を通りリム径ラインに平行な線上にある上記（１）に記載の空気入りタイヤ。 (2) The center of curvature of the first curved portion is on a line passing through point A and parallel to the rim diameter line,
The pneumatic tire according to (1), wherein the center of curvature of the third curved portion is on a line passing through point E and parallel to the rim diameter line.

（３）前記Ｒ１が２０〜１００ｍｍであり、前記Ｒ２が１００〜２５０ｍｍである上記（１）または（２）に記載の空気入りタイヤ。 (3) The pneumatic tire according to (1) or (2), wherein the R1 is 20 to 100 mm and the R2 is 100 to 250 mm.

（４）前記第３の曲線部は、負荷転動時には適用リムのリムフランジとくり返し接触する部分である上記（１）〜（３）のいずれか１項に記載の空気入りタイヤ。 (4) The pneumatic tire according to any one of (1) to (3), wherein the third curved portion is a portion that repeatedly comes into contact with a rim flange of an applied rim during load rolling.

本発明によれば、負荷転動時におけるリムずれを有効に防止して、リムとの好適なフィット状態を保つことが可能で、操縦安定性および乗り心地を損なわない新規な空気入りタイヤを提供することができる。その作用については後述する。 According to the present invention, a novel pneumatic tire that can effectively prevent rim deviation during load rolling and maintain a suitable fit state with a rim and does not impair driving stability and riding comfort is provided. can do. Its operation will be described later.

本発明に従う空気入りタイヤを適用リムに装着し所定空気圧を充填した無負荷状態における、タイヤ幅方向の半断面図である。FIG. 2 is a half cross-sectional view in the tire width direction in a no-load state in which a pneumatic tire according to the present invention is mounted on an applied rim and filled with a predetermined air pressure. 本発明に従う空気入りタイヤの側周面の輪郭形状を説明するための図である。It is a figure for demonstrating the outline shape of the side peripheral surface of the pneumatic tire according to this invention. 図１に示す空気入りタイヤの要部を示す部分拡大図である。It is the elements on larger scale which show the principal part of the pneumatic tire shown in FIG. 従来の空気入りタイヤの側周面の輪郭形状を説明するための図である。It is a figure for demonstrating the outline shape of the side peripheral surface of the conventional pneumatic tire. 図４に示す従来タイヤの部分拡大図である。It is the elements on larger scale of the conventional tire shown in FIG.

以下、図面を参照しつつ本発明をより詳細に説明する。なお、同一の構成要素には原則として同一の参照番号を付して、説明を省略する。 Hereinafter, the present invention will be described in more detail with reference to the drawings. In principle, the same components are denoted by the same reference numerals, and description thereof is omitted.

図１は、本発明に従う代表的な空気入りタイヤ１を適用リムに装着し所定空気圧を充填した無負荷状態における、タイヤ幅方向の半断面図である。この実施形態において、空気入りタイヤ１は、トレッド部６（半部のみ図示）と、トレッド部６の両側部からタイヤ径方向内側に延びる一対のサイドウォール部５（片側のみ図示）と、各サイドウォール部のタイヤ径方向内側に延びるビード部４（片側のみ図示）とを備える。 FIG. 1 is a half cross-sectional view in the tire width direction in a no-load state in which a typical pneumatic tire 1 according to the present invention is mounted on an applied rim and filled with a predetermined air pressure. In this embodiment, the pneumatic tire 1 includes a tread portion 6 (only a half portion is illustrated), a pair of sidewall portions 5 (only one side is illustrated) extending from both side portions of the tread portion 6 in the tire radial direction, and each side. And a bead portion 4 (only one side is shown) extending inward in the tire radial direction of the wall portion.

また、ビード部４に埋設した一対のビードコア２（片側のみ図示）間にトロイド状に延びる少なくとも一枚のカーカスプライからなるカーカス７（図１では１プライ）を有する。図１では、カーカスプライを、一対のビードコア２およびゴム３の周りに、それぞれの側部部分を折り返した形状を示したが、本発明ではこれに限られることはない。カーカス７を構成するプライはコードゴム被覆層であり、コード材料としてはスチール、有機繊維などが例示できる。ラジアルカーカスの場合、コードはタイヤ周方向に対し７０°〜９０°の角度で配列される。 Moreover, it has the carcass 7 (1 ply in FIG. 1) which consists of at least one carcass ply extended in a toroid between a pair of bead cores 2 (only one side is shown) embedded in the bead part 4. In FIG. 1, the carcass ply has a shape in which each side portion is folded around the pair of bead cores 2 and the rubber 3, but the present invention is not limited thereto. The ply constituting the carcass 7 is a cord rubber coating layer, and examples of the cord material include steel and organic fibers. In the case of a radial carcass, the cords are arranged at an angle of 70 ° to 90 ° with respect to the tire circumferential direction.

空気入りタイヤ１は、カーカス７のタイヤ径方向外側、コードをゴム被覆してなる少なくとも１層のベルト層８（図１では２層）を備える。コードとしては、スチールコードや有機繊維コードが例示できる。ベルト層８は、典型的にはコードのタイヤ赤道面に対する傾斜角度が互いに逆向きの２枚のベルトプライを貼り合わせた交錯ベルト層からなる。さらに図１では、ベルト層８のタイヤ径方向外側に、コードがタイヤ赤道面と略平行に配列された第１のベルト補強層９（キャップ層、図１では半部のみ図示）を備える。また、第１のベルト補強層９の両端部をそれぞれ覆うように配置した狭幅の第２のベルト補強層１０（レイヤー層、図１では片側のみ図示）を設けた、いわゆるキャップ＆レイヤー構造を有する。 The pneumatic tire 1 includes at least one belt layer 8 (two layers in FIG. 1) formed by rubber coating a cord on the outer side of the carcass 7 in the tire radial direction. Examples of the cord include a steel cord and an organic fiber cord. The belt layer 8 is typically composed of a crossing belt layer in which two belt plies whose inclination angles with respect to the tire equator plane are opposite to each other are bonded together. Further, in FIG. 1, a first belt reinforcing layer 9 (cap layer, only half of which is shown in FIG. 1) in which a cord is arranged substantially parallel to the tire equatorial plane is provided outside the belt layer 8 in the tire radial direction. Further, a so-called cap and layer structure provided with a narrow second belt reinforcing layer 10 (layer layer, only one side is shown in FIG. 1) arranged so as to cover both ends of the first belt reinforcing layer 9 respectively. Have.

次に、本発明の構成上の主な特徴であるタイヤの側周面の輪郭形状について図１及び図２を参照して説明する。空気入りタイヤ１は、適用リム１４に装着し所定空気圧を充填した無負荷状態におけるタイヤの装着姿勢にて、タイヤの側周面形状が、タイヤ幅方向断面で見て、タイヤ外方に向かって凸となる曲率を持つ第１の曲線部１１と、該第１の曲線部１１のタイヤ径方向内側に連なりタイヤ内方に向かって凸となる曲率を持つ第２の曲線部１２と、該第２の曲線部１２のタイヤ径方向内側に連なりタイヤ外方に向かって凸となる曲率を持つ第３の曲線部１３とを含む。そして、これら第１〜３の曲線部が以下の条件を満たすことが特徴である。 Next, the contour shape of the tire side peripheral surface, which is the main feature of the present invention, will be described with reference to FIGS. The pneumatic tire 1 is mounted on the applicable rim 14 and filled with a predetermined air pressure. When the tire is mounted in a no-load state, the side circumferential surface shape of the tire is viewed from the cross section in the tire width direction. A first curved portion 11 having a convex curvature, a second curved portion 12 having a curvature that is continuous to the inside of the tire radial direction of the first curved portion 11 and convex toward the inside of the tire; And a third curved portion 13 having a curvature that is continuous with the inner side in the tire radial direction of the second curved portion 12 and protrudes outwardly of the tire. And these 1st-3rd curve parts satisfy | fill the following conditions.

なお、本明細書において「所定空気圧」とは、下記規格に記載されている適用サイズにおける単輪の最大荷重（最大負荷能力）に対応する空気圧のことを意味する。また「所定負荷条件」とは、同規格に記載されている適用サイズにおける単輪の最大荷重（最大負荷能力）の荷重をかけることを意味する。「適用リム」とは、同規格に記載されている適用サイズにおける標準リム（または“Approved Rim”、“Recommended Rim”）のことである。かかる産業規格については、タイヤが生産又は使用される地域に有効な規格が定められている。例えば、アメリカ合衆国では、”The Tire and Rim Association Inc.のYear Book”であり、欧州では、”The European Tire and Rim Technical OrganizationのSTANDARDS MANUAL”であり、日本では日本自動車タイヤ協会の”JATMA Year Book”である。 In the present specification, the “predetermined air pressure” means an air pressure corresponding to the maximum load (maximum load capacity) of a single wheel in the applicable size described in the following standard. Further, the “predetermined load condition” means applying a load of the maximum load (maximum load capacity) of a single wheel in the application size described in the same standard. The “applied rim” is a standard rim (or “Approved Rim” or “Recommended Rim”) in the applicable size described in the standard. As for such industrial standards, standards that are effective in regions where tires are produced or used are defined. For example, “Year Book of The Tire and Rim Association Inc.” in the United States, “STANDARDS MANUAL of The European Tire and Rim Technical Organization” in Europe, and “JATMA Year Book” of the Japan Automobile Tire Association in Japan. It is.

（第１の曲線部）
まず、第１の曲線部１１について図２を参照して説明する。なお、図２においてはタイヤの側周面の輪郭形状をわかりやすくするため、適用リム１４を離して描いている。第１の曲線部１１は、適用リム１４のリムフランジ１４ａ断面の変曲点Ｑ（図１参照）からリム径ラインＲＬに下ろした垂線の足であるＰ点からリム径ラインに対して６０°〜７０°の範囲内にある所定角度θ１で延びる第１の線分１５上にあって、リム径ラインＲＬからタイヤ断面高さＳＨ（不図示）の３５％〜５０％の範囲内にある所定高さＳＷＨ１の位置にあるＡ点と、該Ａ点よりもタイヤ径方向内側の所定位置Ｂ点とを通り、所定曲率半径Ｒ１を有する第１の仮想円１１ａのうち、Ａ点と同じまたはＡ点よりもタイヤ径方向外側の所定位置Ｃ点から、第１の仮想円１１ａと第１の線分１５との交点であり、前記Ａ点よりもタイヤ径方向内側に位置する交点Ｄ点までの部分である。「タイヤ断面高さＳＨ」は、タイヤの外径とリム径の差の１／２と定義され、換言するとリム径ラインＲＬからタイヤ赤道位置にあるトレッド部６の表面までの距離である。また、「リム径ライン」とは、リム径を測定する位置をいう。 (First curve part)
First, the first curved portion 11 will be described with reference to FIG. In FIG. 2, the applied rim 14 is drawn away so that the contour shape of the side peripheral surface of the tire can be easily understood. The first curvilinear portion 11 is 60 ° from the point P, which is a perpendicular foot drawn from the inflection point Q (see FIG. 1) of the rim flange 14a section of the applicable rim 14 to the rim diameter line RL, with respect to the rim diameter line. On a first line segment 15 extending at a predetermined angle θ1 within a range of ˜70 °, and within a range of 35% to 50% of the tire cross-section height SH (not shown) from the rim diameter line RL. Of the first virtual circle 11a having a predetermined radius of curvature R1 passing through a point A at the height SWH1 and a predetermined position B on the inner side in the tire radial direction from the A point, the same as A or A From a predetermined position C point outside the point in the tire radial direction to an intersection point between the first virtual circle 11a and the first line segment 15 and an intersection point D located inside the tire radial direction from the point A Part. “Tire sectional height SH” is defined as ½ of the difference between the outer diameter of the tire and the rim diameter, in other words, the distance from the rim diameter line RL to the surface of the tread portion 6 at the tire equator position. Further, the “rim diameter line” refers to a position where the rim diameter is measured.

（第３の曲線部）
次に、第３の曲線部１３について説明する。第３の曲線部１３は、Ｐ点からリム径ラインＲＬに対してθ１よりも大きい７０°〜８０°の範囲内にある所定角度θ２で延びる第２の線分１６上にあって、リム径ラインＲＬからＳＨの４５％〜６０％の範囲内にある所定高さＳＷＨ２の位置にあるＥ点と、第１の仮想円１１ａと第２の線分１６との交点であるＦ点とを通り、前記曲率半径Ｒ１よりも大きい所定曲率半径Ｒ２を有する第２の仮想円１３ａ上の部分であって、前記Ｄ点よりタイヤ径方向内側に位置する第２の仮想円上の所定位置Ｇ点から前記Ｆ点までの部分である。 (Third curve part)
Next, the 3rd curve part 13 is demonstrated. The third curved line portion 13 is on a second line segment 16 extending at a predetermined angle θ2 within a range of 70 ° to 80 ° larger than θ1 with respect to the rim diameter line RL from the point P, and has a rim diameter. It passes through the point E at the position of the predetermined height SWH2 within the range of 45% to 60% of SH from the line RL, and the point F that is the intersection of the first virtual circle 11a and the second line segment 16. , A portion on the second virtual circle 13a having a predetermined radius of curvature R2 larger than the radius of curvature R1, and from a predetermined position G on the second virtual circle located on the inner side in the tire radial direction from the point D. This is the portion up to point F.

（第２の曲線部）
最後に、第１の曲線部１１と第３の曲線部１３とを繋ぐ第２の曲線部１２について説明する。第２の曲線部１２は、前記Ｄ点から前記Ｇ点までを３０ｍｍ以下の所定曲率半径Ｒ３（不図示）で結んだ曲線部である。ここで、線分１６上のＧ点は、第２の曲線部１２の曲率半径Ｒ３が決まれば、その曲率半径を有するように任意の位置にとることができる。 (Second curve part)
Finally, the second curved portion 12 connecting the first curved portion 11 and the third curved portion 13 will be described. The second curved portion 12 is a curved portion connecting the point D to the point G with a predetermined curvature radius R3 (not shown) of 30 mm or less. Here, if the curvature radius R3 of the 2nd curve part 12 is decided, G point on the line segment 16 can be taken in arbitrary positions so that it may have the curvature radius.

Ｂ点が、タイヤ装着姿勢で適用リム１４のリムフランジ１４ａと接触しているタイヤ径方向最外側位置である。 Point B is the outermost position in the tire radial direction in contact with the rim flange 14a of the applied rim 14 in the tire mounting posture.

そして、図１，２からも明らかな通り、隣接する第１および第２の曲線部同士は凹凸がタイヤ幅方向で互いに逆になっていることから、Ｄ点は角張った点となる。そこで、実際にはＤ点は変曲点となるように、Ｄ点の極近傍で丸みを帯びている。 As is clear from FIGS. 1 and 2, the first and second curved portions adjacent to each other have irregularities opposite to each other in the tire width direction, so that the point D is an angular point. Therefore, in reality, the D point is rounded in the vicinity of the D point so that it becomes an inflection point.

ここで、本発明がこのような構成を採用した技術的意義を作用・効果も含めて説明する。図２において仮に第１の曲線部１１がＣ点からＢ点まで連続していた場合、すなわち、Ｄ点からＢ点までのタイヤの側周面の輪郭形状が従来タイヤのように破線で示した第１の仮想円１１ａをとった場合は、図４，５ですでに述べたのと同じ問題が生じる。そこで、負荷転動時にリムフランジ１４ａと接触する可能性のあるタイヤのＢ点よりもタイヤ径方向外側にある側周面部分を、第２の曲線部１２と第３の曲線部１３とで区画した凹部で構成することを本発明者が着想した。図３は、空気入りタイヤ１の適用リム１４への装着状態を示す図１の部分拡大図である。図３は無負荷状態であるが、負荷転動時には、リムフランジ１４ａとくり返し接触しうる領域は、Ｂ点よりもタイヤ径方向外側になり、Ｆ点あるいは第３の曲線部１３の少なくとも一部分も接触しうる。その場合、図５の従来タイヤに比べて、負荷転動時にリムフランジ１４ａからの干渉、入力が少なくなる結果、空気入りタイヤ２０とリム２４とのフィット状態崩れにくく、リムずれが生じにくい。その結果、操縦安定性および乗り心地を損なうことがない。 Here, the technical significance in which the present invention employs such a configuration will be described, including the functions and effects. In FIG. 2, if the first curved portion 11 is continuous from the point C to the point B, that is, the contour shape of the side peripheral surface of the tire from the point D to the point B is indicated by a broken line as in the conventional tire. When the first virtual circle 11a is taken, the same problem as described above with reference to FIGS. Therefore, a side circumferential surface portion that is on the outer side in the tire radial direction from the point B of the tire that may come into contact with the rim flange 14 a during load rolling is partitioned by the second curved portion 12 and the third curved portion 13. The present inventor has conceived that it is constituted by a concave portion. FIG. 3 is a partially enlarged view of FIG. 1 showing a state where the pneumatic tire 1 is mounted on the application rim 14. Although FIG. 3 shows an unloaded state, the region where the rim flange 14a can repeatedly contact with the rim flange 14a at the time of load rolling is located outside the point B in the tire radial direction, and at least a part of the point F or the third curved portion 13 is also present. Can touch. In this case, as compared with the conventional tire of FIG. 5, the interference and input from the rim flange 14a during load rolling are reduced. As a result, the fitted state between the pneumatic tire 20 and the rim 24 is less likely to be lost, and rim displacement is less likely to occur. As a result, steering stability and riding comfort are not impaired.

ここで、本発明においては、θ２をθ１より大きくすることが重要となる。θ２＞θ１とすることによって、新たに第３の曲線部１３を規定することができ、負荷転動時にリムフランジ１４ａからの干渉、入力を少なくすることができるからである。 Here, in the present invention, it is important to make θ2 larger than θ1. This is because by setting θ2> θ1, the third curved portion 13 can be newly defined, and interference and input from the rim flange 14a can be reduced during load rolling.

また、Ｒ２をＲ１よりも大きくすることによって、第３の曲線部１３は第１の曲線部１１よりも立ち上がるので、負荷転動時にリムフランジ１４ａからの干渉、入力をより少なくすることができる。 Further, by making R2 larger than R1, the third curved portion 13 rises more than the first curved portion 11, so that interference and input from the rim flange 14a can be reduced during load rolling.

ここで、Ａ点を特定するにあたり、第１の線分１５がリム径ラインＲＬとなす角θ１を６０°〜７０°とし、リム径ラインＲＬからＡ点までの高さＳＷＨ１をタイヤ断面高さＳＨの３５％〜４５％としたのは、操縦安定性の確保と製造安定性の観点であるすなわち、θ１が６０°未満では、製造安定性の点で好ましくなく、７０°を超えると、操縦安定性の点で好ましくない。また、ＳＷＨ１がＳＨの３５％未満であると、製造安定性の点で好ましくなく、４５％を超えると、操縦安定性の点で好ましくない。 Here, in specifying the point A, the angle θ1 between the first line segment 15 and the rim diameter line RL is set to 60 ° to 70 °, and the height SWH1 from the rim diameter line RL to the point A is defined as the tire cross-section height. The reason why SH is set to 35% to 45% is from the viewpoint of ensuring steering stability and manufacturing stability. That is, when θ1 is less than 60 °, it is not preferable in terms of manufacturing stability. It is not preferable in terms of stability. Further, if SWH1 is less than 35% of SH, it is not preferable in terms of production stability, and if it exceeds 45%, it is not preferable in terms of steering stability.

また、Ｅ点を特定するにあたり、第２の線分１６がリム径ラインＲＬとなす角θ２を７０°〜８０°とし、リム径ラインＲＬからＥ点までの高さＳＷＨ２をタイヤ断面高さＳＨの４５％〜６０％としたのは、以下の理由である。すなわち、θ２が７０°未満では、θ１との差が小さくなりすぎて、負荷転動時にリムフランジ１４ａからの干渉、入力を少なくする作用が少なくなる点で好ましくなく、８０°を超えると、操縦安定性の点で好ましくない。また、ＳＷＨ１がＳＨの４５％未満であると、負荷転動時にリムフランジ１４ａからの干渉、入力を少なくする作用が少なくなる点で好ましくなく、６０％を超えると、操縦安定性の点で好ましくない。θ２とＳＷＨ２を定めてＥ点が特定されれば、Ｆ点の位置も特定される。ＢＦ間の距離は３〜５ｍｍ程度となることが好ましい。 In specifying the point E, the angle θ2 between the second line segment 16 and the rim diameter line RL is set to 70 ° to 80 °, and the height SWH2 from the rim diameter line RL to the point E is set to the tire cross-section height SH. The reason why the ratio is set to 45% to 60% is as follows. That is, if θ2 is less than 70 °, the difference from θ1 becomes too small, which is not preferable in that the effect of reducing interference and input from the rim flange 14a during load rolling is reduced. It is not preferable in terms of stability. Further, when SWH1 is less than 45% of SH, it is not preferable in terms of reducing the effect of reducing interference and input from the rim flange 14a during load rolling, and exceeding 60% is preferable in terms of steering stability. Absent. If the point E is specified by defining θ2 and SWH2, the position of the point F is also specified. The distance between BF is preferably about 3 to 5 mm.

また、第３の曲線部もタイヤ内方に凸にしてしまうと、リムとの均一な接地圧が保持できなくなる。そのため、第２の曲線部１２をタイヤ内方に向かって凸にし、第３の曲線部１３をタイヤ外方に向かって凸にした。 Further, if the third curved portion is also protruded inward of the tire, a uniform contact pressure with the rim cannot be maintained. Therefore, the second curved portion 12 is convex toward the inside of the tire, and the third curved portion 13 is convex toward the outside of the tire.

第２の曲線部の曲率半径Ｒ３を３０ｍｍ以下としたのは、３０ｍｍより大きくすると、負荷転動時にリムと接触する可能性が高くなるためである。
ここで、線分１６上のＧ点は、第２の曲線部１２の曲率半径Ｒ３が決まれば、第２の曲線部１２と第２の仮想円１３ａとの交点として特定される。Ｒ３を３０ｍｍ以下とすることにより、窪み量を確保できるのである。 The reason why the radius of curvature R3 of the second curved portion is set to 30 mm or less is that, when the radius of curvature is larger than 30 mm, there is a higher possibility of contact with the rim during load rolling.
Here, the point G on the line segment 16 is specified as the intersection of the second curved line portion 12 and the second virtual circle 13a if the curvature radius R3 of the second curved line portion 12 is determined. By setting R3 to 30 mm or less, the amount of depression can be secured.

第１の曲線部１１のうち最もタイヤ径方向外側であるＣ点の位置は、Ａ点と同じ位置、またはＡ点よりもタイヤ径方向外側であれば特に限定されない。 The position of the point C that is the outermost side in the tire radial direction in the first curved portion 11 is not particularly limited as long as it is the same position as the point A or the outer side in the tire radial direction than the point A.

図２に示すように、第１の曲線部１１の曲率中心Ｏ１が、Ａ点を通りリム径ラインＲＬに平行な線１７上にあり、第３の曲線部１３の曲率中心Ｏ２が、Ｅ点を通りリム径ラインＲＬに平行な線１８上にあることが、本発明の効果をよりえる観点から好ましい。この場合、Ａ点はタイヤ幅方向の最大幅位置となる。 As shown in FIG. 2, the center of curvature O1 of the first curved portion 11 is on the line 17 passing through the point A and parallel to the rim diameter line RL, and the center of curvature O2 of the third curved portion 13 is the point E. From the viewpoint of obtaining the effects of the present invention, it is preferable to be on the line 18 that passes through the rim diameter line RL. In this case, the point A is the maximum width position in the tire width direction.

Ｒ１が２０〜１００ｍｍであり、Ｒ２が１００〜２５０ｍｍであることが好ましい。Ｒ２が１００ｍｍ未満の場合、リムフランジとの干渉が生じるおそれがあり、Ｒ２が２５０ｍｍ超えの場合、均一なタイヤ／リム接地圧の確保が困難となるおそれがある。 It is preferable that R1 is 20 to 100 mm and R2 is 100 to 250 mm. If R2 is less than 100 mm, interference with the rim flange may occur, and if R2 exceeds 250 mm, it may be difficult to ensure uniform tire / rim contact pressure.

また、本実施形態の空気入りタイヤ１は、タイヤ断面高さＳＨが７０〜１５０ｍｍの範囲内で、偏平率は３０〜５５％の範囲内であることが、Ｒ１をより小さくする観点から好ましい。 Further, in the pneumatic tire 1 of the present embodiment, it is preferable from the viewpoint of making R1 smaller that the tire cross-section height SH is in the range of 70 to 150 mm and the flatness is in the range of 30 to 55%.

本実施形態では、図１に示した内部構造で説明したが、本発明の特徴はサイドウォール形状にあり、タイヤの内部構造はこれに限られない。また、本実施形態の空気入りタイヤ１は乗用車用タイヤをはじめ、いずれの用途のタイヤにも用いることができる。 In the present embodiment, the internal structure shown in FIG. 1 has been described, but the feature of the present invention is the sidewall shape, and the internal structure of the tire is not limited to this. Moreover, the pneumatic tire 1 of this embodiment can be used for tires of any application including a tire for a passenger car.

次に、本発明の効果をさらに明確にするために、以下の実施例、比較例、および従来例にかかる空気入りタイヤを用いて行った比較評価について説明する。ＪＡＴＭＡ規格に定める適用リムに装着した、表１に記載の実施例タイヤおよび比較例タイヤを一般車両に４輪とも装着し、２名が乗車して実車走行試験を行った。具体的には、欧州市場路面を時速４０〜１００ｋｍで走行した。各タイヤのサイズは２４５／４５Ｒ１８とし、内圧２２０ｋＰａ、荷重２名乗車相当とした。リムフランジ形状はいずれも８Ｊ、フランジ高さはいずれも１７．３ｍｍとした。 Next, in order to further clarify the effects of the present invention, comparative evaluations performed using pneumatic tires according to the following examples, comparative examples, and conventional examples will be described. Example tires and comparative tires shown in Table 1 mounted on an applicable rim defined in the JATMA standard were mounted on a general vehicle with all four wheels, and two people got on to perform an actual vehicle running test. Specifically, I drove on the European market at a speed of 40-100 km / h. Each tire had a size of 245 / 45R18, an internal pressure of 220 kPa, and a load equivalent to two passengers. The rim flange shape was 8J in all cases, and the flange height was 17.3 mm in all cases.

走行開始時と４０ｋｍ走行後について、操縦安定性評価と乗り心地評価を専門のドライバー２名で行い、２名のフィーリング評点（１０点満点）の平均を求めた。なお、評価基準としては７点以上であれば合格点であり、それ以下では性能不足と感じられる。その結果を、表１にあわせて示す。 At the start of running and after running 40km, steering stability evaluation and riding comfort evaluation were performed by two specialized drivers, and the average of the two feeling scores (up to 10 points) was obtained. In addition, as an evaluation standard, if it is 7 points or more, it is a passing score, and if it is less than that, it is felt that performance is insufficient. The results are also shown in Table 1.

表１に示すとおり、本発明の条件を満たす実施例は、本発明の条件を満足しない従来例および比較例に比べて、操縦安定性と乗り心地が良く、また、走行を続けてもこれらの性能の低下がないことが確かめられた。 As shown in Table 1, the examples that satisfy the conditions of the present invention have better handling stability and ride comfort than the conventional examples and comparative examples that do not satisfy the conditions of the present invention. It was confirmed that there was no performance degradation.

本発明によれば、負荷転動時におけるリムずれを有効に防止して、リムとの好適なフィット状態を保つことが可能で、操縦安定性および乗り心地を損なわない新規な空気入りタイヤを提供することができる。 According to the present invention, a novel pneumatic tire that can effectively prevent rim deviation during load rolling and maintain a suitable fit state with a rim and does not impair driving stability and riding comfort is provided. can do.

１空気入りタイヤ１１第１の曲線部１１ａ第１の仮想円
１２第２の曲線部１３第３の曲線部１３ａ第２の仮想円
１４適用リム１４ａリムフランジ１５第１の線分
１６第２の線分１７Ａ点を通りリム径ラインに平行な線
１８Ｅ点を通りリム径ラインに平行な線ＲＬリム径ライン
Ｒ１第１の曲線部の曲率半径Ｒ２第３の曲線部の曲率半径
Ｒ３第２の曲線部の曲率半径（図示せず）Ｏ１第１の曲線部の曲率中心
Ｏ２第３の曲線部の曲率中心
DESCRIPTION OF SYMBOLS 1 Pneumatic tire 11 1st curve part 11a 1st virtual circle
12 Second curve portion 13 Third curve portion 13a Second virtual circle 14 Applicable rim 14a Rim flange 15 First line segment 16 Second line segment 17 Line passing through point A and parallel to the rim diameter line 18 E Line that passes through the point and is parallel to the rim diameter line RL Rim diameter line
R1 radius of curvature of the first curved portion R2 radius of curvature of the third curved portion R3 radius of curvature of the second curved portion (not shown) O1 center of curvature of the first curved portion O2 center of curvature of the third curved portion

Claims

適用リムに装着し所定空気圧を充填した無負荷状態におけるタイヤの装着姿勢にて、タイヤの側周面形状がタイヤ幅方向断面で見て、
タイヤ外方に向かって凸となる曲率を持つ第１の曲線部と、
該第１の曲線部のタイヤ径方向内側に連なりタイヤ内方に向かって凸となる曲率を持つ第２の曲線部と、
該第２の曲線部のタイヤ径方向内側に連なりタイヤ外方に向かって凸となる曲率を持つ第３の曲線部とを含み、
前記第１〜３の曲線部が下記に示す条件ａ〜ｅを満たすことを特徴とする空気入りタイヤ。
＜記＞
ａ．前記第１の曲線部は、
前記適用リムのリムフランジ断面の変曲点からリム径ラインに下ろした垂線の足であるＰ点からリム径ラインに対して６０°〜７０°の範囲内にある所定角度θ１で延びる第１の線分上にあって、リム径ラインからタイヤ断面高さＳＨの３５％〜５０％の範囲内にある所定高さＳＷＨ１の位置にあるＡ点と、該Ａ点よりもタイヤ径方向内側の所定位置Ｂ点とを通り、所定曲率半径Ｒ１を有する第１の仮想円のうち、前記Ａ点と同じまたは前記Ａ点よりもタイヤ径方向外側の所定位置Ｃ点から、該第１の仮想円と前記第１の線分との交点であり、前記Ａ点よりもタイヤ径方向内側に位置する交点Ｄ点までの部分である。
ｂ．前記第３の曲線部は、
前記Ｐ点からリム径ラインに対して前記θ１よりも大きい７０°〜８０°の範囲内にある所定角度θ２で延びる第２の線分上にあって、リム径ラインから前記ＳＨの４５％〜６０％の範囲内にある所定高さＳＷＨ２の位置にあるＥ点と、前記第１の仮想円と前記第２の線分との交点であるＦ点とを通り、前記曲率半径Ｒ１よりも大きい所定曲率半径Ｒ２を有する第２の仮想円上の部分であって、前記Ｄ点よりタイヤ径方向内側に位置する第２の仮想円上の所定位置Ｇ点から前記Ｆ点までの部分である。
ｃ．前記第２の曲線部は、前記Ｄ点から前記Ｇ点までを３０ｍｍ以下の所定曲率半径Ｒ３で結んだ曲線部である。
ｄ．前記Ｂ点が、前記タイヤ装着姿勢で適用リムのリムフランジと接触しているタイヤ径方向最外側位置である。
ｅ．前記ａ〜ｃに関わらず、前記Ｄ点が変曲点となる。 In the mounting posture of the tire in a no-load state that is mounted on the applicable rim and filled with a predetermined air pressure, the side circumferential surface shape of the tire is seen in the tire width direction cross section,
A first curved portion having a curvature convex toward the outside of the tire;
A second curved portion having a curvature that is continuous with the inside of the first curved portion in the tire radial direction and is convex toward the inside of the tire;
A third curve portion having a curvature that is continuous to the inside in the tire radial direction of the second curve portion and is convex toward the outside of the tire,
The pneumatic tire characterized by said 1st-3rd curve part satisfy | filling conditions ae shown below.
<Note>
a. The first curved portion is
The first rim extending at a predetermined angle θ1 within a range of 60 ° to 70 ° with respect to the rim diameter line from point P, which is a foot of a perpendicular line drawn from the inflection point of the rim flange section of the applied rim to the rim diameter line. A point on the line segment and located at a predetermined height SWH1 within a range of 35% to 50% of the tire cross-section height SH from the rim diameter line, and a predetermined point on the inner side in the tire radial direction from the point A Among the first virtual circles that pass through the point B and have a predetermined radius of curvature R1, the first virtual circle is the same as the point A or from the predetermined position C point outside the point A in the tire radial direction. It is an intersection with the first line segment, and is a portion up to an intersection point D located on the inner side in the tire radial direction from the point A.
b. The third curved portion is
It is on a second line segment extending at a predetermined angle θ2 within a range of 70 ° to 80 ° larger than θ1 with respect to the rim diameter line from the point P, and 45% to SH of the SH from the rim diameter line. It passes through the point E at the position of the predetermined height SWH2 within the range of 60% and the point F that is the intersection of the first virtual circle and the second line segment, and is larger than the curvature radius R1. A portion on a second imaginary circle having a predetermined radius of curvature R2, which is a portion from a predetermined position G on the second imaginary circle located on the inner side in the tire radial direction from the point D to the point F.
c. The second curved portion is a curved portion connecting the point D to the point G with a predetermined radius of curvature R3 of 30 mm or less.
d. The point B is the outermost position in the tire radial direction in contact with the rim flange of the application rim in the tire mounting posture.
e. Regardless of a to c, the point D is an inflection point.

前記第１の曲線部の曲率中心が、Ａ点を通りリム径ラインに平行な線上にあり、
前記第３の曲線部の曲率中心が、Ｅ点を通りリム径ラインに平行な線上にある請求項１に記載の空気入りタイヤ。 The center of curvature of the first curved portion is on a line passing through point A and parallel to the rim diameter line;
2. The pneumatic tire according to claim 1, wherein a center of curvature of the third curved portion is on a line passing through point E and parallel to the rim diameter line.

前記Ｒ１が２０〜１００ｍｍであり、前記Ｒ２が１００〜２５０ｍｍである請求項１または２に記載の空気入りタイヤ。 The pneumatic tire according to claim 1 or 2, wherein the R1 is 20 to 100 mm, and the R2 is 100 to 250 mm.

前記第３の曲線部は、負荷転動時には適用リムのリムフランジとくり返し接触する部分である請求項１〜３のいずれか１項に記載の空気入りタイヤ。
The pneumatic tire according to any one of claims 1 to 3, wherein the third curved portion is a portion that repeatedly comes into contact with a rim flange of an applicable rim during load rolling.