【０００１】
【発明の属する技術分野】
この発明に係る玉軸受用冠型保持器は、各種回転機械装置の回転部分を支持する為の玉軸受に組み込んで、複数の玉を転動自在に保持する為に利用する。
【０００２】
【従来の技術】
各種回転部分を支持する為に、例えば図１１に示す様な玉軸受１が広く使用されている。この玉軸受１は、外周面に内輪軌道２を形成した内輪３と、内周面に外輪軌道４を形成した外輪５とを同心に配置し、上記内輪軌道２と外輪軌道４との間に複数個の玉６、６を転動自在に設けて成る。これら各玉６、６は、保持器８により転動自在に保持している。又、上記外輪５の両端部内周面には、それぞれ円輪状のシールド板７、７の外周縁を係止し、これら両シールド板７、７によって、上記玉６、６を設置した部分に存在するグリース等の潤滑剤が外部に漏洩したり、或は外部に浮遊する塵芥がこの設置部分に進入したりするのを防止している。尚、密封装置として、上記非接触型のシールド板７、７に代えて、接触型のシール板を使用する場合もある。又、グリース等の潤滑剤は、玉軸受１の回転を円滑に行なわせると共に、この玉軸受１での振動及び騒音を抑え、更に焼き付きを防止する為に、この玉軸受１の内部に充填する。
【０００３】
上記保持器８は、所謂冠型保持器と呼ばれるもので、図１２〜１３に示す様に構成している。この保持器８は、円環状の主部９と、この主部９の軸方向片面に等間隔に設けられた複数のポケット１０、１０とを備える。これら各ポケット１０、１０は、上記主部９の軸方向片面（図１２の表側面、図１３の上側面）に互いに間隔をあけて配置した１対ずつの弾性片１１、１１と、上記主部９の片面でこれら１対ずつの弾性片１１、１１の間部分に設けた凹面部１２とから構成している。そして、上記各ポケット１０、１０に上記玉６（図１１参照）を１個ずつ、転動自在に保持自在としている。この様に構成する各ポケット１０、１０の内面は、単一の中心を有する部分球状凹面としている。又、この球状凹面の曲率半径は、上記各玉６の転動面の曲率半径よりも僅かに大きくしている。この様な保持器８は、合成樹脂を射出成形する事により、一体に形成している。
【０００４】
玉軸受１を組み立てる際に、上記各玉６、６は、上記各ポケット１０、１０を構成する１対ずつの弾性片１１、１１の先端部同士の間隔を弾性的に押し広げつつ、これら１対の弾性片１１、１１同士の間に押し込む。そして、押し込んだ状態では、上記各玉６、６を上記各ポケット１０、１０内に転動自在に保持する。
この状態で、上記各玉６、６の転動面と上記各ポケット１０、１０の内面との間には、微小な隙間が存在する。従って、上記各玉６、６を上記各ポケット１０、１０に保持した状態では、上記保持器８がこれら各玉６、６を円周方向に関して等間隔に、且つ転動自在に保持すると共に、これら各玉６、６によって上記保持器８の直径方向位置を規制する。尚、図１４に示す様に、主部９の軸方向他面（図１４の下側面）で、各ポケット１０から円周方向に外れた部分の複数個所に凹部１３、１３を形成した場合には、上記保持器８の形状精度の向上、並びに、上記主部９の軽量化を図れる。又、この主部９を弾性変形し易くして、上記各ポケット１０に玉６を組み込んだ状態で、内輪３の外周面と外輪５（図１１参照）の内周面との間の適正位置にこれら各玉６を配列し易くする事もできる。
【０００５】
上述の様な玉軸受１に組み込んだ保持器８を構成する各弾性片１１、１１は、円環状に形成した主部９の軸方向片面に、片持ち状態で結合している。言い換えれば、これら各弾性片１１、１１の先端は、他の部分に結合されない自由端となっている。この為、例えば特許文献１に記載されている様に、玉軸受１が高速回転した場合に、上記各弾性片１１、１１が遠心力の作用により外径側へ変形する事が考えられる。又、この様な変形は、周囲が高温になって合成樹脂の硬度が低下する場合に著しくなる。この様に各弾性片１１、１１が変形した場合には、各ポケット１０、１０から各玉６、６が外れる原因となる。又、これら各ポケット１０、１０から各玉６、６が外れない場合でも、これら各ポケット１０、１０の内面と各玉６、６の転動面との間の隙間が大きくなり、保持器８の直径方向に関する変位量が大きくなって、保持器音と呼ばれる騒音や振動が発生し易くなる。
又、上記各弾性片１１、１１の先端部が外輪５等の他の部材と擦れ合って、摩擦熱により当該部分の温度が上昇し、焼き付きが生じる原因となる。
【０００６】
この様な事情に鑑みて、上記特許文献１に記載された従来構造の第１例及び特許文献２に記載された従来構造の第２例の場合には、主部のうち、各弾性片と軸方向に関して反対側の軸方向片面に円環状に形成した金属製の補強板を結合する事により、これら各弾性片が外径側に変形する事を抑えている。又、特許文献３に記載された従来構造の第３例の場合には、各弾性片の先端部同士を連結環により連結している。この様な従来構造の第３例の場合には、保持器が高速回転する場合でも、各弾性片が遠心力により外径側へ変形する事を防止できる。
【０００７】
［特許文献１］
特開平８−１４５０６１号公報
［特許文献２］
実開平６−８８２１号公報
［特許文献３］
実開平６−１８４８号公報
【０００８】
【発明が解決しようとする課題】
上記特許文献１〜３に記載された従来構造の第１〜３例の場合には、それぞれ次の様な不都合がある。先ず、上記特許文献１、２に記載された従来構造の第１、２例の場合には、金属製の補強板を保持器の軸方向片面に結合している為、重量が嵩む事が避けられない。又、上記特許文献３に記載された従来構造の第３例の場合には、各弾性片の先端部同士を連結環により連結している為、軸方向寸法が嵩んで、玉軸受が大型化したり、或は、玉軸受の内部空間の容積が小さくなる原因となる。この様に内部空間の容積が小さくなる場合には、内部に封入するグリース等の潤滑剤の量が少なくなり、焼き付きが発生し易くなる等、耐久性が低下する原因となる。
【０００９】
これに対して、保持器を構成する主部の円周方向複数個所で、各ポケットの底部に位置する部分の肉厚を大きくして、この部分の剛性を高くする事により、各弾性片の外径側への変形を防止する事も、従来から考えられている。但し、この様にした場合も、やはり重量が嵩んだり、軸方向寸法が嵩んだり、玉軸受の内部空間の容積が小さくなる原因となる。又、保持器の径方向に関する厚さを、各弾性片の先端縁に向かう程薄くする事により、この保持器が高速回転した場合でもこれら各弾性片が外径側に変形するのを防止する事も、従来から考えられている。但し、この様にした場合には、各ポケットの内面で玉を案内する部分の面積が小さくなる為、これら各玉により保持器の径方向に関する動きを、十分に規制する事が難しくなる。
【００１０】
又、本発明の発明者は、種々の解析を行なった結果から次の様に考えた。
▲１▼ 従来構造の保持器の場合には、主部の殆どの部分が、各玉からの負荷を受け持つ役目を果たさない。
▲２▼ 保持器が回転した場合での、各弾性片の先端縁の径方向に関する変位量は、主部の円周方向複数個所で弾性片の基端部を結合した部分に遠心力が作用する事により、これら各弾性片を外径側へ変位させようとする動きと、上記主部の円周方向複数個所でこれら各弾性片と軸方向に関して反対側の部分に遠心力が作用する事により、この部分と軸方向反対側に位置する弾性片を内径側へ変位させようとする動きとのバランスにより、殆ど定まる。
【００１１】
これに対して、前述した従来構造の各例の場合には、主部のうち、各玉からの負荷を殆ど受け持たない、各ポケットの間に位置する部分の厚さが大きくなっている。この為、この主部の円周方向複数個所で各弾性片と軸方向に関して反対側の部分の剛性が高くなっている。逆に、上記主部の円周方向複数個所でこれら各弾性片の基端部を結合した部分の剛性は低くなっている。この為、各弾性片の先端縁は、遠心力が作用する事により外径側へ変位し易い。
【００１２】
一方、上記主部の円周方向複数個所で上記各弾性片と軸方向に関して反対側の部分の剛性が低過ぎた場合には、この部分が外径側へ変位すると共に、この部分と軸方向反対側に位置する弾性片の先端縁が内径側へ変位する。この場合には、これら各弾性片の先端縁が外輪に対し擦れ合う事はなくなるが、内輪に対し擦れ合う可能性がある。
本発明は、この様な事情に鑑みて、上述した従来構造で生じる不都合を何れも解消すべく発明したものである。
【００１３】
【課題を解決するための手段】
本発明の玉軸受用冠型保持器は、前述の図１２〜１４に示した従来の保持器と同様に、合成樹脂により一体に造られて、全体を円環状に形成した主部と、この主部の円周方向複数個所に設けられた、それぞれの内周面を凹面としたポケットとを備える。又、これら各ポケットは、上記主部の一部に互いに間隔をあけて配置された１対ずつの弾性片同士の間に設けられたものである。
【００１４】
特に、本発明の玉軸受用冠型保持器に於いては、上記主部の円周方向複数個所で円周方向に関して隣り合うポケットの間に位置する部分を連結部とし、この主部の円周方向複数個所で上記各ポケットの底部に位置する部分を、上記連結部とは軸方向にずれた底壁部としている。そして、回転時に上記各連結部とこれら各連結部に結合した１対の弾性片とに作用する遠心力に基づく、これら各連結部の上記各底壁部に対する捩れ変形と、上記主部の円周方向複数個所で上記各連結部よりも軸方向に関して上記各底壁部側に外れた部分に作用する遠心力に基づく、これら各底壁部のこれら各連結部に対する捩れ変形とで、静止状態での各部に対する捩れ変形の方向を互いに逆にすると共に、互いの捩れ角の大きさを実質的に同じにしている。尚、これら捩れ角のうち、上記各連結部とこれら各連結部に結合した１対ずつの弾性片とに作用する遠心力に基づく、これら各連結部の上記各底壁部に対する捩れ変形の捩れ角とは、静止状態でのこれら各連結部の側面の任意の点に関する接平面と、回転時でのこの任意の点に関する接平面とがなす角度とする。又、上記主部の円周方向複数個所で上記各連結部よりも軸方向に関して上記各底壁部側に外れた部分に作用する遠心力に基づく、これら各底壁部のこれら各連結部に対する捩れ変形の捩れ角とは、静止状態でのこれら各底壁部の側面の任意の点に関する接平面と、回転時でのこの任意の点に関する接平面とがなす角度とする。
【００１５】
又、請求項２に記載した玉軸受用冠型保持器の場合には、上記各底壁部のうちのポケットと反対側の端縁と上記各弾性片の先端縁との間の軸方向に関する距離である保持器幅をＷとし、上記各底壁部のうちのポケットと反対側の端縁と上記各連結部の軸方向中央位置との間の軸方向に関する距離をＬとした場合に、０．４５Ｗ≦Ｌ≦０．７０Ｗを満たしている。
【００１６】
又、請求項３に記載した玉軸受用冠型保持器の場合には、上記各底壁部のうちのポケットと反対側の端縁と上記各弾性片の先端縁との間の軸方向に関する距離である保持器幅をＷとし、上記各連結部の軸方向両側面同士の間の長さである連結部厚さをＴとした場合に、０．１４Ｗ≦Ｔ≦０．１６Ｗを満たしている。
【００１７】
【作用】
上述の様に構成する本発明の玉軸受用冠型保持器が、各ポケットに玉を、１個ずつ転動自在に保持する作用は、前述した従来構造の場合と同様である。特に、本発明の玉軸受用冠型保持器の場合、高速回転する状態で使用した場合でも、各弾性片の先端縁等の各部の径方向への変位を抑える事ができる。この為、保持器の径方向に関する変位を抑えると共に、上記保持器と外輪等の他の部材との接触を防止できる。そして、玉軸受の運転時に、騒音や振動が発生する事を抑えられる。又、本発明の玉軸受用冠型保持器を組み込んだ玉軸受の内部での、この保持器が占める容積を小さくできる為、軽量化を図れると共に、この玉軸受の内部に封入するグリースの量を多くできる。
【００１８】
又、請求項２に記載した玉軸受用冠型保持器によれば、上記各弾性片の先端縁の外径側への変位を抑える事ができる構造を、容易に得られる。
【００１９】
又、請求項３に記載した玉軸受用冠型保持器によれば、上記各連結部に加わる応力を抑える事と、上記各弾性片の外径側への変位を小さくする事とを、高次元で両立できる。
【００２０】
【発明の実施の形態】
図１〜２は、本発明の実施の形態の第１例を示している。本発明の保持器８ａは、前述の図１２〜１４に示した従来構造と同様に、合成樹脂を射出成形する事により一体に形成したもので、全体を円環状に形成した主部９と、この主部９の一部に軸方向片面（図１、２の上側面）に開口する状態で円周方向複数個所に設けられ、それぞれの内周面を凹面とした、玉６（図１１参照）を１個ずつ転動自在に保持する為のポケット１０、１０とを備える。又、これら各ポケット１０、１０は、上記主部９の軸方向片面に互いに間隔をあけて配置した１対ずつの弾性片１１、１１同士の間部分に設けている。これら各ポケット１０、１０の内面は、上記各玉６の転動面の曲率半径よりも僅かに大きな曲率半径を有する部分球状凹面である。
【００２１】
又、本例の場合には、上記主部９の軸方向他面（図１、２の下側面）の円周方向複数個所に凹部１４、１４を形成する事により、この主部９の一部で円周方向に関して隣り合うポケット１０、１０の間に位置する部分に、軸方向に関する厚さが小さくなった連結部１５、１５を設けている。又、上記主部９の円周方向複数個所で上記各ポケット１０、１０の底部に位置する部分である底壁部１６、１６の軸方向に関する厚さを、前述した従来構造と同様に大きくしている。この様に各底壁部１６、１６の厚さを大きくしている理由は、これら各底壁部１６、１６は、保持器８ａの回転時に、負荷が加わり易い部分であり、この部分の強度を確保する必要がある為である。
【００２２】
又、上記保持器８ａを構成する合成樹脂として、直鎖状ポリフェニレンサルファイド、ポリアミド６６、ポリアミド４６、分枝状ポリフェニレンサルファイド等を使用している。又、上記保持器８ａの機械的強度を向上させる為に、上記合成樹脂に、繊維系又は粒子系の充填剤を添加している。繊維系の充填剤としては、ガラス繊維やカーボン繊維等を好ましく使用でき、粒子系の充填剤としては、シリカやアルミナ等を好ましく使用できる。
【００２３】
特に、本発明の場合には、上記保持器８ａが回転した場合に、上記各連結部１５、１５とこれら各連結部１５、１５に結合した１対の弾性片１１、１１とに作用する遠心力に基づく、これら各連結部１５、１５の上記各底壁部１６、１６に対する捩れ変形と、上記主部９の円周方向複数個所で上記各連結部１５、１５よりも軸方向に関して上記各底壁部１６、１６側に外れた部分に作用する遠心力に基づく、これら各底壁部１６、１６のこれら各連結部１５、１５に対する捩れ変形とを考える。そして、それぞれの変形の、静止状態でのこれら各部に対する捩れ方向を互いに逆にすると共に、捩れ角の大きさを互いに実質的に同じにしている。尚、これら両捩れ角は、使用回転速度の全範囲に亙って同じにする事は難しい。従って、実質的に同じとは、最も使用頻度が高い回転速度範囲で、（大きい方の捩れ角を基準として）差が２０％の範囲、より好ましくは１０％の範囲に収まる状態を言う。
【００２４】
尚、これら捩れ角のうち、上記各連結部１５、１５とこれら各連結部１５、１５に結合した１対の弾性片１１、１１とに作用する遠心力に基づく、これら各連結部１５、１５の上記各底壁部１６、１６に対する捩れ変形の捩れ角とは、静止状態でのこれら各連結部１５、１５の側面１５ａ、１５ａの任意の点に関する接平面と、回転時でのこの任意の点に関する接平面とがなす角度とする。又、上記主部９の円周方向複数個所で上記各連結部１５、１５よりも軸方向に関して上記各底壁部１６、１６側に外れた部分に作用する遠心力に基づく、これら各底壁部１６、１６のこれら各連結部１５、１５に対する捩れ変形の捩れ角とは、静止状態でのこれら各底壁部１６、１６の側面１６ａ（図２）の任意の点に関する接平面と、回転時でのこの任意の点に関する接平面とがなす角度とする。
【００２５】
使用時に於ける各部の捩れ角を上述の様に規制する為に、本例の場合には、これら各連結部１５、１５を、上記各玉６の中心を通るピッチ円と軸方向に関してほぼ一致する（ピッチ円が各連結部１５、１５の厚さ範囲内を通る）位置に設けている。より具体的には、上記各底壁部１６、１６のうちのポケット１０、１０と反対側の端縁と上記各弾性片１１、１１の先端縁との間の軸方向に関する距離である保持器幅をＷ（図２）とし、上記各底壁部１６、１６のうちのポケット１０、１０を形成した側と反対側の端縁と上記各連結部１５、１５の軸方向中央位置との間の軸方向に関する距離をＬ（図２）とした場合に、０．４５Ｗ≦Ｌ≦０．７０Ｗを満たす様に各部の寸法を規制している。又、好ましくは、０．６０Ｗ≦Ｌ≦０．６５Ｗを満たす様に、各部の寸法を規制する。更に、本例の場合には、上記各連結部１５、１５の軸方向両側面同士の間の長さである連結部厚さをＴ（図２）とした場合に、０．４５Ｗ≦Ｌ≦０．７０Ｗを満たす様に各部の寸法を規制している。
【００２６】
上述の様に構成する本発明の玉軸受用冠型保持器の場合には、高速回転する状態で使用した場合でも、各弾性片１１、１１の先端縁等の各部の径方向への変位を抑える事ができる。この為、各ポケット１０、１０の内面の玉６の転動面との間の隙間が広がる事を抑え、保持器８ａの径方向に関する変位を抑えて、保持器音の発生を防止できる。又、保持器８ａと外輪５（図１１参照）等の他の部材との接触を防止して、騒音や振動の発生を抑える事ができる。又、上記保持器８ａを組み込んだ玉軸受の内部での、この保持器８ａが占める容積を小さくできる為、軽量化を図れると共に、この玉軸受の内部に封入するグリースの量を多くできる。
【００２７】
又、本例の場合には、保持器幅Ｗと、各底壁部１６、１６のうちのポケット１０、１０と反対側の端縁と各連結部１５、１５の軸方向中央位置との間の軸方向に関する距離Ｌとを適切に規制している為、上記各弾性片１１、１１の先端縁の外径側への変位を抑える事ができる構造を、容易に得られる。更に、本例の場合には、上記保持器幅Ｗと、連結部厚さＴとを適切に規制している為、各連結部１５、１５に加わる応力を抑える事と、上記各弾性片１１、１１の外径側への変位を小さくする事とを、高次元で両立できる。
【００２８】
【実施例】
次に、本発明の発明者が本発明の効果を確認すべく行なった計算（シミュレーション）の結果に就いて説明する。この計算は、外径が４７ｍｍで、内径が１７ｍｍで、幅が１４ｍｍである、単列深溝型の玉軸受で、前述の図１２〜１３に示した従来構造を有する保持器８を使用した従来品と、本発明の構造を有する保持器８ａを使用した本発明品との２種類に就いて行なった。そして、これら２種類の玉軸受を、２２０００ｍｉｎ−１ で回転させた場合での、各部の変形量を求めた。図３、４に、その計算結果を示している。尚、図３は従来品での計算結果を、図４は本発明品での計算結果を、それぞれ示している。又、図３、４中の二点鎖線は、静止状態での保持器８、８ａの外形線を表している。又、図３、４で保持器８、８ａの各面上に描いた曲線（実線）は、変形量が等しくなる点を結んだ等高線であり、これら各曲線に付した数字は変形量の大きさを、ｍｍで表している。又、図３、４で、斜格子で示した各図の下端部分は、最も変形量が小さい部分である事を、梨地で示した各図の上端部分は、最も変形量が大きい部分である事を、それぞれ表している。
【００２９】
上記図３、４に示した計算結果から明らかな様に、本発明の場合には、従来構造の場合に比べて、各弾性片１１の外径側（図３、４の右側）への変位量を小さくできる。尚、図３、４に示した計算結果からも明らかな様に、本発明の場合には、従来構造の場合よりも、主部９の円周方向複数個所で各ポケット１０の底部に位置する部分の外径側への変形量が大きくなっているが、その大きさは各弾性片１１の外径側への変形量よりも小さく、保持器８ａ全体として見た場合に、問題とはならない。
【００３０】
次に、本発明の発明者が本発明の効果を確認する為に行なった別の計算結果に就いて説明する。この第二の計算は、従来品と本発明品とを、２２０００ｍｉｎ−１ で回転させた場合での、各部の応力分布を計算した。図５、６に、その計算結果を示している。尚、図５は従来品での計算結果を、図６は本発明品での計算結果を、それぞれ示している。又、図５、６中の二点鎖線は、静止状態での保持器８、８ａの外形線を表している。又、図５、６で保持器８、８ａの各面に描いた曲線（実線）は、応力が等しくなる点を結んだ等高線であり、これら各曲線に付した数字は応力の大きさを、ＭＰａで表している。又、図５、６で、斜格子で示した部分は最も応力が小さい部分である事を、梨地で示した部分は最も応力が大きい部分である事を、それぞれ表している。
【００３１】
上記図５、６に示した計算結果から明らかな様に、従来品の場合には、主部９のうち、各ポケット１０の底部に位置する部分でのみ応力が大きくなったのに対し、本発明品の場合には、主部９のうち、円周方向に関して隣り合うポケット１０の間に位置する部分である連結部１５と、各ポケット１０の底部に位置する部分である底壁部１６とで、応力が大きくなった。又、本発明品の場合には、従来品の場合に対し、最大応力が小さくなった。この様な第二の計算結果から明らかな様に、本発明の場合には、上記各連結部１５と上記各底壁部１６とで大きく負荷を受け持つ構造となる。
【００３２】
次に、本発明の発明者が、保持器８ａを構成する各底壁部１６と各連結部１５との厚さが、各部の径方向への倒れに及ぼす影響を調べる為に行なった計算に就いて説明する。先ず、前述の図４で各部の変形量の計算結果を示した本発明品に対し、各底壁部１６の厚さを１．７倍程度、各連結部１５の厚さを２倍程度、それぞれ大きくした保持器を、２２０００ｍｉｎ−１ で回転させた場合での、各部の変形量を計算した。図７に、その計算結果を示している。尚、同図中、二点鎖線は、静止状態での保持器８ａの外形を表している。又、同図でこの保持器８ａの各面に描いた曲線（実線）は、変形量が等しくなる点を結んだ等高線であり、これら各曲線に付した数字は変形量の大きさを、ｍｍで表している。又、同図の上端部の斜格子で示した部分は最も変形量が小さい部分である事を、同じく下端部の梨地で示した部分は最も変形量が大きい部分である事を、それぞれ表している。
【００３３】
図７に示した計算結果から明らかな様に、各底壁部１６の厚さを各連結部１５の厚さとの関係で大きくした場合には、これら各底壁部１６が外径側へ、各弾性片１１が内径側へ、それぞれ倒れる状態となった。
【００３４】
次に、図７に示した形状を有する構造に対し、各連結部１５の厚さを同じとしたまま、各底壁部１６の厚さを小さくした保持器を、２２０００ｍｉｎ−１ で回転させた場合での、各部の変形量を計算した。図８に、その計算結果を示している。
図８に示した計算結果から明らかな様に、各底壁部１６の厚さを、各連結部１５の厚さとの関係で小さくした場合には、各底壁部１６が内径側へ、各弾性片１１が外径側へ、それぞれ倒れる状態となった。この様な図７、８に示した計算結果から、各部の径方向への倒れは、各底壁部１６の厚さと各連結部１５の厚さとに影響を受け、これら各部１６、１５の厚さを適切に規制すれば、前述の図４、５で示した様に、各部の径方向への倒れを抑えられる事が分かる。
【００３５】
次に、請求項２に記載した玉軸受用冠型保持器の効果を確認する為に行なった計算結果に就いて説明する。この計算は、保持器８ａに対する各連結部１５、１５の軸方向位置を変化させた場合での、各弾性片１１、１１の先端縁の径方向に関する変位量を計算した。図９に、その計算結果を示している。尚、図９で、横軸は、各底壁部１６、１６のうちのポケット１０、１０と反対側の端縁と各連結部１５、１５の軸方向中央位置との間の軸方向に関する距離Ｌと保持器幅Ｗとの比Ｌ／Ｗを、縦軸は、各弾性片１１、１１の先端縁の径方向に関する変位量の従来品に対する比を、それぞれ表している。又、図９の鎖線イは、各ポケット１０内に組み込んだ玉６のピッチ円の軸方向位置を表している。
【００３６】
図９に示した計算結果から明らかな様に、各連結部１５、１５の軸方向位置が、各ポケット１０内に組み込んだ玉６のピッチ円の軸方向位置付近にある場合には、各弾性片１１、１１の径方向に関する変位量は十分に小さくなり、この変位量の最小値は、同図に破線ロで示す従来品の場合に対し４０％程度小さくなった。又、上記比Ｌ／Ｗが０．４５〜０．７０の範囲内にある場合には、上記各弾性片１１、１１の先端縁の径方向に関する変位量は、従来品の場合よりも小さくなった。又、上記比Ｌ／Ｗが０．６０〜０．６５の範囲内にある場合には、上記各弾性片１１、１１の先端縁の径方向に関する変位量は、十分に小さくなった。この様な計算結果から、請求項２に記載した玉軸受用冠型保持器の効果を確認できた。
【００３７】
次に、請求項３に記載した玉軸受用冠型保持器の効果を確認する為に行なった計算結果に就いて説明する。この計算は、保持器幅Ｗに対する連結部厚さＴの比Ｔ／Ｗを種々に変化させて、各連結部１５、１５に加わる応力と、各弾性片１１、１１の先端縁の径方向に関する変位量とを計算した。図１０に、その計算結果を示している。尚、この図１０で、縦軸は、各弾性片１１、１１の先端縁の径方向に関する変位量の従来品に対する比と、各連結部１５、１５に加わる応力とを、横軸は、保持器幅Ｗに対する連結部厚さＴの比Ｔ／Ｗを、それぞれ表している。
【００３８】
図１０に示した計算結果から明らかな様に、上記保持器幅Ｗに対する連結部厚さＴの比Ｔ／Ｗが小さくなる場合には、上記各弾性片１１、１１の先端縁の径方向に関する変位量が小さくなるのに対し、上記各連結部１５、１５に加わる応力は大きくなる。逆に、上記比Ｔ／Ｗが大きくなる場合には、これら各連結部１５、１５に加わる応力が小さくなる代わりに、上記各弾性片１１、１１の先端縁の径方向に関する変位量は大きくなる。又、上記比Ｔ／Ｗが０．１４〜０．１６の範囲で、上記各弾性片１１、１１の先端縁の変位量は急激に増大し、逆に、上記各連結部１５、１５に加わる応力は急激に減少する。この様な計算結果から明らかな様に、上記比Ｔ／Ｗを０．１４〜０．１６、特に０．１４５〜０．１５５である０．１５０近傍とした場合には、各連結部１５、１５に加わる応力を抑える事と、各弾性片１１、１１の外径側への変位を小さくする事とを、高次元で両立でき、請求項３に記載した玉軸受用冠型保持器の効果を確認できた。
【００３９】
【発明の効果】
本発明の玉軸受用冠型保持器は、以上に述べた通り構成され作用する為、小型且つ軽量な構造で、使用時に他の部材と接触する事を防止して、騒音や振動の発生を抑える事ができると共に、保持器を組み込んだ玉軸受の耐久性向上を図れる。
【図面の簡単な説明】
【図１】本発明の実施の形態の１例を示す斜視図。
【図２】図１の部分拡大斜視図。
【図３】従来品での回転時の各部の変形量に関する計算の結果を、保持器の一部を取り出して示す図。
【図４】本発明品での回転時の各部の変形量に関する計算の結果を、保持器の一部を取り出して示す図。
【図５】従来品での回転時の各部の応力に関する計算の結果を、保持器の一部を取り出して示す図。
【図６】本発明品での回転時の各部の応力に関する計算の結果を、保持器の一部を取り出して示す図。
【図７】底壁部の厚さと連結部の厚さとが、各部の径方向への倒れに及ぼす影響を知る為に行なった第一の計算の結果を、保持器の一部を取り出して示す図。
【図８】同じく第二の計算の結果を、保持器の一部を取り出して示す図。
【図９】比Ｌ／Ｗが、各弾性片の先端縁の径方向に関する変位量に及ぼす影響を調べる為に行なった計算の結果を示す線図。
【図１０】比Ｔ／Ｗが、各弾性片の先端縁の径方向に関する変位量と、各連結部に加わる応力とに及ぼす影響を調べる為に行なった計算の結果を示す線図。
【図１１】保持器を組み込んだ玉軸受の１例を示す断面図。
【図１２】保持器の従来構造の１例を示す斜視図。
【図１３】図１２のＡ−Ａ断面を、切断部分以外を省略して示す図。
【図１４】保持器の従来構造の別例を示す部分切断斜視図。
【符号の説明】
１ 玉軸受
２ 内輪軌道
３ 内輪
４ 外輪軌道
５ 外輪
６ 玉
７ シールド板
８、８ａ 保持器
９ 主部
１０ ポケット
１１ 弾性片
１２ 凹面部
１３ 凹部
１４ 凹部
１５ 連結部
１６ 底壁部[0001]
TECHNICAL FIELD OF THE INVENTION
The crown type retainer for a ball bearing according to the present invention is incorporated in a ball bearing for supporting a rotating portion of various types of rotating machinery, and is used to hold a plurality of balls in a freely rolling manner.
[0002]
[Prior art]
In order to support various rotating parts, a ball bearing 1 as shown in FIG. 11, for example, is widely used. In this ball bearing 1, an inner race 3 having an inner raceway 2 formed on the outer peripheral surface and an outer race 5 having an outer raceway 4 formed on the inner peripheral surface are concentrically arranged. A plurality of balls 6, 6 are provided so as to roll freely. Each of these balls 6, 6 is held by a retainer 8 so as to freely roll. The outer peripheral edges of the annular shield plates 7 and 7 are respectively engaged with the inner peripheral surfaces of both ends of the outer ring 5, and the shield plates 7 and 7 are provided at the portions where the balls 6 and 6 are installed. Lubricants such as grease are prevented from leaking to the outside, or dust floating outside is prevented from entering the installation portion. Incidentally, as the sealing device, a contact-type seal plate may be used instead of the non-contact-type shield plates 7 and 7 in some cases. A lubricant such as grease is filled in the ball bearing 1 to smoothly rotate the ball bearing 1, suppress vibration and noise in the ball bearing 1, and further prevent seizure. .
[0003]
The cage 8 is a so-called crown type cage, and is configured as shown in FIGS. The retainer 8 includes an annular main portion 9 and a plurality of pockets 10, 10 provided at equal intervals on one axial surface of the main portion 9. Each of the pockets 10, 10 is provided with a pair of elastic pieces 11, 11 arranged on one side in the axial direction of the main part 9 (the front side in FIG. 12 and the upper side in FIG. 13) at intervals. The pair of elastic pieces 11 is provided on one surface of the portion 9 and the concave portion 12 is provided between the pair of elastic pieces 11. The balls 6 (see FIG. 11) can be rolled and held in the pockets 10 and 10 one by one. The inner surface of each of the pockets 10 and 10 thus configured is a partially spherical concave surface having a single center. The radius of curvature of the spherical concave surface is slightly larger than the radius of curvature of the rolling surface of each ball 6. Such a retainer 8 is integrally formed by injection molding a synthetic resin.
[0004]
When assembling the ball bearing 1, each of the balls 6, 6 resiliently expands the interval between the tip portions of a pair of elastic pieces 11, 11 constituting each of the pockets 10, 10, It is pushed between the pair of elastic pieces 11 and 11. Then, in the pressed state, the balls 6 are rollably held in the pockets 10.
In this state, there is a minute gap between the rolling surface of each of the balls 6, 6 and the inner surface of each of the pockets 10, 10. Therefore, in a state where the balls 6, 6 are held in the pockets 10, 10, the retainer 8 holds the balls 6, 6 at equal intervals in the circumferential direction and freely rolls. These balls 6 regulate the diametric position of the retainer 8. As shown in FIG. 14, when the concave portions 13 are formed at a plurality of locations on the other surface in the axial direction of the main portion 9 (the lower surface in FIG. Can improve the shape accuracy of the retainer 8 and reduce the weight of the main part 9. In addition, the main portion 9 is easily elastically deformed, and in a state where the balls 6 are incorporated in the respective pockets 10, an appropriate position between the outer peripheral surface of the inner ring 3 and the inner peripheral surface of the outer ring 5 (see FIG. 11). These balls 6 can be easily arranged.
[0005]
Each of the elastic pieces 11 constituting the retainer 8 incorporated in the above-described ball bearing 1 is cantilevered to one axial surface of the main portion 9 formed in an annular shape. In other words, the tip of each of the elastic pieces 11, 11 is a free end that is not connected to another part. Therefore, as described in Patent Document 1, for example, when the ball bearing 1 rotates at a high speed, it is conceivable that the elastic pieces 11, 11 are deformed to the outer diameter side by the action of centrifugal force. Such deformation becomes remarkable when the temperature of the surroundings becomes high and the hardness of the synthetic resin decreases. When the elastic pieces 11 are deformed in this manner, the balls 6, 6 may come off from the pockets 10, 10. Further, even if the balls 6, 6 do not come off from the pockets 10, 10, the gap between the inner surface of each of the pockets 10, 10 and the rolling surface of each of the balls 6, 6 increases, and the cage 8 The displacement amount in the diametrical direction becomes large, and noise and vibration called retainer sound are likely to occur.
In addition, the tip of each of the elastic pieces 11, 11 rubs against another member such as the outer ring 5, so that the temperature of the portion increases due to frictional heat, which causes seizure.
[0006]
In view of such circumstances, in the case of the first example of the conventional structure described in Patent Document 1 and the second example of the conventional structure described in Patent Document 2, By coupling a metal reinforcing plate formed in an annular shape to one surface in the axial direction on the opposite side in the axial direction, deformation of each elastic piece toward the outer diameter side is suppressed. In the case of the third example of the conventional structure described in Patent Document 3, the distal ends of the elastic pieces are connected to each other by a connecting ring. In the case of the third example of such a conventional structure, each elastic piece can be prevented from being deformed to the outer diameter side due to centrifugal force even when the cage rotates at high speed.
[0007]
[Patent Document 1]
JP-A-8-145061
[Patent Document 2]
Japanese Utility Model Publication No. 6-8821
[Patent Document 3]
Japanese Utility Model Laid-Open No. 6-1848
[0008]
[Problems to be solved by the invention]
The first to third examples of the conventional structure described in Patent Documents 1 to 3 have the following disadvantages. First, in the case of the first and second examples of the conventional structure described in Patent Documents 1 and 2, since the metal reinforcing plate is connected to one side in the axial direction of the retainer, the increase in weight is avoided. I can't. Further, in the case of the third example of the conventional structure described in Patent Document 3, since the distal ends of the elastic pieces are connected to each other by the connecting ring, the axial dimension increases, and the size of the ball bearing increases. Or the volume of the internal space of the ball bearing may be reduced. When the volume of the internal space is reduced as described above, the amount of a lubricant such as grease sealed in the interior is reduced, so that seizure is easily generated and the durability is reduced.
[0009]
On the other hand, by increasing the thickness of the portion located at the bottom of each pocket at a plurality of locations in the circumferential direction of the main portion constituting the retainer and increasing the rigidity of this portion, It has been conventionally considered to prevent deformation toward the outer diameter side. However, even in this case, the weight is increased, the dimension in the axial direction is increased, and the volume of the internal space of the ball bearing is reduced. Further, by reducing the thickness of the retainer in the radial direction toward the leading edge of each elastic piece, it is possible to prevent the elastic pieces from being deformed to the outer diameter side even when the retainer rotates at high speed. Things have been considered for some time. However, in such a case, since the area of the portion for guiding the ball on the inner surface of each pocket becomes small, it is difficult to sufficiently restrict the movement of the retainer in the radial direction by each of these balls.
[0010]
The inventor of the present invention considered as follows from the results of various analyzes.
{Circle around (1)} In the case of the cage having the conventional structure, most of the main portion does not serve to bear the load from each ball.
{Circle around (2)} When the cage rotates, the amount of displacement of the distal end edge of each elastic piece in the radial direction depends on the centrifugal force acting on the portion where the base end of the elastic piece is joined at a plurality of circumferential locations of the main part. By doing so, the movement of displacing each of these elastic pieces to the outer diameter side and the centrifugal force acting on the portion on the opposite side to the axial direction with each of these elastic pieces at a plurality of positions in the circumferential direction of the main part. Therefore, it is almost determined by the balance between this portion and the movement of displacing the elastic piece located on the opposite side in the axial direction toward the inner diameter side.
[0011]
On the other hand, in each of the above-described examples of the conventional structure, the thickness of the portion of the main portion that is located between the pockets and hardly receives the load from each ball is large. For this reason, the rigidity of the portion on the opposite side in the axial direction from each elastic piece at a plurality of locations in the circumferential direction of the main portion is increased. Conversely, the rigidity of the portion connecting the base ends of the elastic pieces at a plurality of locations in the circumferential direction of the main portion is low. For this reason, the tip edge of each elastic piece is easily displaced to the outer diameter side due to the centrifugal force acting.
[0012]
On the other hand, when the rigidity of the portion opposite to the elastic piece in the axial direction at a plurality of locations in the circumferential direction of the main portion is too low, this portion is displaced to the outer diameter side, and this portion and the axial direction are displaced. The leading edge of the elastic piece located on the opposite side is displaced toward the inner diameter side. In this case, the leading edge of each of the elastic pieces does not rub against the outer ring, but may rub against the inner ring.
In view of such circumstances, the present invention has been made to solve any inconvenience caused by the above-described conventional structure.
[0013]
[Means for Solving the Problems]
The crown type retainer for a ball bearing of the present invention is, like the conventional retainer shown in FIGS. Pockets provided at a plurality of locations in the circumferential direction of the main portion, each having a concave inner peripheral surface. Further, each of these pockets is provided between a pair of elastic pieces which are arranged at an interval in a part of the main portion.
[0014]
In particular, in the crown type cage for a ball bearing of the present invention, a portion located between pockets adjacent in the circumferential direction at a plurality of positions in the circumferential direction of the main portion is defined as a connecting portion, and a circle of the main portion is formed. A portion located at the bottom of each pocket at a plurality of locations in the circumferential direction is a bottom wall portion that is shifted in the axial direction from the connection portion. Then, based on the centrifugal force acting on each of the connecting portions and the pair of elastic pieces coupled to each of the connecting portions during rotation, the torsional deformation of each of the connecting portions with respect to each of the bottom wall portions and the circle of the main portion are performed. At a plurality of positions in the circumferential direction, the torsional deformation of each of the bottom walls with respect to each of the connecting portions is based on centrifugal force acting on a portion of each of the bottoms closer to the bottom wall in the axial direction than each of the connecting portions. In this case, the directions of the torsional deformation of the respective parts are reversed, and the magnitudes of the torsional angles are substantially the same. Of these torsion angles, the torsional deformation of each of these connecting portions with respect to each of the bottom walls is based on centrifugal force acting on each of the connecting portions and a pair of elastic pieces connected to each of the connecting portions. The angle is an angle formed between a tangent plane at an arbitrary point on the side surface of each of the connecting portions in a stationary state and a tangent plane at an arbitrary point during rotation. In addition, based on centrifugal force acting on a portion of each of the main portions in the circumferential direction at a plurality of locations in the circumferential direction and closer to the bottom wall side than the connection portions, the bottom wall portions are connected to the connection portions. The torsion angle of the torsional deformation is an angle formed between a tangent plane at an arbitrary point on the side surface of each of the bottom walls in a stationary state and a tangent plane at an arbitrary point during rotation.
[0015]
In the case of the ball bearing crown type retainer according to the second aspect, the axial direction between the end edge of the bottom wall portion opposite to the pocket and the tip end edge of each elastic piece. When the retainer width, which is the distance, is W, and the distance in the axial direction between the edge of the bottom wall opposite to the pocket and the axial center position of each connecting portion is L, 0.45W ≦ L ≦ 0.70W is satisfied.
[0016]
Also, in the case of the ball bearing crown type retainer described in claim 3, the axial direction between the end edge of the bottom wall portion opposite to the pocket and the tip end edge of each of the elastic pieces. Assuming that the retainer width, which is the distance, is W, and the connecting portion thickness, which is the length between both axial side surfaces of each of the connecting portions, is T, 0.14W ≦ T ≦ 0.16W is satisfied. I have.
[0017]
[Action]
The operation of the ball bearing crown type retainer of the present invention configured as described above for holding the balls in each pocket one by one so as to freely roll is the same as in the case of the above-described conventional structure. In particular, in the case of the crown type retainer for a ball bearing of the present invention, the radial displacement of each part such as the distal end edge of each elastic piece can be suppressed even when used in a state of high-speed rotation. Therefore, the displacement of the retainer in the radial direction can be suppressed, and the contact between the retainer and another member such as the outer ring can be prevented. Further, generation of noise and vibration during operation of the ball bearing can be suppressed. Further, since the volume occupied by the cage in the ball bearing incorporating the crown type cage for a ball bearing of the present invention can be reduced, the weight can be reduced, and the amount of grease sealed inside the ball bearing. Can be many.
[0018]
Further, according to the crown type retainer for a ball bearing described in claim 2, it is possible to easily obtain a structure capable of suppressing displacement of the distal end edge of each elastic piece toward the outer diameter side.
[0019]
According to the crown type cage for a ball bearing according to the third aspect, it is possible to reduce the stress applied to each of the connecting portions and to reduce the displacement of each of the elastic pieces to the outer diameter side. Can be compatible in dimensions.
[0020]
BEST MODE FOR CARRYING OUT THE INVENTION
1 and 2 show a first example of an embodiment of the present invention. The retainer 8a of the present invention is formed integrally by injection-molding a synthetic resin in the same manner as the conventional structure shown in FIGS. A ball 6 (see FIG. 11) which is provided in a part of the main portion 9 at a plurality of positions in the circumferential direction so as to be open on one surface in the axial direction (the upper surface in FIGS. ) Are provided with pockets 10 and 10 for holding each of them in a freely rolling manner. These pockets 10, 10 are provided in a portion between a pair of elastic pieces 11, 11 arranged at an interval on one side in the axial direction of the main portion 9. The inner surface of each of the pockets 10, 10 is a partially spherical concave surface having a radius of curvature slightly larger than the radius of curvature of the rolling surface of each ball 6.
[0021]
In the case of the present example, the recesses 14 and 14 are formed at a plurality of circumferential positions on the other surface in the axial direction (the lower surface in FIGS. In the portion between the pockets 10 adjacent to each other in the circumferential direction in the portion, connecting portions 15 having a reduced thickness in the axial direction are provided. Further, the thickness of the bottom wall portions 16, 16, which are portions located at the bottoms of the pockets 10 at a plurality of locations in the circumferential direction of the main portion 9, is increased in the axial direction similarly to the above-described conventional structure. ing. The reason why the thickness of each of the bottom wall portions 16 is increased is that these bottom wall portions 16 are portions to which a load is easily applied when the retainer 8a rotates, and the strength of this portion is increased. This is because it is necessary to secure
[0022]
As the synthetic resin constituting the retainer 8a, linear polyphenylene sulfide, polyamide 66, polyamide 46, branched polyphenylene sulfide, or the like is used. In order to improve the mechanical strength of the retainer 8a, a fibrous or particulate filler is added to the synthetic resin. As the fiber-based filler, glass fiber, carbon fiber, or the like can be preferably used, and as the particle-based filler, silica, alumina, or the like can be preferably used.
[0023]
In particular, in the case of the present invention, when the retainer 8a rotates, the centrifugal force acting on each of the connecting portions 15, 15 and the pair of elastic pieces 11, 11 connected to each of the connecting portions 15, 15 is provided. The torsional deformation of the connecting portions 15, 15 with respect to the bottom wall portions 16, 16 based on the force and the axial direction of the connecting portions 15, 15 at a plurality of circumferential positions of the main portion 9. Consider torsional deformation of the bottom walls 16, 16 with respect to the connecting portions 15, 15 based on the centrifugal force acting on the portions off the bottom wall 16, 16. The directions of torsion of the respective deformations with respect to these portions in the stationary state are made opposite to each other, and the magnitudes of the torsion angles are made substantially the same. It is difficult to make these two torsion angles the same over the entire range of the operating rotational speed. Therefore, substantially the same means a state in which the difference falls within the range of 20% (based on the larger torsion angle), more preferably within the range of 10%, in the most frequently used rotational speed range.
[0024]
In addition, among these torsion angles, these connecting portions 15, 15 based on the centrifugal force acting on the connecting portions 15, 15 and the pair of elastic pieces 11, 11, which are connected to the connecting portions 15, 15, respectively. The torsion angle of the torsional deformation with respect to each of the bottom wall portions 16 and 16 is defined by a tangent plane with respect to an arbitrary point on the side surface 15a and 15a of each of the connecting portions 15 and 15 in a stationary state and an arbitrary tangential plane when rotating. The angle between a tangent plane with respect to a point. In addition, based on centrifugal force acting on portions of the main portion 9 at a plurality of positions in the circumferential direction on the bottom wall portions 16 and 16 side in the axial direction with respect to the connection portions 15 and 15, these bottom walls are based on centrifugal force. The torsional angle of the torsional deformation of the portions 16, 16 with respect to each of the connecting portions 15, 15 is defined as the tangent plane of the bottom wall portions 16, 16 in a stationary state with respect to an arbitrary point on the side surface 16 a (FIG. 2), and the rotation. The angle between the tangent plane about this arbitrary point at the time.
[0025]
In order to regulate the torsion angle of each part during use as described above, in the case of this example, these connecting parts 15 and 15 substantially coincide with the pitch circle passing through the center of each ball 6 in the axial direction. (The pitch circle passes through the thickness range of each connecting portion 15, 15). More specifically, the cage is a distance in the axial direction between an edge of each of the bottom walls 16, 16 opposite to the pockets 10, and a tip of each of the elastic pieces 11, 11. The width is defined as W (FIG. 2), and between the bottom edge of each of the bottom walls 16, 16 on the side opposite to the side where the pockets 10, 10 are formed and the axial center of each of the connection portions 15, 15. When the distance in the axial direction is L (FIG. 2), the size of each part is regulated so as to satisfy 0.45 W ≦ L ≦ 0.70 W. Also, preferably, the dimensions of each part are regulated so as to satisfy 0.60 W ≦ L ≦ 0.65 W. Further, in the case of the present example, when the thickness of the connecting portion, which is the length between the two axial side surfaces of the connecting portions 15 and 15, is T (FIG. 2), 0.45 W ≦ L ≦ The size of each part is regulated so as to satisfy 0.70 W.
[0026]
In the case of the crown type cage for a ball bearing of the present invention configured as described above, the radial displacement of each part such as the distal end edge of each elastic piece 11, 11 can be reduced even when the ball bearing is used at a high speed. Can be suppressed. For this reason, it is possible to prevent the gap between the inner surface of each of the pockets 10 and 10 from rolling with the rolling surface of the ball 6, suppress the radial displacement of the retainer 8a, and prevent the generation of retainer noise. Further, contact between the retainer 8a and other members such as the outer ring 5 (see FIG. 11) can be prevented, and generation of noise and vibration can be suppressed. Further, since the volume occupied by the cage 8a inside the ball bearing in which the cage 8a is incorporated can be reduced, the weight can be reduced, and the amount of grease sealed inside the ball bearing can be increased.
[0027]
In the case of this example, between the retainer width W and the end of each of the bottom walls 16, 16 on the side opposite to the pockets 10, and the central position in the axial direction of each of the connecting parts 15, 15. Since the distance L in the axial direction is appropriately regulated, a structure capable of suppressing the displacement of the distal end edges of the elastic pieces 11, 11 toward the outer diameter side can be easily obtained. Further, in the case of the present example, since the retainer width W and the connecting portion thickness T are appropriately regulated, the stress applied to the connecting portions 15 and 15 is suppressed, and the elastic pieces 11 , 11 can be reduced at a high dimension.
[0028]
【Example】
Next, the results of calculations (simulations) performed by the inventor of the present invention to confirm the effects of the present invention will be described. This calculation is based on a conventional single-row, deep-groove type ball bearing having an outer diameter of 47 mm, an inner diameter of 17 mm, and a width of 14 mm, using the cage 8 having the conventional structure shown in FIGS. The test was performed on two types of products: a product of the present invention using the retainer 8a having the structure of the present invention. Then, these two types of ball bearings are used for 22000 min. -1 The amount of deformation of each part in the case of rotating at was determined. 3 and 4 show the calculation results. FIG. 3 shows the calculation results for the conventional product, and FIG. 4 shows the calculation results for the product of the present invention. In addition, the two-dot chain lines in FIGS. 3 and 4 represent the outlines of the retainers 8 and 8a in the stationary state. Curves (solid lines) drawn on each surface of the cages 8 and 8a in FIGS. 3 and 4 are contour lines connecting points at which the deformation amounts are equal, and the numbers attached to these curves indicate the magnitudes of the deformation amounts. Is expressed in mm. Also, in FIGS. 3 and 4, the lower end portion of each diagram indicated by a diagonal lattice is a portion having the smallest deformation amount, and the upper end portion of each diagram indicated by a satin finish is a portion having the largest deformation amount. It represents each thing.
[0029]
As is clear from the calculation results shown in FIGS. 3 and 4, in the case of the present invention, the displacement of each elastic piece 11 toward the outer diameter side (the right side in FIGS. The amount can be reduced. As is clear from the calculation results shown in FIGS. 3 and 4, in the case of the present invention, the position is located at the bottom of each pocket 10 at a plurality of positions in the circumferential direction of the main part 9 as compared with the case of the conventional structure. Although the amount of deformation of the portion toward the outer diameter is large, the size is smaller than the amount of deformation of each elastic piece 11 toward the outer diameter, and does not pose a problem when viewed as a whole of the retainer 8a. .
[0030]
Next, another calculation result performed by the inventor of the present invention to confirm the effect of the present invention will be described. In this second calculation, the conventional product and the product of the present invention were compared for 22,000 min. -1 The stress distribution of each part when rotating at was calculated. 5 and 6 show the calculation results. FIG. 5 shows the calculation results for the conventional product, and FIG. 6 shows the calculation results for the product of the present invention. 5 and 6, the two-dot chain line indicates the outline of the retainers 8, 8a in the stationary state. The curves (solid lines) drawn on the respective surfaces of the cages 8 and 8a in FIGS. 5 and 6 are contour lines connecting points at which the stresses are equal, and the numbers attached to these curves indicate the magnitudes of the stresses. It is expressed in MPa. In FIGS. 5 and 6, the portions indicated by diagonal lattices indicate portions having the lowest stress, and the portions indicated by satin areas indicate portions having the highest stress, respectively.
[0031]
As is clear from the calculation results shown in FIGS. 5 and 6, in the case of the conventional product, the stress increased only in the portion of the main portion 9 located at the bottom of each pocket 10, whereas in the case of the conventional product, the stress increased. In the case of the invention, the connecting portion 15, which is a portion of the main portion 9 located between the adjacent pockets 10 in the circumferential direction, and the bottom wall portion 16, which is a portion located at the bottom of each pocket 10. As a result, the stress increased. In the case of the product of the present invention, the maximum stress was smaller than that of the conventional product. As is clear from the second calculation result, in the case of the present invention, the structure in which the connection portions 15 and the bottom wall portions 16 bear a large load is adopted.
[0032]
Next, the calculation performed by the inventor of the present invention to examine the effect of the thickness of each bottom wall portion 16 and each connecting portion 15 constituting the retainer 8a on the fall of each portion in the radial direction is described. I will explain this. First, the thickness of each bottom wall portion 16 is about 1.7 times, and the thickness of each connecting portion 15 is about twice that of the present invention, which shows the calculation results of the deformation amount of each portion in FIG. Each cage was enlarged for 22000min -1 The amount of deformation of each part when rotating at was calculated. FIG. 7 shows the calculation result. Note that, in the drawing, a two-dot chain line indicates the outer shape of the retainer 8a in a stationary state. In the same drawing, the curves (solid lines) drawn on each surface of the retainer 8a are contour lines connecting points at which the deformation amounts are equal, and the numbers attached to these curves indicate the magnitude of the deformation amount in mm. It is represented by Also, the portion indicated by the oblique lattice at the upper end of the figure represents that the deformation amount is the smallest, and the portion indicated by the satin at the lower end is the portion having the largest deformation amount, respectively. I have.
[0033]
As is clear from the calculation results shown in FIG. 7, when the thickness of each bottom wall portion 16 is increased in relation to the thickness of each connecting portion 15, each of the bottom wall portions 16 moves to the outer diameter side, Each of the elastic pieces 11 fell down to the inner diameter side.
[0034]
Next, with respect to the structure having the shape shown in FIG. 7, a retainer in which the thickness of each bottom wall portion 16 is reduced while keeping the thickness of each connecting portion 15 the same is used for 22000 min. -1 The amount of deformation of each part when rotating at was calculated. FIG. 8 shows the calculation results.
As is clear from the calculation results shown in FIG. 8, when the thickness of each bottom wall portion 16 is reduced in relation to the thickness of each connection portion 15, each bottom wall portion 16 moves The elastic pieces 11 fell down toward the outer diameter. From the calculation results shown in FIGS. 7 and 8, the falling of each part in the radial direction is affected by the thickness of each bottom wall part 16 and the thickness of each connecting part 15, and the thickness of each part 16, 15 It can be seen that, if the height is appropriately regulated, as shown in FIGS.
[0035]
Next, calculation results performed for confirming the effect of the crown type cage for a ball bearing described in claim 2 will be described. In this calculation, the amount of displacement in the radial direction of the distal end edge of each elastic piece 11, 11 when the axial position of each connecting portion 15, 15 with respect to the retainer 8a is changed. FIG. 9 shows the calculation result. In FIG. 9, the horizontal axis represents the distance in the axial direction between the edge of each of the bottom walls 16, 16 on the opposite side to the pockets 10, and the central position in the axial direction of each of the connecting portions 15, 15. The ordinate represents the ratio L / W of L to the retainer width W, and the ordinate represents the ratio of the amount of displacement of the distal end edge of each elastic piece 11 in the radial direction to the conventional product. 9 indicates the axial position of the pitch circle of the ball 6 incorporated in each pocket 10.
[0036]
As is clear from the calculation results shown in FIG. The amount of displacement of the pieces 11 in the radial direction became sufficiently small, and the minimum value of this amount of displacement was reduced by about 40% from the case of the conventional product shown by the broken line B in FIG. When the ratio L / W is in the range of 0.45 to 0.70, the amount of displacement of the distal ends of the elastic pieces 11 in the radial direction is smaller than that of the conventional product. Was. When the ratio L / W was in the range of 0.60 to 0.65, the amount of displacement of the distal end edges of the elastic pieces 11 in the radial direction was sufficiently small. From such a calculation result, the effect of the crown type cage for a ball bearing described in claim 2 could be confirmed.
[0037]
Next, calculation results performed to confirm the effect of the ball bearing crown type retainer according to claim 3 will be described. This calculation is performed by variously changing the ratio T / W of the thickness T of the connecting portion to the width W of the retainer, and relates to the stress applied to each connecting portion 15 and the radial direction of the distal end edge of each elastic piece 11. The amount of displacement was calculated. FIG. 10 shows the calculation result. In FIG. 10, the vertical axis represents the ratio of the displacement of the distal end edge of each elastic piece 11, 11 in the radial direction to the conventional product, and the stress applied to each connecting portion 15, and the horizontal axis represents the holding. The ratio T / W of the connection portion thickness T to the container width W is shown.
[0038]
As is clear from the calculation results shown in FIG. 10, when the ratio T / W of the connecting portion thickness T to the cage width W becomes smaller, the radial direction of the distal end edge of each of the elastic pieces 11 is increased. While the amount of displacement is reduced, the stress applied to each of the connecting portions 15, 15 is increased. Conversely, when the ratio T / W increases, the amount of displacement in the radial direction of the distal end edge of each of the elastic pieces 11 increases instead of the stress applied to each of the connecting portions 15 decreasing. . Further, when the ratio T / W is in the range of 0.14 to 0.16, the displacement of the leading edge of each of the elastic pieces 11, 11 increases sharply, and conversely, it is applied to each of the connecting portions 15, 15. The stress decreases sharply. As is clear from such calculation results, when the above ratio T / W is set to 0.14 to 0.16, particularly around 0.150 which is 0.145 to 0.155, each connecting portion 15 4. The ball bearing crown type retainer according to claim 3, wherein a reduction in stress applied to the elastic member 15 and a reduction in the displacement of the elastic pieces 11, 11 toward the outer diameter side can be achieved at a high level. Was confirmed.
[0039]
【The invention's effect】
Since the crown type cage for a ball bearing of the present invention is configured and operates as described above, it has a small and lightweight structure, prevents contact with other members during use, and reduces noise and vibration. It is possible to improve the durability of the ball bearing in which the cage is incorporated, as well as to suppress it.
[Brief description of the drawings]
FIG. 1 is a perspective view showing an example of an embodiment of the present invention.
FIG. 2 is a partially enlarged perspective view of FIG.
FIG. 3 is a diagram illustrating a calculation result regarding a deformation amount of each part at the time of rotation of a conventional product by extracting a part of a cage.
FIG. 4 is a diagram showing a result of calculation regarding the amount of deformation of each part during rotation of the product of the present invention by extracting a part of the cage.
FIG. 5 is a diagram showing a calculation result regarding stress of each part during rotation of a conventional product, with a part of a cage taken out.
FIG. 6 is a diagram illustrating a calculation result regarding stress of each part during rotation of the product of the present invention, showing a part of a retainer.
FIG. 7 shows a result of a first calculation performed to know the influence of the thickness of the bottom wall portion and the thickness of the connection portion on the radial inclination of each portion, by extracting a part of the cage. FIG.
FIG. 8 is a diagram showing a result of the second calculation by extracting a part of the cage.
FIG. 9 is a diagram showing the results of calculations performed to investigate the effect of the ratio L / W on the amount of displacement of the leading edge of each elastic piece in the radial direction.
FIG. 10 is a diagram showing the results of calculations performed to investigate the effect of the ratio T / W on the amount of displacement of the distal end edge of each elastic piece in the radial direction and the stress applied to each connecting portion.
FIG. 11 is a sectional view showing an example of a ball bearing incorporating a retainer.
FIG. 12 is a perspective view showing an example of a conventional structure of a cage.
FIG. 13 is a diagram illustrating a cross section taken along line AA of FIG. 12 except for a cut portion.
FIG. 14 is a partially cut perspective view showing another example of the conventional structure of the cage.
[Explanation of symbols]
1 Ball bearing
2 Inner ring track
3 Inner ring
4 Outer ring raceway
5 Outer ring
6 balls
7 Shield plate
8, 8a Cage
9 Main part
10 pockets
11 Elastic pieces
12 Concave surface
13 recess
14 recess
15 Connecting part
16 Bottom wall
