JP2004131002A

JP2004131002A - Wheel for railway

Info

Publication number: JP2004131002A
Application number: JP2002299235A
Authority: JP
Inventors: Takanori Kato; 加藤　孝憲; Mitsusachi Yamamoto; 山本　三幸; Yoshinari Yamamura; 山村　佳成
Original assignee: Sumitomo Metal Industries Ltd
Current assignee: Nippon Steel Corp
Priority date: 2002-10-11
Filing date: 2002-10-11
Publication date: 2004-04-30

Abstract

<P>PROBLEM TO BE SOLVED: To provide a wheel for railway capable of maintaining safety factor equipment to a conventional wheel for railway even if thickness of plate is reduced. <P>SOLUTION: In a case of an A-type wheel 1A in which a rim part 15 is eccentric to an outer wheel side in relation to a boss part 11, an angle α between a normal h in relation to an axial center Z and a tangent L of an inner wheel side curved line ab of two curved lines ab, cd defining a section shape in a radial direction of a boss part fillet 12, a plate part 13 and a rim part fillet 14 is measured, a point on the inner wheel side curved line ab which provides the maximum value α<SB>max</SB>is determined at a position in a boss 11 side of a point on which the inner wheel side curved line ab and an auxiliary line segment formed at a position of an equal distance from a boss side line segment ab and a rim side line segment cd cross. <P>COPYRIGHT: (C)2004,JPO

Description

【０００１】
【発明の属する技術分野】
内側から外側にかけてボス部、ボス部フィレット、板部、リム部フィレット、リム部及びフランジからなり、前記リム部が前記ボス部に対して、外輪側または内輪側に偏心しているＡ形またはＢ形の鉄道用車輪に関し、特にボス部フィレットとリム部フィレットとの間の板部の形状を最適化した鉄道用車輪に関する。
【０００２】
【従来の技術】
鉄道車両の高速化、省エネルギーの観点から鉄道用車輪（以下、車輪という）の軽量化が望まれている。車輪の軽量化は、板部の板厚を減少させることによって可能となるが、板厚の減少により耐割損性が低下する。従って、耐割損性を維持しつつ車輪の軽量化を図ることが必要となる。
【０００３】
従来の鉄道用車輪は、例えば日本工業規格ＪＩＳ　Ｅ５４０２−１９８９等に従い設計されている。かかる規格においては、鉄道用車輪はＡ形、Ｂ形、及びＣ形の３種が規定されている。図５はＡ形車輪の径方向の断面形状を示す断面図、図６はＢ形車輪の径方向の断面形状を示す断面図、図７はＣ形車輪の径方向の断面形状を示す断面図である。図示しない車軸が嵌挿されるボス部１１Ａから、順に外側へかけてボス部フィレット１２Ａ、板部１３Ａ、リム部フィレット１４Ａ、リム部１５Ａ、及び車輪内輪側に突設されるフランジ１６Ａから、Ａ形車輪１０Ａが形成される。Ａ形車輪１０Ａはリム部１５Ａがボス部１１Ａに対して外輪側に偏心している形状と定義され、また、ＪＩＳ規格５４０２−１９８９によれば、各部位の長さは下記の表１に示す如く規定されている。
【０００４】
【表１】

【０００５】
図６に示すように、Ｂ形車輪１０Ｂも同様に、図示しない車軸が嵌挿されるボス部１１Ｂから、順に外側へかけてボス部フィレット１２Ｂ、板部１３Ｂ、リム部フィレット１４Ｂ、リム部１５Ｂ、及び車輪内輪側に突設されるフランジ１６Ｂから、Ｂ形車輪１０Ｂが形成される。Ｂ形車輪１０Ｂは、Ａ形車輪１０Ａとは逆に、リム部１５Ｂがボス部１１Ｂに対して内輪側に偏心している形状と定義され、また、ＪＩＳ規格５４０２−１９８９によれば、各部位の長さは下記の表２に示す如く規定されている。
【０００６】
【表２】

【０００７】
新幹線等に用いられるＣ形車輪１０Ｃの径方向の断面形状も、図７に示すように他の車輪と同じく図示しない車軸が嵌挿されるボス部１１Ｃから、順に外側へかけてボス部フィレット１２Ｃ、板部１３Ｃ、リム部フィレット１４Ｃ、リム部１５Ｃ、及び車輪内輪側に突設されるフランジ１６Ｃから、Ｃ形車輪１０Ｃが形成される。Ｃ形車輪１０Ｃは、Ａ形車輪１０Ａ及びＢ形車輪１０Ｂとは異なり、リム部１５Ｃがボス部１１Ｃに対して内輪側及び外輪側いずれにも偏心していない形状と定義され、また、ＪＩＳ規格５４０２−１９８９によれば、各部位の長さは下記の表３に示す如く規定されている。
【０００８】
【表３】

【０００９】
【特許文献１】
特開平１０−２９４０１号公報
【００１０】
【発明が解決しようとする課題】
しかしながら、例えば、表１に示すように従来の車輪は板部の板厚がリム側でｔ_１＝１８ｍｍ、ボス側でｔ_２＝２２ｍｍ〜２６ｍｍと厚いため、車輪の軽量化による鉄道の高速化及び省エネルギー化を達成することは困難であった。また、軽量化を図るべく、板厚を薄くした場合、耐割損性が増加し安全率が低下するという問題があった。レールからの反力により発生する応力（機械的応力）が増加した場合、耐割損性が増加し、安全率が低下する。本願出願人は安全率を維持または向上させつつ、板部の板厚を薄くし、軽量化を図ることが可能な車輪を開発すべく鋭意研究を重ねた結果、Ａ形車輪の場合、板部の径方向の断面形状を規定する２つの曲線のうち、内輪側の曲線形状を特定の形状とすることにより、板部の板厚を薄くしつつも、安全率を向上することが可能であることを知見した。
【００１１】
一方、Ｂ形車輪の場合、板部の径方向の断面形状を規定する２つの曲線のうち、外輪側の曲線形状を特定の形状とすることにより、Ａ形車輪と同様に板部の板厚を薄くしつつも、安全率を向上することが可能であることをも知見した。
【００１２】
本発明は斯かる知見に鑑みてなされたものであり、その目的とするところは、板部の径方向の断面形状を規定する２つの曲線のうち、Ａ形車輪の場合は、内輪側の曲線形状を特定の形状とすることにより、またＢ形車輪の場合は、外輪側の曲線形状を特定の形状とすることにより、板厚を薄くした場合であっても、従来と同等の安全率を維持することが可能な鉄道用車輪を提供することにある。
【００１３】
【課題を解決するための手段】
第１発明に係る鉄道用車輪は、内側から外側にかけてボス部、ボス部フィレット、板部、リム部フィレット、リム部、及び、フランジを有し、前記リム部が前記ボス部に対して外輪側に偏心している鉄道用車輪において、前記ボス部フィレット、板部及びリム部フィレットの径方向の断面形状を規定する２つの曲線のうち、内輪側の曲線の接線と、前記ボス部に挿嵌される車軸の軸心に対する法線とのなす角の最大値をとる前記内輪側板部の曲線上の点が、前記２つの曲線と前記ボス部との交点により規定されるボス側線分、及び、前記２つの曲線と前記リム部との交点により規定されるリム側線分から等距離の位置に形成される補助線分が前記内輪側の曲線と交差する点よりもボス側に位置することを特徴とする。
【００１４】
第２発明に係る鉄道用車輪は、内側から外側にかけてボス部、ボス部フィレット、板部、リム部フィレット、リム部、及び、フランジを有し、前記リム部が前記ボス部に対して内輪側に偏心している鉄道用車輪において、前記ボス部フィレット、板部及びリム部フィレットの径方向の断面形状を規定する２つの曲線のうち、外輪側の曲線の接線と、前記ボス部に挿嵌される車軸の軸心に対する法線とのなす角の最大値をとる前記外輪側板部の曲線上の点が、前記２つの曲線と前記ボス部との交点により規定されるボス側線分、及び、前記２つの曲線と前記リム部との交点により規定されるリム側線分から等距離の位置に形成される補助線分が前記外輪側の曲線と交差する点よりもボス側に位置することを特徴とする。
【００１５】
第３発明に係る鉄道用車輪は、内側から外側にかけてボス部、ボス部フィレット、板部、リム部フィレット、リム部、及び、フランジを有し、前記リム部が前記ボス部に対して外輪側に偏心している鉄道用車輪において、前記ボス部フィレット、板部及びリム部フィレットの径方向の断面形状を規定する２つの曲線のうち、内輪側の曲線の接線と、前記ボス部に挿嵌される車軸の軸心に対する法線とのなす角の最大値をとる前記内輪側板部の曲線上の点が、前記２つの曲線と前記ボス部との交点により規定されるボス側線分からと、前記２つの曲線と前記リム部との交点により規定されるリム側線分からとの距離比が０．５５対０．４５の位置に形成される補助線分が前記内輪側の曲線と交差する点よりもボス側に位置することを特徴とする。
【００１６】
第４発明にかかる鉄道用車輪は、内側から外側にかけてボス部、ボス部フィレット、板部、リム部フィレット、リム部、及び、フランジを有し、前記リム部が前記ボス部に対して内輪側に偏心している鉄道用車輪において、前記ボス部フィレット、板部及びリム部フィレットの径方向の断面形状を規定する２つの曲線のうち、外輪側の曲線の接線と、前記ボス部に挿嵌される車軸の軸心に対する法線とのなす角の最大値をとる前記外輪側板部の曲線上の点が、前記２つの曲線と前記ボス部との交点により規定されるボス側線分からと、前記２つの曲線と前記リム部との交点により規定されるリム側線分からとの距離比が０．５５対０．４５の位置に形成される補助線分が前記外輪側の曲線と交差する点よりもボス側に位置することを特徴とする。
【００１７】
第１及び第３発明にあっては、リム部がボス部に対して、外輪側に偏心しているＡ形車輪の場合、ボス部フィレット、板部及びリム部フィレットの径方向の断面形状を規定する２つの曲線のうち、内輪側の曲線について着目する。曲線は、２つの曲線とボス部との交点により規定されるボス側線分から、２つの曲線とリム部との交点により規定されるリム側線分に至る。内輪側の曲線の接線と、ボス部に挿嵌される車軸の軸心に対する法線とのなす角を計測し、その最大値をとる内輪側板部の曲線上の点が、ボス側線分及びリム側線分から等距離の位置に形成される補助線分が内輪側の曲線と交差する点よりもボス側に位置するよう決定する。また、安全率を従来の車輪以上とするためには、後述する実験により、内輪側の曲線の接線と、ボス側線分の法線とのなす角の最大値をとる内輪側板部の曲線上の点が、ボス側線分からと、リム側線分からとの距離比が０．５５対０．４５の位置に形成される補助線分が内輪側の曲線と交差する点よりもボス側に位置するようにすれば良い。鉄道用車輪の板部形状をかかる構成とすることで、安全率のさらなる向上、ひいては板部の板厚を薄くし、軽量化を図りつつも従来と同様またはそれ以上の安全率を確保することが可能となる。
【００１８】
第２及び第４発明にあっては、リム部がボス部に対して、内輪側に偏心しているＢ形車輪の場合、ボス部フィレット、板部及びリム部フィレットの径方向の断面形状を規定する２つの曲線のうち、外輪側の曲線について着目する。同様に、外輪側の曲線の接線と、ボス部に挿嵌される車軸の軸心に対する法線とのなす角を計測し、その最大値をとる外輪側の曲線上の点が、ボス側線分及びリム側線分から等距離の位置に形成される補助線分が外輪側の曲線と交差する点よりもボス側に位置するよう決定する。または、安全率を従来の車輪以上とするためには、後述する実験により、外輪側の曲線の接線と、ボス側線分の法線とのなす角の最大値をとる外輪側板部の曲線上の点が、ボス側線分からと、リム側線分からとの距離比が０．５５対０．４５の位置に形成される補助線分が外輪側の曲線と交差する点よりもボス側に位置すれば良い。このように、リム部の偏心方向と逆方向の板部曲線の形状をかかる形状とすることで、板部の板厚を薄くし、軽量化を図りつつも従来と同様またはそれ以上の安全率を確保でき、さらに鉄道車両の高速化及び省エネルギー化を図ることが可能となる。
【００１９】
【発明の実施の形態】
以下本発明を実施の形態を示す図面に基づいて詳述する。
実施の形態１
図１はＡ形車輪１Ａ（場合により、車輪１で代表する）の径方向の断面形状を示す断面図である。Ａ形車輪１Ａは、内側から外側にかけてボス部１１，ボス部フィレット１２，板部１３，リム部フィレット１４，リム部１５，及びフランジ１６からなり、リム部１５がボス部１１に対して外輪側に偏心している。図示しない車軸が径方向に対して垂直に嵌挿されるボス部１１には、板部１３に至るボス部フィレット１２が形成されており、車輪厚はボス部フィレット１２を経由して、ボス部１１のボス高さＨから板部１３の板厚ｔ_２（ボス側）にまで変化する。なお、各部位の長さは表１に示すとおりである。
【００２０】
板部１３の一端は上述したボス部フィレット１２と接合しており、一方板部１３の他端はリム部フィレット１４と接合している。板部１３の径方向の断面形状は曲線ｓｔ、及び曲線ｕｗ、並びに曲線ｓｔ・曲線ｕｗとボス部フィレット１２とのそれぞれの交点ｓ、ｕにより規定される線分ｓｕ、及び、曲線ｓｔ・曲線ｕｗとリム部フィレット１４とのそれぞれの交点ｔ、ｗにより規定される線分ｔｗにより構成される。また、ボス部フィレット、板部及びリム部フィレットの径方向の断面形状を規定する２つの曲線は図１に示すように曲線ａｂ及び曲線ｃｄからなる。点ａは内輪側の曲線ａｂとボス部１１との交点であり、点ｃは外輪側の曲線ｃｄとボス部１１との交点である。以下では、線分ａｃをボス側線分という。同様に、点ｂは内輪側の曲線ａｂとリム部１５との交点であり、点ｄは外輪側の曲線ｃｄとリム部１５との交点である。以下では、線分ｂｄをリム側線分という。板部１３はリム部フィレット１４を介してリム部１５に接合されており、車輪厚はリム部フィレット１４を経由している間に板部１３の板厚ｔ_１（リム側）からリム幅Ｂにまで拡大する。また、リム部１５の内輪側先端にはフランジが突設されている。
【００２１】
Ａ形車輪１Ａにおいては、ボス部フィレット１２，板部１３及びリム部フィレット１４の断面形状を規定する２つの曲線ａｂ及び曲線ｃｄのうち、内輪側の曲線ａｂ、特に曲線ｓｔについて着目する。曲線ａｂ上の任意の点における接線Ｌと、ボス部に挿嵌される図示しない車軸の軸心Ｚに対する法線ｈとのなす角をαと定義する。本発明に係る車輪は、好ましくはαの最大角α_ｍａｘをとる内輪側板部の曲線ｓｔ上の点が、ボス側線分ａｃ及びリム側線分ｂｄから等距離の位置に形成され、ボス側線分ａｃ及びリム側線分ｂｄに平行な補助線分が、内輪側の曲線ａｂと交差する点ｅよりもボス側に位置するようにすれば良い。つまり、点ｓから補助線分と曲線ａｂとの交点である点ｅとの間のいずれかの位置に、最大角α_ｍａｘが形成されるよう板部１３の形状を設計する。若しくは、αの最大角α_ｍａｘをとる内輪側板部の曲線ｓｔ上の点が、ボス側線分ａｃからと、リム側線分ｂｄからとの距離比が０．５５対０．４５となる位置に形成され、ボス側線分ａｃ及びリム側線分ｂｄに平行な補助線分が、内輪側の曲線ａｂと交差する点ｅ’よりもボス側に位置するようにすれば良い。つまり、点ｓから補助線分と曲線ａｂとの交点である点ｅ’との間のいずれかの位置に、最大角α_ｍａｘが形成されるよう板部１３の形状を設計する。すなわち、外輪側に偏心しているＡ形車輪１Ａにおいては、対向する内輪側の曲線ｓｔのうち、ボス部１１側の接線Ｌと法線ｈとのなす角度αが最大となるよう、板部１３を設計することで、安全率を向上させることが可能となる。
【００２２】
図２はＢ形車輪１Ｂの径方向の断面形状を示す断面図である。Ｂ形車輪１Ｂも同様に、内側から外側にかけてボス部１１，ボス部フィレット１２，板部１３，リム部フィレット１４，リム部１５，及びフランジ１６からなり、リム部１５がボス部１１に対して内輪側に偏心している。
【００２３】
Ｂ形車輪１Ｂにおいては、ボス部フィレット１２，板部１３、及びリム部フィレット１４の断面形状を規定する２つの曲線ａｂ及び曲線ｃｄのうち、外輪側の曲線ｃｄ、特に曲線ｕｗについて着目する。曲線ｃｄ上の任意の点における接線Ｌと、軸心Ｚに対する法線ｈとのなす角をαと定義する。本発明に係る車輪は、好ましくはαの最大角α_ｍａｘをとる外輪側板部の曲線ｕｗ上の点が、ボス側線分ａｃ及びリム側線分ｂｄから等距離の位置に形成され、ボス側線分ａｃ及びリム側線分ｂｄに平行な補助線分が、外輪側の曲線ｃｄと交差する点ｆよりもボス側に位置するようにすれば良い。つまり、点ｕから補助線分と曲線ｃｄとの交点である点ｆとの間のいずれかの位置に、最大角α_ｍａｘが形成されるよう板部１３の形状を設計する。若しくは、αの最大角α_ｍａｘをとる外部側板部の曲線ｃｄ上の点が、ボス側線分ａｃからと、リム側線分ｂｄからとの距離比が０．５５対０．４５となる位置に形成され、ボス側線分ａｃ及びリム側線分ｂｄに平行な補助線分が、外輪側の曲線ｃｄと交差する点ｆ’よりもボス側に位置するようにすれば良い。つまり、点ｓから補助線分と曲線ｃｄとの交点である点ｆ’との間のいずれかの位置に、最大角α_ｍａｘが形成されるよう板部１３の形状を設計する。すなわち、内輪側に偏心しているＢ形車輪１Ｂにおいては、対向する外輪側の曲線ｕｗのうち、ボス部１１側の接線Ｌと法線ｈとのなす角度αが最大となるよう、板部１３を設計することで、安全率を向上させることが可能となる。
【００２４】
続いて、最大角α_ｍａｘをとる曲線上の位置を変化させて安全率がどのように変化するか実験を行った。なお、実験に当たってはＡ形車輪１Ａのうち表１に示すＡ８６Ｅを用い、板部１３の形状をそれぞれ変化させた車輪１を対象にＦＥＭ（Ｆｉｎｉｔｅ　Ｅｌｅｍｅｎｔ　Ｍｅｔｈｏｄ）解析を実施し、垂直圧及び横圧が負荷された場合の板部１３の発生応力と、垂直圧及び背圧が負荷された場合の発生応力を求め、各板部形状の耐割損性（安全率）について評価した。
【００２５】
なお以下に、垂直圧、横圧、及び背圧について説明しておく。図３は機械的応力の概念を説明する模式図である。機械的応力には図３（ａ）及び（ｂ）に示すように、垂直圧Ｐ_１、横圧Ｐ_２、及び背圧Ｐ_３が存在する。直線通過時においては、輪重により、リム部１５とレールＲとの接合面である車輪踏面ＱにはレールＲから垂直圧Ｐ_１が負荷される。曲線通過時においては、レールＲからフランジ１６に軌道内側から横圧Ｐ_２が負荷される。さらに、脱線防止用のガイドレールＰ又は図示しないポイントにより、フランジ１６に軌道外側から背圧Ｐ_３が負荷される。
【００２６】
図４は最大角α_ｍａｘをとる点の位置を変化させた場合の、当該車輪の安全率の推移を示す特性図ある。縦軸は安全率を示し、従来の車輪の安全率を１．０として評価している。横軸は補助線分の位置を示し、０をボス側線分ａｃと同じ位置、０．５をボス側線分及びリム側線分ｂｄから等距離の位置、１をリム側線分ｂｄと同じ位置としている。ここで、曲線ａｂ上の内曲線ｓｔ上の点における接線Ｌと法線ｈとがなす角αが最大値α_ｍａｘとなるとなる点を、位置を変えつつその各車輪における最小の安全率を車輪板部全体のＦＥＭ解析により求めた。解析にあっては試料１乃至５を用意した。試料１は従来の車輪であり、試料１及び２を除く試料３乃至５は本発明に係るＡ形車輪１Ａである。なお、各試料の最大角α_ｍａｘは、α_ｍａｘ１＝３９．９°（試料１）、α_ｍａｘ２＝４０．７°（試料２）、α_ｍａｘ３＝３３．４°（試料３）、α_ｍａｘ４＝３５．５°（試料４）、α_ｍａｘ５＝３６．０°（試料５）とした。
【００２７】
解析した結果、試料３乃至５に示すように０から０．５５までの間で、最大値α_ｍａｘをとる場合、安全率が高いことが理解できる。特に０．５５から０．５にかけて安全率の増加傾向が強まり、また０．５以下ではボスの内径、輪重等の諸条件が変わった場合でも高い安全率を確保できることが確認できた。一方で、試料２の如く０．５５を超える場合、従来の試料１に係る車輪と安全率はそれほど相違しないことが理解できる。このように最大値α_ｍａｘをとる点を特定の位置（点ｓ〜点ｅまたは点ｅ’）に決定することで、安全率の向上を図ることが可能となる。なお、Ｂ形車輪についても同様の結果が得られたので詳細な説明は省略する。また、上述した試料１乃至５は全て板部１３の板厚ｔ_１（リム側）を１８ｍｍ、板厚ｔ_２（ボス側）を２２ｍｍとして、安全率の変化を検討したが、安全率が１．０以上となるように板厚を適宜変化させるようにしても良い。この場合、リム外径Ｄに対して、板部１３の板厚が１．２％〜２．４％の範囲内にある場合、安全率１．０以上となることが確認できた。例えば、リム外径Ｄが８６０ｍｍの車輪の場合、板厚は１０．３２ｍｍ〜２０．６４ｍｍの範囲内であれば、安全率１．０以上を確保できる。これにより、安全率を確保しつつも、板部１３の薄型化を図ることができる。
【００２８】
【発明の効果】
以上詳述した如く、第１及び第３発明にあっては、リム部がボス部に対して、外輪側に偏心しているＡ形車輪の場合、ボス部フィレット、板部及びリム部フィレットの径方向の断面形状を規定する２つの曲線のうち、内輪側の曲線の接線と、ボス側線分の法線とのなす角を計測し、その最大値をとる内輪側板部の曲線上の点が、ボス側線分及びリム側線分から等距離の位置に形成される補助線分が内輪側の曲線と交差する点よりもボス側に位置するように設計する。または、ボス側線分からと、リム側線分からとの距離比が０．５５対０．４５の位置に形成される補助線分が内輪側の曲線と交差する点よりもボス側に位置するよう設計する。このように鉄道用車輪の板部形状をかかる構成とすることで、安全率のさらなる向上、ひいては板部の板厚を薄くし、軽量化を図りつつも従来と同様またはそれ以上の安全率を確保することが可能となる。
【００２９】
第２及び第４発明にあっては、リム部がボス部に対して、内輪側に偏心しているＢ形車輪の場合、ボス部フィレット、板部及びリム部フィレットの径方向の断面形状を規定する２つの曲線のうち、外輪側の曲線の接線と、ボス側線分の法線とのなす角を計測し、その最大値をとる外輪側の曲線上の点が、ボス側線分及びリム側線分から等距離の位置に形成される補助線分が外輪側の曲線と交差する点よりもボス側に位置するよう設計する。または、ボス側線分からと、リム側線分からとの距離比が０．５５対０．４５の位置に形成される補助線分が内輪側の曲線と交差する点よりもボス側に位置するよう設計する。このように、リム部の偏心方向と逆方向の板部曲線の形状をかかる形状とすることで、板部の板厚を薄くし、軽量化を図りつつも従来と同様またはそれ以上の安全率を確保でき、さらに鉄道車両の高速化及び省エネルギー化を図ることが可能となる等、本発明は優れた効果を奏し得る。
【図面の簡単な説明】
【図１】Ａ形車輪の径方向の断面形状を示す断面図である。
【図２】Ｂ形車輪の径方向の断面形状を示す断面図である。
【図３】機械的応力の概念を説明する模式図である。
【図４】最大角α_ｍａｘをとる点の位置を変化させた場合の、当該車輪の安全率の推移を示す特性図ある。
【図５】Ａ形車輪の径方向の断面形状を示す断面図である。
【図６】Ｂ形車輪の径方向の断面形状を示す断面図である。
【図７】Ｃ形車輪の径方向の断面形状を示す断面図である。
【符号の説明】
１　　　車輪
１Ａ　　Ａ形車輪
１Ｂ　　Ｂ形車輪
１１　　ボス部
１２　　ボス部フィレット
１３　　板部
１４　　リム部フィレット
１５　　リム部
１６　　フランジ
ａｂ　　曲線
ｃｄ　　曲線
ａｃ　　ボス側線分
ｂｄ　　リム側線分[0001]
TECHNICAL FIELD OF THE INVENTION
A type or B type comprising a boss portion, a boss portion fillet, a plate portion, a rim portion fillet, a rim portion and a flange from the inside to the outside, wherein the rim portion is eccentric to the outer ring side or the inner ring side with respect to the boss portion. In particular, the present invention relates to a railway wheel having an optimized shape of a plate portion between a boss portion fillet and a rim portion fillet.
[0002]
[Prior art]
2. Description of the Related Art From the viewpoint of increasing the speed of railway vehicles and saving energy, it is desired to reduce the weight of railway wheels (hereinafter referred to as wheels). Although the weight of the wheel can be reduced by reducing the plate thickness of the plate portion, the reduction in the plate thickness lowers the breakage resistance. Therefore, it is necessary to reduce the weight of the wheels while maintaining the breakage resistance.
[0003]
Conventional railway wheels are designed in accordance with, for example, Japanese Industrial Standard JIS E5402-1989. In such a standard, three types of railway wheels, namely A type, B type and C type, are specified. 5 is a cross-sectional view showing a radial cross-sectional shape of an A-type wheel, FIG. 6 is a cross-sectional view showing a radial cross-sectional shape of a B-type wheel, and FIG. 7 is a cross-sectional view showing a radial cross-sectional shape of a C-type wheel. It is. From the boss portion 11A into which the axle (not shown) is inserted, the boss portion fillet 12A, the plate portion 13A, the rim portion fillet 14A, the rim portion 15A, and the flange 16A protruding from the inner wheel side of the wheel are formed in an A-shape. A wheel 10A is formed. The A-shaped wheel 10A is defined as having a shape in which the rim 15A is eccentric to the outer ring with respect to the boss 11A. According to JIS standard 5402-1989, the length of each part is as shown in Table 1 below. Stipulated.
[0004]
[Table 1]

[0005]
As shown in FIG. 6, the B-shaped wheel 10B also has a boss portion fillet 12B, a plate portion 13B, a rim portion fillet 14B, a rim portion 15B, and a boss portion 11B from the boss portion 11B into which an axle (not shown) is inserted. The B-shaped wheel 10B is formed from the flange 16B protruding from the inner wheel side of the wheel. The B-type wheel 10B is defined to have a shape in which the rim portion 15B is eccentric to the inner ring side with respect to the boss portion 11B, contrary to the A-type wheel 10A, and according to JIS standard 5402-1989, The length is defined as shown in Table 2 below.
[0006]
[Table 2]

[0007]
As shown in FIG. 7, the C-shaped wheel 10C used for the Shinkansen and the like also has a boss portion fillet 12C that extends outward from a boss portion 11C into which an axle (not shown) is inserted similarly to other wheels, as shown in FIG. A C-shaped wheel 10C is formed from the plate portion 13C, the rim fillet 14C, the rim portion 15C, and the flange 16C protruding from the wheel inner ring side. Unlike the A-type wheel 10A and the B-type wheel 10B, the C-type wheel 10C is defined as a shape in which the rim portion 15C is not eccentric with respect to the boss portion 11C neither on the inner ring side nor on the outer ring side. According to 1989, the length of each part is defined as shown in Table 3 below.
[0008]
[Table 3]

[0009]
[Patent Document 1]
JP-A-10-29401
[Problems to be solved by the invention]
However, for example, thicker and _t 2 = _22mm~26mm at _t 1 = 18 mm, the boss-side plate thickness of the conventional wheel plate portion as shown in Table 1 is the rim side, faster railway by weight of the wheel And it was difficult to achieve energy saving. Further, when the sheet thickness is reduced in order to reduce the weight, there is a problem that the breakage resistance increases and the safety factor decreases. When the stress (mechanical stress) generated by the reaction force from the rail increases, the breakage resistance increases and the safety factor decreases. The applicant of the present application has conducted intensive studies to develop a wheel capable of reducing the thickness of the plate portion and reducing the weight while maintaining or improving the safety factor. By making the curve shape on the inner ring side a specific shape among the two curves defining the cross-sectional shape in the radial direction, it is possible to improve the safety factor while reducing the thickness of the plate portion. I found that.
[0011]
On the other hand, in the case of a B-type wheel, the thickness of the plate portion is made similar to that of the A-type wheel by making the curve shape on the outer ring side a specific shape among the two curves defining the radial cross-sectional shape of the plate portion. It was also found that it was possible to improve the safety factor while reducing the thickness.
[0012]
The present invention has been made in view of such knowledge, and an object of the present invention is to provide an A-shaped wheel, among two curves defining a cross-sectional shape in a radial direction of a plate portion, a curve on an inner wheel side. By setting the shape to a specific shape, and in the case of a B-type wheel, by setting the curved shape on the outer ring side to a specific shape, even if the plate thickness is reduced, the same safety factor as before can be achieved. It is to provide a railway wheel that can be maintained.
[0013]
[Means for Solving the Problems]
The railway wheel according to the first invention has a boss portion, a boss portion fillet, a plate portion, a rim portion fillet, a rim portion, and a flange from the inside to the outside, and the rim portion is on the outer ring side with respect to the boss portion. Of the two curves that define the radial cross-sectional shape of the boss portion fillet, the plate portion, and the rim portion fillet, the rail wheel is eccentric to the tangent to the curve on the inner ring side, and is fitted to the boss portion. A point on the curve of the inner ring side plate portion that takes the maximum value of the angle formed by the normal to the axis of the axle, the boss side line segment defined by the intersection of the two curves and the boss portion, and An auxiliary line segment formed at a position equidistant from a rim side line segment defined by an intersection of the two curves and the rim portion is located closer to the boss than a point intersecting the inner ring side curve. .
[0014]
The railway wheel according to the second invention has a boss portion, a boss portion fillet, a plate portion, a rim portion fillet, a rim portion, and a flange from inside to outside, and the rim portion is on the inner wheel side with respect to the boss portion. Of the two curves defining the radial cross-sectional shape of the boss portion fillet, the plate portion, and the rim portion fillet, the rail wheel is eccentric to the tangent line of the curve on the outer ring side, and is fitted to the boss portion. A point on the curve of the outer ring side plate portion that takes the maximum value of the angle formed by the normal to the axis of the axle, the boss side line segment defined by the intersection of the two curves and the boss portion, and An auxiliary line segment formed at a position equidistant from a rim side line segment defined by an intersection between the two curves and the rim portion is located closer to the boss than a point intersecting the outer ring side curve. .
[0015]
The railway wheel according to the third invention has a boss portion, a boss portion fillet, a plate portion, a rim portion fillet, a rim portion, and a flange from the inside to the outside, and the rim portion is on the outer ring side with respect to the boss portion. Of the two curves that define the radial cross-sectional shape of the boss portion fillet, the plate portion, and the rim portion fillet, the rail wheel is eccentric to the tangent to the curve on the inner ring side, and is fitted to the boss portion. The point on the curve of the inner ring side plate portion, which takes the maximum value of the angle formed by the normal to the axis of the axle, is determined from the boss side line segment defined by the intersection of the two curves and the boss portion. The auxiliary line segment formed at a distance ratio of 0.55 to 0.45 from the rim side line segment defined by the intersection between the two curves and the rim portion is more boss than the point where the auxiliary line segment intersects the inner ring side curve. Located on the side
[0016]
The railway wheel according to the fourth invention has a boss, a boss fillet, a plate, a rim fillet, a rim, and a flange from the inside to the outside, and the rim is on the inner wheel side with respect to the boss. Of the two curves defining the radial cross-sectional shape of the boss portion fillet, the plate portion, and the rim portion fillet, the rail wheel is eccentric to the tangent line of the curve on the outer ring side, and is fitted to the boss portion. The point on the curve of the outer ring side plate portion, which takes the maximum value of the angle formed by the normal to the axis of the axle, is determined from the boss side line segment defined by the intersection of the two curves and the boss portion. The auxiliary line segment formed at a distance ratio of 0.55 to 0.45 from the rim side line segment defined by the intersection between the two curves and the rim portion is more boss than the point where the auxiliary line segment intersects the outer ring side curve. Located on the side .
[0017]
In the first and third inventions, in the case of an A-shaped wheel in which the rim portion is eccentric to the outer ring side with respect to the boss portion, the radial cross-sectional shapes of the boss portion fillet, the plate portion, and the rim portion fillet are defined. Of the two curves to be performed, attention is paid to the curve on the inner ring side. The curve ranges from a boss side line segment defined by the intersection of the two curves and the boss portion to a rim side line segment defined by the intersection of the two curves and the rim portion. Measure the angle between the tangent of the curve on the inner ring side and the normal to the axis of the axle that is inserted into the boss, and the point on the curve of the inner ring side plate that takes the maximum value is the boss side line and the rim. It is determined that the auxiliary line segment formed at a position equidistant from the side line segment is located closer to the boss than the point where it intersects the curve on the inner wheel side. In addition, in order to make the safety factor equal to or higher than that of the conventional wheel, an experiment described later shows that the tangent of the curve on the inner ring side and the curve of the inner ring side plate portion that takes the maximum value of the angle formed by the normal to the boss side line are calculated. The point is such that the auxiliary line segment formed at a distance ratio of 0.55 to 0.45 from the boss side line segment to the rim side line segment is located closer to the boss than the point where it intersects the curve on the inner ring side. Just do it. By adopting such a configuration of the plate part of the railway wheel, the safety factor is further improved, and as a result, the thickness of the plate part is reduced, and the same or higher safety factor is ensured while reducing the weight. Becomes possible.
[0018]
In the second and fourth inventions, in the case of a B-type wheel in which the rim portion is eccentric to the inner ring side with respect to the boss portion, the radial cross-sectional shapes of the boss portion fillet, the plate portion, and the rim portion fillet are defined. Of the two curves to be performed, attention is paid to the curve on the outer ring side. Similarly, the angle between the tangent of the curve on the outer ring side and the normal to the axis of the axle inserted into the boss is measured, and the point on the curve on the outer ring that takes the maximum value is the line segment on the boss side. In addition, it is determined that the auxiliary line segment formed at a position equidistant from the rim side line segment is located closer to the boss than the point where the auxiliary line segment intersects the curve on the outer ring side. Or, in order to make the safety factor equal to or higher than that of the conventional wheel, it is necessary to determine the maximum value of the angle between the tangent of the curve on the outer ring side and the normal to the boss side line by the experiment described later. The point may be located closer to the boss than the point where the auxiliary line formed at a distance ratio of 0.55 to 0.45 between the boss side line and the rim side line intersects the outer ring side curve. . In this way, by making the shape of the plate portion curve in the direction opposite to the eccentric direction of the rim portion into such a shape, the thickness of the plate portion is reduced, and the safety factor is equal to or higher than the conventional one while reducing the weight. , And it is possible to further increase the speed and energy saving of the railway vehicle.
[0019]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, the present invention will be described in detail with reference to the drawings showing embodiments.
Embodiment 1
FIG. 1 is a cross-sectional view showing a radial cross-sectional shape of an A-shaped wheel 1A (represented by the wheel 1 in some cases). The A-shaped wheel 1A includes a boss 11, a boss fillet 12, a plate 13, a rim fillet 14, a rim 15, and a flange 16 from the inside to the outside. Eccentric. The boss portion 11 into which the axle (not shown) is inserted perpendicular to the radial direction is formed with a boss portion fillet 12 reaching the plate portion 13, and the wheel thickness is adjusted via the boss portion fillet 12 to the boss portion 11. From the boss height H to the plate thickness t ₂ of the plate portion 13 (boss side). The length of each part is as shown in Table 1.
[0020]
One end of the plate 13 is joined to the boss fillet 12 described above, while the other end of the plate 13 is joined to the rim fillet 14. The cross-sectional shape in the radial direction of the plate portion 13 is a curve st and a curve uw, and a line segment su and a curve st and a curve defined by respective intersections s and u between the curve st and the curve uw and the boss portion fillet 12. It is constituted by a line segment tw defined by respective intersections t and w between uw and the rim portion fillet 14. Further, two curves defining the radial cross-sectional shapes of the boss portion fillet, the plate portion, and the rim portion fillet include a curve ab and a curve cd as shown in FIG. The point a is the intersection between the curve ab on the inner ring side and the boss 11, and the point c is the intersection between the curve cd on the outer ring and the boss 11. Hereinafter, the line segment ac is referred to as a boss side line segment. Similarly, a point b is an intersection between the curve ab on the inner wheel side and the rim portion 15, and a point d is an intersection between the curve cd on the outer wheel side and the rim portion 15. Hereinafter, the line segment bd is referred to as a rim-side line segment. The plate portion 13 is joined to the rim portion 15 via the rim portion fillet 14, and the wheel thickness is changed from the plate thickness t ₁ (rim side) of the plate portion 13 to the rim width B while passing through the rim portion fillet 14. Expand to Further, a flange is protruded from the inner ring side end of the rim portion 15.
[0021]
In the A-type wheel 1A, of the two curves ab and cd defining the cross-sectional shapes of the boss portion fillet 12, the plate portion 13, and the rim portion fillet 14, attention is paid to the curve ab on the inner wheel side, particularly the curve st. An angle between a tangent L at an arbitrary point on the curve ab and a normal h to the axis Z of the axle (not shown) inserted into the boss portion is defined as α. In the wheel according to the present invention, preferably, a point on the curve st of the inner ring side plate portion having the maximum angle α _max of α is formed at a position equidistant from the boss side line ac and the rim side line bd, and the boss side line ac The auxiliary line segment parallel to the rim side line segment bd may be positioned closer to the boss than the point e that intersects the curve ab on the inner ring side. That is, the shape of the plate portion 13 is designed so that the maximum angle α _max is formed at any position between the point s and the point e which is the intersection of the auxiliary line segment and the curve ab. Alternatively, a point on the curve st of the inner ring side plate portion having the maximum angle α _max of α is formed at a position where the distance ratio between the boss side line segment ac and the rim side line segment bd is 0.55 to 0.45. It is sufficient that the auxiliary line segment parallel to the boss side line segment ac and the rim side line segment bd is positioned closer to the boss than the point e ′ that intersects the curve ab on the inner ring side. That is, the shape of the plate portion 13 is designed so that the maximum angle α _max is formed at any position between the point s and the point e ′ which is the intersection of the auxiliary line segment and the curve ab. That is, in the A-shaped wheel 1A eccentric to the outer ring side, the plate portion 13 is formed so that the angle α between the tangent line L on the boss portion 11 side and the normal h in the opposed inner ring side curve st becomes maximum. By designing, it is possible to improve the safety factor.
[0022]
FIG. 2 is a cross-sectional view showing a cross-sectional shape in the radial direction of the B-type wheel 1B. Similarly, the B-shaped wheel 1B also includes a boss 11, a boss fillet 12, a plate 13, a rim fillet 14, a rim 15, and a flange 16 from the inside to the outside. It is eccentric to the inner ring side.
[0023]
In the B-shaped wheel 1B, of the two curves ab and cd defining the cross-sectional shapes of the boss part fillet 12, the plate part 13, and the rim part fillet 14, attention is paid to the curve cd on the outer ring side, particularly the curve uw. An angle between a tangent L at an arbitrary point on the curve cd and a normal h to the axis Z is defined as α. In the wheel according to the present invention, preferably, a point on the curve uw of the outer ring side plate portion having the maximum angle α _max of α is formed at a position equidistant from the boss side line ac and the rim side line bd, and the boss side line ac The auxiliary line segment parallel to the rim-side line segment bd may be positioned closer to the boss than the point f that intersects the outer ring-side curve cd. That is, the shape of the plate portion 13 is designed so that the maximum angle α _max is formed at any position between the point u and the point f which is the intersection of the auxiliary line segment and the curve cd. Alternatively, a point on the curve cd of the outer side plate portion having the maximum angle α _max of α is formed at a position where the distance ratio between the boss side line segment ac and the rim side line segment bd is 0.55 to 0.45. Then, the auxiliary line segment parallel to the boss side line segment ac and the rim side line segment bd may be positioned closer to the boss than a point f 'that intersects the outer ring side curve cd. That is, the shape of the plate portion 13 is designed so that the maximum angle α _max is formed at any position between the point s and the point f ′ which is the intersection of the auxiliary line segment and the curve cd. That is, in the B-shaped wheel 1B which is eccentric to the inner ring side, the plate portion 13 is formed so that the angle α between the tangent line L on the boss portion 11 side and the normal h in the opposing outer ring side curve uw becomes maximum. By designing, it is possible to improve the safety factor.
[0024]
Subsequently, an experiment was conducted to see how the safety factor changes by changing the position on the curve that takes the maximum angle α _max . In the experiment, the A86E shown in Table 1 among the A-shaped wheels 1A was used, and FEM (Finite Element Method) analysis was performed on the wheels 1 in which the shape of the plate portion 13 was changed, and the vertical pressure and the lateral pressure were measured. The stress generated in the plate portion 13 when the pressure was applied and the stress generated when the vertical pressure and the back pressure were applied were determined, and the breakage resistance (safety factor) of each plate shape was evaluated.
[0025]
Hereinafter, the vertical pressure, the lateral pressure, and the back pressure will be described. FIG. 3 is a schematic diagram illustrating the concept of mechanical stress. As shown in FIGS. 3A and 3B, the mechanical stress includes a vertical pressure P ₁ , a lateral pressure P ₂ , and a back pressure P ₃ . During straight pass, the wheel load, the wheel tread Q is a bonding surface of the rim portion 15 and the rail R are loaded vertically pressure P ₁ from the rail R. During curving, lateral force P ₂ is loaded from the track inside the rail R in the flange 16. Further, the guide rail P or unillustrated point for derailment, the back pressure P ₃ is loaded from the track outside flange 16.
[0026]
FIG. 4 is a characteristic diagram showing a change in the safety factor of the wheel when the position of the point having the maximum angle α _max is changed. The vertical axis indicates the safety factor, and the safety factor of the conventional wheel is evaluated as 1.0. The horizontal axis indicates the position of the auxiliary line segment. 0 is the same position as the boss side line ac, 0.5 is the position equidistant from the boss side line and the rim side line bd, and 1 is the same position as the rim side line bd. . Here, the point at which the angle α between the tangent L and the normal h at the point on the inner curve st on the curve ab becomes the maximum value α _max is determined by changing the minimum safety factor of each wheel while changing the position. It was determined by FEM analysis of the entire plate portion. Samples 1 to 5 were prepared for analysis. Sample 1 is a conventional wheel, and samples 3 to 5 except for

samples

1 and 2 are A-shaped wheels 1A according to the present invention. The maximum angle α _max of each sample is α _max1 = 39.9 ° (sample 1), α _max2 = 40.7 ° (sample 2), α _max3 = 33.4 ° (sample 3), α _max4 = 35.5 ° (sample 4) and α _max5 = 36.0 ° (sample 5).
[0027]
As a result of the analysis, it can be understood that the safety factor is high when the maximum value α _max is taken from 0 to 0.55 as shown in Samples 3 to 5. In particular, it has been confirmed that the safety factor tends to increase from 0.55 to 0.5, and that when it is 0.5 or less, a high safety factor can be secured even when various conditions such as the inner diameter of the boss and the wheel load change. On the other hand, when it exceeds 0.55 as in the case of the sample 2, it can be understood that the safety factor is not so different from the wheel according to the conventional sample 1. By determining the point having the maximum value α _max at a specific position (point s to point e or point e ′), it is possible to improve the safety factor. Note that similar results were obtained for the B-type wheels, and thus detailed description is omitted. Further, in all of the samples 1 to 5 described above, the change in the safety factor was examined by setting the plate thickness t ₁ (rim side) of the plate portion 13 to 18 mm and the plate thickness t ₂ (boss side) to 22 mm. The thickness may be appropriately changed so as to be 0.0 or more. In this case, it was confirmed that the safety factor was 1.0 or more when the plate thickness of the plate portion 13 was in the range of 1.2% to 2.4% with respect to the rim outer diameter D. For example, in the case of a wheel having a rim outer diameter D of 860 mm, a safety factor of 1.0 or more can be ensured if the plate thickness is in the range of 10.32 mm to 20.64 mm. Thereby, the thickness of the plate portion 13 can be reduced while securing the safety factor.
[0028]
【The invention's effect】
As described in detail above, in the first and third aspects of the present invention, in the case of an A-shaped wheel in which the rim portion is eccentric to the outer ring side with respect to the boss portion, the diameter of the boss portion fillet, the plate portion, and the rim portion fillet Of the two curves that define the cross-sectional shape in the direction, the angle between the tangent to the curve on the inner ring side and the normal to the boss side line is measured, and the point on the curve of the inner ring side plate that takes the maximum value is: An auxiliary line segment formed at a position equidistant from the boss side line segment and the rim side line segment is designed to be located closer to the boss than a point intersecting the curve on the inner ring side. Alternatively, the auxiliary line segment formed at a distance ratio of 0.55 to 0.45 from the boss side line segment to the rim side line segment is designed so as to be located closer to the boss than a point where it intersects the curve on the inner ring side. . By adopting such a configuration of the plate portion of the railway wheel in this way, the safety factor is further improved, and thus the plate portion is made thinner, and the safety factor is equal to or higher than the conventional one while reducing the weight. It is possible to secure.
[0029]
In the second and fourth inventions, in the case of a B-type wheel in which the rim portion is eccentric to the inner ring side with respect to the boss portion, the radial cross-sectional shapes of the boss portion fillet, the plate portion, and the rim portion fillet are defined. Of the two curves, the angle between the tangent of the outer ring side curve and the normal to the boss side line is measured, and the point on the outer ring side curve that takes its maximum value is calculated from the boss side line and the rim side line. The auxiliary line segment formed at the equidistant position is designed to be located on the boss side with respect to the intersection with the curve on the outer ring side. Alternatively, the auxiliary line segment formed at a distance ratio of 0.55 to 0.45 from the boss side line segment to the rim side line segment is located closer to the boss than a point where the auxiliary line intersects the curve on the inner ring side. . In this way, by making the shape of the plate portion curve in the direction opposite to the eccentric direction of the rim portion into a shape, the thickness of the plate portion is reduced, and the safety factor is equal to or higher than the conventional one while reducing the weight. Thus, the present invention can provide excellent effects such as ensuring high speed and energy saving of railway vehicles.
[Brief description of the drawings]
FIG. 1 is a cross-sectional view showing a radial cross-sectional shape of an A-type wheel.
FIG. 2 is a cross-sectional view illustrating a radial cross-sectional shape of a B-type wheel.
FIG. 3 is a schematic diagram illustrating the concept of mechanical stress.
FIG. 4 is a characteristic diagram showing a change in the safety factor of the wheel when the position of a point having a maximum angle α _max is changed.
FIG. 5 is a cross-sectional view showing a radial cross-sectional shape of an A-type wheel.
FIG. 6 is a sectional view showing a radial cross-sectional shape of a B-type wheel.
FIG. 7 is a cross-sectional view showing a radial cross-sectional shape of a C-type wheel.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Wheel 1A A type wheel 1B B type wheel 11 Boss part 12 Boss part fillet 13 Plate part 14 Rim part fillet 15 Rim part 16 Flange ab Curve cd Curve ac Boss side line segment bd Rim side line segment

Claims

From the inside to the outside, a boss portion, a boss portion fillet, a plate portion, a rim portion fillet, a rim portion, and a railway wheel having the flange, wherein the rim portion is eccentric to the outer ring side with respect to the boss portion,
Of the two curves defining the radial cross-sectional shape of the boss portion fillet, the plate portion, and the rim portion fillet, a tangent to an inner ring side curve and a normal to an axis of an axle inserted into the boss portion. The point on the curve of the inner ring side plate that takes the maximum value of the angle
A boss side line segment defined by the intersection of the two curves and the boss portion, and an auxiliary line segment formed at a position equidistant from the rim side line segment defined by the intersection of the two curves and the rim portion Are located closer to the boss than to the point where they intersect the curve on the inner wheel side.

From the inside to the outside, a boss portion, a boss portion fillet, a plate portion, a rim portion fillet, a rim portion, and a railway wheel having a flange, wherein the rim portion is eccentric to the inner ring side with respect to the boss portion,
Of the two curves that define the radial cross-sectional shape of the boss fillet, the plate portion, and the rim fillet, a tangent to an outer ring side curve and a normal to an axis of an axle inserted into the boss. The point on the curve of the outer ring side plate that takes the maximum value of the angle
A boss side line segment defined by the intersection of the two curves and the boss portion, and an auxiliary line segment formed at a position equidistant from the rim side line segment defined by the intersection of the two curves and the rim portion Is located closer to the boss than a point that intersects the curve on the outer ring side.

From the inside to the outside, a boss portion, a boss portion fillet, a plate portion, a rim portion fillet, a rim portion, and a railway wheel having the flange, wherein the rim portion is eccentric to the outer ring side with respect to the boss portion,
Of the two curves defining the radial cross-sectional shape of the boss portion fillet, the plate portion, and the rim portion fillet, a tangent to an inner ring side curve and a normal to an axis of an axle inserted into the boss portion. The point on the curve of the inner ring side plate that takes the maximum value of the angle
The distance ratio between the boss side line segment defined by the intersection of the two curves and the boss portion and the rim side line segment defined by the intersection point of the two curves and the rim portion is 0.55 to 0.45. A railway wheel, characterized in that the auxiliary line segment formed at the position (1) is located closer to the boss than a point where the auxiliary line segment intersects the curve on the inner wheel side.

From the inside to the outside, a boss portion, a boss portion fillet, a plate portion, a rim portion fillet, a rim portion, and a railway wheel having a flange, wherein the rim portion is eccentric to the inner ring side with respect to the boss portion,
Of the two curves that define the radial cross-sectional shape of the boss fillet, the plate portion, and the rim fillet, a tangent to an outer ring side curve and a normal to an axis of an axle inserted into the boss. The point on the curve of the outer ring side plate that takes the maximum value of the angle
The distance ratio between the boss side line segment defined by the intersection of the two curves and the boss portion and the rim side line segment defined by the intersection point of the two curves and the rim portion is 0.55 to 0.45. A railroad wheel, characterized in that the auxiliary line segment formed at the position of (1) is located on the boss side with respect to the intersection with the curve on the outer ring side.