JP2004019822A

JP2004019822A - Bearing device, method of manufacturing coil spring, and evaluation tool for coil spring

Info

Publication number: JP2004019822A
Application number: JP2002177257A
Authority: JP
Inventors: Seizo Miyazaki; 宮崎　晴三; Hiroyuki Mitsune; 三根　裕之
Original assignee: NSK Ltd
Current assignee: NSK Ltd
Priority date: 2002-06-18
Filing date: 2002-06-18
Publication date: 2004-01-22

Abstract

PROBLEM TO BE SOLVED: To provide a bearing device, in which the tilts of outer rings of 1st and 2nd bearing parts respectively are made small so as to comparatively easily build the bearing parts in a housing, and also provide a manufacturing method of a coil spring, and an evaluation tool for the coil spring. SOLUTION: The bearing device 10 includes the 1st bearing part 15 and the 2nd bearing part 25 installed coaxially along a shaft 12. A coil spring 35 for imparting pre-load is inserted between the parts 15 and 25. Further, in a free state of the coil spring 35, a winding-end position P1 is placed in the inside of a position P2 by 0.5 winding in the direction of a winding axis 37 of the winding. COPYRIGHT: (C)2004,JPO

Description

【０００１】
【発明の属する技術分野】
本発明は、例えばＶＴＲやテープストリーマ用のドラムスピンドルモータ、ＬＢＰ用モータやＨＤＤモータなどのディスクメモリスピンドルモータ、ＨＤＤのスイングアームの回転支持部やその他のモータに組み込まれる軸受装置に関し、さらに軸受装置に組み込まれるコイルばねの製造方法およびコイルばねの評価冶具に関する。
【０００２】
【従来の技術】
ＶＴＲやテープストリーマ用のドラムスピンドルモータなどには、そのスピンドル（以下、「軸」という）を支承するために軸受装置が使用されている。この軸受装置としては、例えば実開平４−８２４２５号公報「転がり軸受装置」が知られている。
【０００３】
この公報の軸受装置は、一例としてスピンドルモータの軸に所定間隔をおいて第１軸受部および第２軸受部が備えられ、第１軸受部および第２軸受部間にコイルばねが介装され、このコイルばねで第１軸受部の外輪および第２軸受部の外輪に予圧を付与している。
なお、第１軸受部および第２軸受部のそれぞれの外輪は、例えばハウジングに組み込まれる。
【０００４】
【発明が解決しようとする課題】
ところで、上記公報のコイルばねで第１軸受部の外輪および第２軸受部の外輪に予圧を付与すると、第１、第２軸受部のそれぞれの外輪に偏荷重がかかるために、これらの外輪が軸芯に対して傾いてしまうことが考えられる。
【０００５】
それぞれの外輪の傾きが大きいと、第１、第２軸受部をＶＴＲなどの高精度のハウジングに組み込む際に、引っかかりが生じて外輪の軌道面にブリネリングなどの傷をつけてしまう虞がある。軌道輪に傷がつくと、傷音が発生し軸受装置としては好ましくない。
このため、外輪の軌道面にブリネリングなどの傷をつけないように、第１、第２軸受部をハウジングに組み込む必要があるので、第１、第２軸受部の組み込みに手間がかかる。
【０００６】
また、第１、第２軸受部のそれぞれの外輪の傾きが修正されないままハウジングに固定されると、軸芯に対してハウジングの振れまわりが大きくなり、テープの案内が規格範囲に入らない虞がある。
【０００７】
この不具合を解消するために、コイルばねの座巻き部を研削して、座巻き部が軸芯に対して直角度を保つようにする方法が採用されているが、研削工程が加わるため、コイルばねのコスト低減を図る妨げになっていた。
【０００８】
加えて、コイルばねを第１、第２軸受部の外輪間に組み込む前の状態で座巻き部の直角度を出しても、コイルばねを第１、第２軸受部の外輪間に組み込んでコイルばねが圧縮された際に、座巻き部は直角度が保たれない。
このため、第１、第２軸受部のそれぞれの外輪に偏荷重がかかり、これらの外輪が軸芯に対して傾いてしまうことが考えられる。
【０００９】
よって、前述したように、第１、第２軸受部の組み込みに手間がかかるという不具合や、軸芯に対してハウジングの振れまわりが大きくなるという不具合が発生る虞がある。
【００１０】
本発明は、前述した問題点に鑑みてなされたものであり、その目的は、第１、第２軸受部のそれぞれの外輪の傾きを小さくして、第１、第２軸受部をハウジングに比較的容易に組み込むことができる軸受装置、コイルばねの製造方法およびコイルばねの評価冶具を提供することにある。
【００１１】
【課題を解決するための手段】
前述した目的を達成するために、本発明は、請求項１に記載したように、軸に沿って同軸配置された第１軸受部および第２軸受部を有し、前記第１軸受部および前記第２軸受部間に予圧を付与するためのコイルばねが介装された軸受装置であって、前記コイルばねの自由状態における巻き端位置が、０．５巻き位置よりも巻軸方向内側に配置されていることを特徴とする。
【００１２】
このように構成された軸受装置においては、コイルばねの自由状態における巻き端位置を、０．５巻き位置よりも巻軸方向内側に配置することで、第１、第２軸受部の外輪にコイルばねで偏荷重をかけないようにできる。
よって、第１、第２軸受部の外輪を軸芯に対して傾かないようにセットできるので、第１、第２軸受部をＶＴＲなどのハウジングに組み込む際に引っかかりが生じ難い。
【００１３】
また、第１、第２軸受部の外輪がハウジングに組み込まれた際に、軸芯に対するハウジングの振れまわりを抑えることができる。
さらに、座巻き部を研削することで軸芯に対する座巻き部の直角度を保つ必要がなく、研削工程を省くことができ。
【００１４】
また、本発明においては、請求項２に記載したように、前記巻き端位置が、前記０．５巻き位置よりも前記コイルばねの線径寸法の３０％〜１２０％巻軸方向内側に配置されていることを特徴とする。
【００１５】
巻き端位置を、０．５巻き位置よりもコイルばねの線径寸法の３０％〜１２０％巻軸方向内側に配置することで、第１、第２軸受部の外輪にコイルばねでより確実に偏荷重をかけないようにできる。
よって、第１、第２軸受部の外輪を軸芯に対して傾かないようにセットできるので、第１、第２軸受部をＶＴＲなどのハウジングに組み込む際に、より確実に引っかかりが生じ難くできる。
【００１６】
また、第１、第２軸受部の外輪がハウジングに組み込まれた際に、軸芯に対するハウジングの振れまわりをより確実に抑えることができる。
【００１７】
また、本発明においては、請求項３に記載したように、軸受装置の軸に沿って同軸配置された第１軸受部および第２軸受部間に介装されて予圧を付与するコイルばねの製造方法であって、評価用軸部材に同軸配置された評価用第１軸受部および評価用第２軸受部間に前記コイルばねを介装するとともに、前記評価用第１軸受部および評価用第２軸受部を相対的に近接させることにより実使用条件下となるように前記コイルばねを圧縮させ、前記評価用第１軸受部の外輪および評価用第２軸受部の外輪を回転させながら前記各外輪のうちの一方における端面の周振れを測定手段により測定し、前記測定手段の測定値に基づいて前記コイルばねの自由状態における巻き端位置を調整することを特徴とする。
【００１８】
このように構成されたコイルばねの製造方法においては、評価用第１、第２軸受部間にコイルばねを介装した後、コイルばねを実使用条件下となるように圧縮し、評価用第１、２の軸受部の外輪を回転させながら外輪の周振れを測定し、この測定値に基づいてコイルばねの自由状態における巻き端位置を調整できる。
よって、コイルばねの自由状態における巻き端位置の調整を簡単に確実におこなうことができる。
【００１９】
また、本発明においては、請求項４に記載したように、軸受装置の軸に沿って同軸配置された第１軸受部および第２軸受部間に介装されて予圧を付与するコイルばねの評価冶具であって、評価用軸部材と、前記評価用軸部材を支持する支持手段と、前記評価用軸部材に同軸配置された評価用第１軸受部および評価用第２軸受部と、前記評価用第１軸受部および評価用第２軸受部の外輪のうちの一方における端面の周振れを測定可能な測定手段とを有し、前記評価用第１軸受部および評価用第２軸受部間に前記コイルばねを介装するとともに、前記評価用第１軸受部および評価用第２軸受部を相対的に近接させることにより実使用条件下となるように前記コイルばねを圧縮させ、前記各外輪を回転させながら前記測定手段により前記周振れを測定することを特徴とする。
【００２０】
このように構成されたコイルばねの評価冶具においては、評価用軸部材を支持する支持手段を有し、評価用軸部材に同軸配置された評価用第１、第２の軸受部を有し、評価用第１、第２の軸受部の外輪のうちの一方の周振れを測定する測定手段とを有するだけなので、コイルばねの評価冶具を簡単な構成にできる。
【００２１】
【発明の実施の形態】
以下、本発明に係る実施形態を図面に基づいて詳細に説明する。なお、以下に説明する各実施形態において、既に図１〜図６において説明した部材等については、図中に同一符号あるいは相当符号を付すことにより説明を簡略化あるいは省略する。
【００２２】
図１に示すように、第１実施形態第１実施形態の軸受装置１０は、一例としてＶＴＲやテープストリーマ用のドラムスピンドルモータ（図示せず）の軸１２に沿って同軸配置された第１軸受部１５および第２軸受部２５を有し、第１、第２軸受部１５，２５のそれぞれの内輪軌道１３，１４が軸１２の外周に一定間隔をおいて形成され、第１軸受部１５および第２軸受部２５間に予圧を付与するためのコイルばね３５が介装されている。
このコイルばね３５は、第１軸受部１５の外輪１６に備えた第１ばね座１７と、第２軸受部２５の外輪２６に備えた第２ばね座２７との間に介装されている。
【００２３】
第１軸受部１５は、外輪１６と内輪軌道１３との間に複数個の転動体１８が配置され、複数個の転動体１８は保持器１９で保持されている。
また、第２軸受部２５は、外輪２６と内輪軌道１４との間に複数個の転動体２８が配置され、複数個の転動体２８は保持器２９で保持されている。
以下、コイルばね３５の形状を評価する評価冶具４０について説明する。
【００２４】
図２に示すように、コイルばねの評価冶具４０は、評価用軸部材４１と、評価用軸部材４１を支持する支持手段４５と、評価用軸部材４１に同軸配置された抜差し軸受（評価用第１軸受部）５５および評価用軸受部（評価用第２軸受部）６０と、評価用第２軸受部６０の外輪６１のうちの抜差し軸受５５から離れた方向を向く開放端面６１Ａの周振れを測定可能な測定手段６５とを有する。
【００２５】
支持手段４５は、ベース４６の中央にねじ孔４７が鉛直に形成され、ねじ孔４７の上端４７Ａに連通する嵌合孔４８が形成され、この嵌合孔４８がベース４６の上端４６Ａに開口されている。
ねじ孔４７にはストッパ４９がねじ込まれ、ベース４６の上端４６Ａにはロック部材５０のねじ部５１が水平状態にねじ結合されることにより、ねじ部５１の先端５１Ａが嵌合孔４８に突出可能とされている。
【００２６】
評価用軸部材４１は、図１に示す軸１２と同様に形成された部材であり、外径がベース４６の嵌合孔４８に嵌合可能に形成され、一定間隔をおいて一対の環状溝４２，４３が形成されている。
評価用軸部材４１を、ベース４６の嵌合孔４８に嵌め込むことにより、ストッパ４９の上端４９Ａに当接する。この状態で、ロック部材５０を締めてねじ部５１の先端５１Ａを評価用軸部材４１に当接することにより、評価用軸部材４１を測定位置にロックする。
【００２７】
また、評価用軸部材４１には、評価用軸部材４１に抜差し自在な抜差し軸受５５が嵌め込まれている。抜差し軸受５５は、評価用軸部材４１に抜差し自在に嵌め込まれた内輪５７と、ばね座５８を備えた外輪５６と、内輪５７と外輪５６との間に配置された複数個の転動体５９Ａと、複数個の転動体５９Ａを保持する保持器５９Ｂとを備える。
【００２８】
評価用軸受部６０は、ばね座６２を備えた外輪６１と、この外輪６１と環状溝４３との間に配置される複数個の転動体６３と、複数個の転動体６３を保持する保持器６４とを備える。
この評価用軸受部６０の外輪６１に備えたばね座６２と、抜差し軸受５５の外輪５６に備えたばね座５８との間にコイルばね３５が介装される。
【００２９】
測定手段６５は、一例として電気マイクロメータが該当する。この電気マイクロメータは本体６６が図示せぬ支え部材に取り付けられ、接触子６７が評価用軸受部６０を構成する外輪６１の開放端面６１Ａに接触されている。
【００３０】
このように構成されたコイルばねの評価冶具４０によれば、評価用軸部材４１を支持する支持手段４５を有し、評価用軸部材４１に同軸配置された抜差し軸受５５および評価用軸受部６０を有し、例えば評価用軸受部６０の外輪６１の周振れを測定する測定手段６５とを有するだけなので、コイルばねの評価冶具４０を簡単な構成にできる。
【００３１】
つぎに、コイルばね３５の製造方法について説明する。
先ず、コイルばねの評価冶具４０の評価用軸部材４１に同軸配置された抜差し軸受５５および評価用軸受部６０間にコイルばね３５を介装する。
つぎに、抜差し軸受５５および評価用軸受部６０を相対的に近接させることにより実使用条件長さＬとなるようにコイルばね３５を圧縮する。
つづいて、測定手段６５の接触子６７を外輪６１の開放端面６１Ａに接触する。
【００３２】
この状態で、評価用軸受部６０の外輪６１を回転させながら外輪６１のうちの抜差し軸受５５から離れた方向を向く開放端面６１Ａの周振れを測定手段６５で測定する。
周振れを測定した後、測定手段６５の測定値に基づいてコイルばね３５の自由状態における巻き端位置を調整する。これにより、軸受装置１０の軸１２に沿って同軸配置された第１軸受部１５および第２軸受部２５間に介装されて予圧を付与するコイルばね３５の製造が完了する。
【００３３】
このように、コイルばねの製造方法によれば、抜差し軸受５５および評価用軸受部６０間にコイルばね３５を介装した後、コイルばね３５を実使用条件下の長さＬとなるように圧縮し、評価用軸受部６０の外輪５６，６１を回転させながら外輪６１の周振れを測定手段６５で測定し、この測定値に基づいてコイルばね３５の自由状態における巻き端位置３６（図３参照）を調整できる。
よって、コイルばね３５の自由状態における巻き端位置３６の調整を簡単に確実におこなうことができる。
【００３４】
つぎに、図３〜図４に基づいてコイルばね３５について説明する。なお、このコイルばね３５は、図１に示すコイルばね３５とは有効巻き数が異なるだけでその他の構成は同じである。
図３に示すコイルばね３５は、有効巻き数が２巻きの例で、コイルばね３５の自由状態における巻き端３６の位置（巻き端位置）Ｐ１が、０．５巻き位置Ｐ２よりも巻軸３７の巻軸方向内側に配置されている。
具体的には、巻き端位置Ｐ１が０．５巻き位置Ｐ２よりもコイルばね３５の線径３８の線径寸法Ｄ１の３０％〜１２０％巻軸方向内側に配置されている。
【００３５】
このように、コイルばね３５の巻き端位置Ｐ１を設定することで、このコイルばね３５を実際に使用する状態、実使用長さＬに圧縮した際に、図４に示すようにコイルばね３５の両端３５Ａ，３５Ｂが巻軸３７に対して直交する面になる。
よって、図１に示す軸受装置１０の第１軸受部１５および第２軸受部２５間にコイルばね３５を介装し、このコイルばね３５で第１、第２軸受部１５，２５のそれぞれの外輪１６，２６に偏荷重をかけないようにできる。
加えて、従来技術のように、座巻き部を研削することで巻軸３７に対する座巻き部の直角度を保つ必要がないので、研削工程を省くことができ。
【００３６】
つぎに、コイルばね３５の変形例としてコイルばね７０を図５〜図６に基づいて説明する。
図５に示すコイルばね７０は、コイル有効巻き数が２．５巻きの例で、コイルばね７０の自由状態における巻き端７１の位置（巻き端位置）Ｐ３が、０．５巻き位置Ｐ４よりも巻軸７２の巻軸方向内側に配置されている。
具体的には、巻き端位置Ｐ３が、０．５巻き位置Ｐ４よりもコイルばね７０の線径７３の線径寸法Ｄ２の３０％〜１２０％巻軸方向内側に配置されている。
【００３７】
このように、コイルばね７０の巻き端位置Ｐ３を設定することで、このコイルばね７０を実際に使用する状態に圧縮すると、図６に示すようにコイルばね７０の両端７０Ａ，７０Ｂが巻軸７２に対して直交する面になる。
このように形成されたコイルばね７０を、図１に示すように軸受装置１０に組み込んだ際に、図３〜図４に示すコイルばね３５と同様に、第１軸受部１５の外輪１６と第２軸受部２５の外輪２６とに偏荷重をかけないようにできる。
【００３８】
つぎに、図７に基づいて第２実施形態について説明する。
図７に示すように、第２実施形態第１実施形態の軸受装置８０は、一例としてＶＴＲやテープストリーマ用のドラムスピンドルモータ（図示せず）の軸１２に沿って同軸配置された第１軸受部１５および第２軸受部２５を有し、第１軸受部１５の内輪軌道１３が軸１２の外周に形成されているとともに、第２軸受部２５の内輪軌道２７が軸１２の外周に形成され、かつ、第１軸受部１５および第２軸受部２５間に予圧を付与するためのコイルばね８２が介装されている。
すなわち、第２実施形態の軸受装置８０は、第１実施形態の軸受装置１０とはコイルばね３５，８２が異なるだけでその他の構成は第１実施形態と同じである。
【００３９】
第２実施形態によれば、第１実施形態と同様の効果を得ることができる。加えて、第２実施形態によれば、コイルばね８２を、中央８３が拡径した太鼓状の異径ばねとすることで、コイルばね８２を圧縮したときに、ストレート状のコイルばね３５，７０と比較して線径８４が重ならない。このため、密着長を短くでき、第２軸受部２５の組付けを容易にできる。
【００４０】
なお、前記実施形態では、軸受装置１０を、ＶＴＲやテープストリーマ用のドラムスピンドルモータの軸１２に適用する例について説明したが、これに限らないで、例えばＬＢＰ用モータやＨＤＤモータなどのディスクメモリスピンドルモータ、ＨＤＤのスイングアームの回転支持部やその他のモータに組み込むことも可能である。
【００４１】
また、前記実施形態では、コイルばねの評価冶具４０で外輪の周振れを測定手段６５で測定する際に、評価用軸受部６０の外輪６１の周振れを測定する例について説明したが、これに限らないで、抜差し軸受５５の外輪５６の周振れを測定しても同様の効果を得ることができる。
また、周振れの測定個所は開放端面６１Ａに限らず、コイルばねが設けられた側の内方端面６１Ｂ（図２参照）であってもよい。
【００４２】
また、前記実施形態では、両巻き端位置を０．５巻き位置よりも巻軸方向内側に配置したが、一方の巻き端位置のみがこのように構成されていてもよい。
さらに、本発明は、前述した各実施形態に限定されるものでなく、適宜な変形，改良等が可能であり、前述した各実施形態において例示した軸，第１軸受部，第２軸受部，コイルばね等の材質，形状，寸法，形態，数，配置個所，厚さ寸法等は本発明を達成できるものであれば任意であり、限定されない。
【００４３】
【発明の効果】
以上、説明したように、本発明によれば、請求項１に記載したように、コイルばねの自由状態における巻き端位置を、０．５巻き位置よりも巻軸方向内側に配置することで、第１、第２軸受部の外輪にコイルばねで偏荷重をかけないようにできる。
よって、第１、第２軸受部の外輪を巻軸に対して傾かないようにセットできるので、第１、第２軸受部をＶＴＲなどのハウジングに組み込む際に引っかかりが生じ難い。これにより、第１、第２軸受部をハウジングに手間をかけないで容易に組み込むことができる。
【００４４】
また、第１、第２軸受部の外輪がハウジングに組み込まれた際に、軸芯に対するハウジングの振れまわりを抑えることができるので、テープの案内を規格範囲に確実に入るようにできる。
さらに、座巻き部を研削して巻軸に対する座巻き部の直角度を保つ必要がないので、研削工程を省くことができ、コイルばねのコスト低減を図ることが可能になる。
【００４５】
また、請求項２に記載したように、巻き端位置を、０．５巻き位置よりもコイルばねの線径寸法の３０％〜１２０％巻軸方向内側に配置することで、第１、第２軸受部の外輪にコイルばねでより確実に偏荷重をかけないようにできる。
よって、第１、第２軸受部の外輪を軸芯に対して傾かないようにセットできるので、第１、第２軸受部をＶＴＲなどのハウジングに組み込む際に、より確実に引っかかりが生じ難くできる。これにより、第１、第２軸受部をハウジングに手間をかけないで容易に組み込むことができる。
【００４６】
また、第１、第２軸受部の外輪がハウジングに組み込まれた際に、軸芯に対するハウジングの振れまわりをより確実に抑えることができるので、テープの案内を規格範囲に確実に入るようにできる。
【００４７】
また、請求項３に記載したように、評価用第１、第２軸受部間にコイルばねを介装した後、コイルばねを実使用条件下となるように圧縮し、評価用第１、２の軸受部の外輪を回転させながら外輪の周振れを測定し、この測定値に基づいてコイルばねの自由状態における巻き端位置を調整できる。
従って、コイルばねの自由状態における巻き端位置の調整を簡単に確実におこなうことができ、作業工程にかける時間を短くできる。
【００４８】
また、請求項４に記載したように、評価用軸部材を支持する支持手段を有し、評価用軸部材に同軸配置された評価用第１、第２の軸受部を有し、評価用第１、第２の軸受部の外輪のうちの一方の周振れを測定する測定手段とを有するだけなので、コイルばねの評価冶具を簡単な構成にでき、設備費を抑えることができる。
【図面の簡単な説明】
【図１】本発明に係る軸受装置の第１実施形態を示す断面図である。
【図２】本発明に係るコイルばねの評価冶具を示す断面図である。
【図３】本発明に係るコイルばねの自由状態を示す側面図である。
【図４】本発明に係るコイルばねの実使用状態を示す側面図である。
【図５】本発明に係るコイルばね（変形例）の自由状態を示す側面図である。
【図６】本発明に係るコイルばね（変形例）の実使用状態を示す側面図である。
【図７】本発明に係る軸受装置の第２実施形態を示す断面図である。
【符号の説明】
１０，８０　　軸受装置
１２　軸
１５　第１軸受部
２５　第２軸受部
３２　嵌合部位
３５，７０，８２　コイルばね
３６，７１　　巻き端
３７，７２　　巻軸
３８，７３　　線径
４０　コイルばねの評価冶具
４１　評価用軸部材
４５　支持手段
５５　抜差し軸受（評価用第１軸受部）
５６，６１　　外輪
６０　評価用軸受部（評価用第２軸受部）
６１Ａ　　開放端面
６５　測定手段
Ｄ１，Ｄ２　　線径寸法
Ｐ１，Ｐ３　　巻き端位置
Ｐ２，Ｐ４　　０．５巻き位置[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a drum spindle motor for, for example, a VTR or tape streamer, a disk memory spindle motor such as an LBP motor or an HDD motor, a bearing device incorporated in a rotary support of a swing arm of an HDD, and other motors. The present invention relates to a method for manufacturing a coil spring to be incorporated in a device and an evaluation jig for the coil spring.
[0002]
[Prior art]
2. Description of the Related Art A bearing device is used in a VTR or a drum spindle motor for a tape streamer to support a spindle (hereinafter, referred to as a "shaft"). As this bearing device, for example, Japanese Unexamined Utility Model Publication No. 4-82425, "Rolling Bearing Device" is known.
[0003]
In the bearing device of this publication, as an example, a first bearing portion and a second bearing portion are provided at predetermined intervals on a shaft of a spindle motor, and a coil spring is interposed between the first bearing portion and the second bearing portion, The coil spring applies a preload to the outer ring of the first bearing and the outer ring of the second bearing.
In addition, each outer ring of the first bearing portion and the second bearing portion is incorporated in, for example, a housing.
[0004]
[Problems to be solved by the invention]
By the way, when a preload is applied to the outer ring of the first bearing portion and the outer ring of the second bearing portion by the coil spring of the above publication, an offset load is applied to each of the outer rings of the first and second bearing portions. It is conceivable that it will be inclined with respect to the axis.
[0005]
If the inclination of each outer ring is large, when the first and second bearing portions are incorporated into a high-precision housing such as a VTR, the outer ring may be caught and may damage the raceway surface of the outer ring, such as brinelling. If the bearing ring is damaged, a noise is generated, which is not preferable as a bearing device.
For this reason, it is necessary to incorporate the first and second bearing portions into the housing so as not to damage the raceway surface of the outer ring such as brinelling, and it takes time to incorporate the first and second bearing portions.
[0006]
Further, if the first and second bearing portions are fixed to the housing without correcting the inclination of the outer ring, the whirling of the housing with respect to the axis becomes large, and there is a possibility that the guide of the tape does not fall within the standard range. is there.
[0007]
In order to solve this problem, a method has been adopted in which the end turn portion of the coil spring is ground so that the end turn portion keeps a right angle with respect to the axis. This hindered cost reduction of the spring.
[0008]
In addition, even if the coil spring is set between the outer races of the first and second bearings, the coil spring is installed between the outer races of the first and second bearings even if the right angle of the end turns is obtained before the coil spring is assembled between the outer races of the first and second bearings. When the spring is compressed, the end turns are not square.
For this reason, it is conceivable that an unbalanced load is applied to each of the outer rings of the first and second bearing portions, and these outer rings are inclined with respect to the axis.
[0009]
Therefore, as described above, there is a possibility that a trouble that it takes time to assemble the first and second bearing portions and a problem that the whirling of the housing becomes large with respect to the shaft center may occur.
[0010]
The present invention has been made in view of the above-described problems, and an object of the present invention is to reduce the inclination of each of the outer rings of the first and second bearings and to compare the first and second bearings with the housing. It is an object of the present invention to provide a bearing device, a method for manufacturing a coil spring, and a jig for evaluating a coil spring which can be easily assembled.
[0011]
[Means for Solving the Problems]
In order to achieve the above-mentioned object, the present invention has a first bearing portion and a second bearing portion coaxially arranged along an axis, as described in claim 1, wherein the first bearing portion and the second bearing portion have the same configuration. A bearing device in which a coil spring for applying a preload is interposed between second bearing portions, wherein a winding end position of the coil spring in a free state is disposed on the inner side in the winding direction than a 0.5 winding position. It is characterized by having been done.
[0012]
In the bearing device configured as described above, the winding end position in the free state of the coil spring is arranged on the inner side in the winding axis direction with respect to the 0.5 winding position, so that the coil is disposed on the outer ring of the first and second bearing portions. An unbalanced load can be prevented from being applied by a spring.
Therefore, the outer rings of the first and second bearings can be set so as not to be inclined with respect to the axis, so that the first and second bearings are less likely to be caught when incorporated in a housing such as a VTR.
[0013]
Further, when the outer races of the first and second bearing portions are incorporated into the housing, the whirling of the housing with respect to the axis can be suppressed.
Further, by grinding the end winding portion, it is not necessary to maintain the perpendicularity of the end winding portion with respect to the axis, and the grinding step can be omitted.
[0014]
Further, in the present invention, as described in claim 2, the winding end position is disposed 30% to 120% of the wire diameter of the coil spring inward in the winding axis direction than the 0.5 winding position. It is characterized by having.
[0015]
By disposing the winding end position 30% to 120% of the wire diameter dimension of the coil spring in the winding axis direction more than the 0.5 winding position, the outer rings of the first and second bearing portions are more reliably provided by the coil spring. Unbalanced load can be prevented.
Therefore, since the outer races of the first and second bearings can be set so as not to be inclined with respect to the axis, when the first and second bearings are incorporated in a housing such as a VTR, they can be more reliably prevented from being caught. .
[0016]
Further, when the outer races of the first and second bearings are assembled into the housing, the whirling of the housing with respect to the axis can be suppressed more reliably.
[0017]
Further, in the present invention, as described in claim 3, manufacturing of a coil spring interposed between the first bearing portion and the second bearing portion coaxially arranged along the axis of the bearing device to apply a preload. A method, comprising: interposing the coil spring between an evaluation first bearing portion and an evaluation second bearing portion coaxially arranged on an evaluation shaft member, and further comprising the evaluation first bearing portion and the evaluation second bearing portion. Each of the outer rings is compressed by bringing the bearing portions relatively close to each other so that the coil spring is compressed so that the actual use condition is achieved, and the outer ring of the first bearing portion for evaluation and the outer ring of the second bearing portion for evaluation are rotated. And measuring the circumferential runout of the end face of one of the coil springs by a measuring means, and adjusting the winding end position in the free state of the coil spring based on the measurement value of the measuring means.
[0018]
In the manufacturing method of the coil spring configured as described above, after the coil spring is interposed between the first and second bearing portions for evaluation, the coil spring is compressed so as to be under actual use conditions, The circumferential runout of the outer ring is measured while rotating the outer ring of the first and second bearings, and the winding end position in the free state of the coil spring can be adjusted based on the measured value.
Therefore, it is possible to easily and reliably adjust the winding end position in the free state of the coil spring.
[0019]
Further, in the present invention, as described in claim 4, evaluation of a coil spring interposed between the first bearing portion and the second bearing portion coaxially arranged along the axis of the bearing device and applying a preload. A jig, an evaluation shaft member, support means for supporting the evaluation shaft member, an evaluation first bearing portion and an evaluation second bearing portion coaxially arranged on the evaluation shaft member; Measuring means for measuring the circumferential runout of the end face of one of the outer races of the first bearing portion for evaluation and the second bearing portion for evaluation, between the first bearing portion for evaluation and the second bearing portion for evaluation. The coil spring is interposed, and the coil spring is compressed so that the first bearing portion for evaluation and the second bearing portion for evaluation are relatively close to each other so that the actual use condition is obtained. While rotating, measure the circumferential runout by the measuring means. Characterized in that it.
[0020]
In the jig of the coil spring thus configured, the jig has a support means for supporting the shaft member for evaluation, and has first and second bearing portions for evaluation coaxially arranged on the shaft member for evaluation. Since only the measuring means for measuring the circumferential runout of one of the outer rings of the first and second bearing portions for evaluation is provided, the evaluation jig for the coil spring can be made simple.
[0021]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, embodiments according to the present invention will be described in detail with reference to the drawings. In addition, in each embodiment described below, the members and the like already described in FIGS. 1 to 6 are denoted by the same reference numerals or corresponding reference numerals in the drawings to simplify or omit the description.
[0022]
As shown in FIG. 1, a bearing device 10 according to a first embodiment includes, as an example, a first bearing coaxially arranged along a shaft 12 of a drum spindle motor (not shown) for a VTR or a tape streamer. The first and second bearing portions 15 and 25 have inner raceways 13 and 14 formed on the outer periphery of the shaft 12 at regular intervals. A coil spring 35 for applying a preload is interposed between the second bearing portions 25.
The coil spring 35 is interposed between the first spring seat 17 provided on the outer race 16 of the first bearing 15 and the second spring seat 27 provided on the outer race 26 of the second bearing 25.
[0023]
In the first bearing portion 15, a plurality of rolling elements 18 are arranged between the outer ring 16 and the inner ring track 13, and the plurality of rolling elements 18 are held by a retainer 19.
In the second bearing portion 25, a plurality of rolling elements 28 are arranged between the outer ring 26 and the inner ring track 14, and the plurality of rolling elements 28 are held by a retainer 29.
Hereinafter, the evaluation jig 40 for evaluating the shape of the coil spring 35 will be described.
[0024]
As shown in FIG. 2, the evaluation jig 40 of the coil spring includes an evaluation shaft member 41, a support means 45 for supporting the evaluation shaft member 41, and an insertion / removal bearing (evaluation shaft) coaxially arranged on the evaluation shaft member 41. Peripheral runout of the open end face 61A of the outer bearing 61 of the first bearing portion 55, the evaluation bearing portion (second evaluation bearing portion) 60, and the outer ring 61 of the second evaluation bearing portion 60 facing away from the insertion bearing 55. And measuring means 65 capable of measuring
[0025]
The support means 45 has a screw hole 47 formed vertically in the center of the base 46, a fitting hole 48 communicating with the upper end 47A of the screw hole 47, and this fitting hole 48 is opened at the upper end 46A of the base 46. ing.
A stopper 49 is screwed into the screw hole 47, and a screw portion 51 of the lock member 50 is screwed to the upper end 46A of the base 46 in a horizontal state, so that the tip end 51A of the screw portion 51 can protrude into the fitting hole 48. It has been.
[0026]
The evaluation shaft member 41 is a member formed in the same manner as the shaft 12 shown in FIG. 1, has an outer diameter formed so as to be able to be fitted in the fitting hole 48 of the base 46, and has a pair of annular grooves provided at regular intervals. 42 and 43 are formed.
The evaluation shaft member 41 is brought into contact with the upper end 49 A of the stopper 49 by fitting into the fitting hole 48 of the base 46. In this state, the evaluation shaft member 41 is locked at the measurement position by tightening the lock member 50 and abutting the distal end 51A of the screw portion 51 against the evaluation shaft member 41.
[0027]
Further, an insertion / removal bearing 55 that can be inserted into and removed from the evaluation shaft member 41 is fitted into the evaluation shaft member 41. The insertion / removal bearing 55 includes an inner ring 57 that is removably fitted into the evaluation shaft member 41, an outer ring 56 having a spring seat 58, and a plurality of rolling elements 59A disposed between the inner ring 57 and the outer ring 56. , A retainer 59B for holding a plurality of rolling elements 59A.
[0028]
The evaluation bearing portion 60 includes an outer ring 61 having a spring seat 62, a plurality of rolling elements 63 disposed between the outer ring 61 and the annular groove 43, and a retainer holding the plurality of rolling elements 63. 64.
The coil spring 35 is interposed between a spring seat 62 provided on the outer ring 61 of the evaluation bearing portion 60 and a spring seat 58 provided on the outer ring 56 of the insertion / removal bearing 55.
[0029]
As an example, the measuring unit 65 corresponds to an electric micrometer. In this electric micrometer, a main body 66 is attached to a support member (not shown), and a contact 67 is in contact with an open end face 61A of an outer ring 61 constituting a bearing 60 for evaluation.
[0030]
According to the coil spring evaluation jig 40 configured as described above, the insertion / removal bearing 55 and the evaluation bearing portion 60 having the support means 45 for supporting the evaluation shaft member 41 and being coaxially arranged on the evaluation shaft member 41 are provided. , For example, only the measuring means 65 for measuring the circumferential runout of the outer race 61 of the bearing portion 60 for evaluation, so that the evaluation jig 40 for the coil spring can have a simple configuration.
[0031]
Next, a method for manufacturing the coil spring 35 will be described.
First, the coil spring 35 is interposed between the insertion / removal bearing 55 and the evaluation bearing portion 60 coaxially arranged on the evaluation shaft member 41 of the coil spring evaluation jig 40.
Next, the coil spring 35 is compressed so as to have the actual use condition length L by bringing the insertion / removal bearing 55 and the evaluation bearing portion 60 relatively close to each other.
Subsequently, the contact 67 of the measuring means 65 contacts the open end face 61A of the outer race 61.
[0032]
In this state, while rotating the outer ring 61 of the bearing portion for evaluation 60, the measuring means 65 measures the circumferential runout of the open end face 61A of the outer ring 61 which faces away from the insertion / removal bearing 55.
After measuring the circumferential runout, the winding end position of the coil spring 35 in the free state is adjusted based on the measurement value of the measuring means 65. Thereby, the manufacture of the coil spring 35 interposed between the first bearing portion 15 and the second bearing portion 25 coaxially arranged along the shaft 12 of the bearing device 10 and applying a preload is completed.
[0033]
As described above, according to the coil spring manufacturing method, after the coil spring 35 is interposed between the insertion / removal bearing 55 and the evaluation bearing portion 60, the coil spring 35 is compressed to have the length L under actual use conditions. Then, while rotating the outer rings 56, 61 of the evaluation bearing portion 60, the circumferential runout of the outer ring 61 is measured by the measuring means 65, and based on the measured value, the winding end position 36 in the free state of the coil spring 35 (see FIG. 3). ) Can be adjusted.
Therefore, the winding end position 36 in the free state of the coil spring 35 can be easily and reliably adjusted.
[0034]
Next, the coil spring 35 will be described with reference to FIGS. The coil spring 35 has the same configuration as the coil spring 35 shown in FIG. 1 except for the number of effective windings.
The coil spring 35 shown in FIG. 3 is an example in which the effective number of windings is two. The position (winding end position) P1 of the winding end 36 in the free state of the coil spring 35 is larger than the winding shaft 37 by 0.5 winding position P2. Are arranged on the inner side in the winding axis direction.
More specifically, the winding end position P1 is disposed 30% to 120% of the wire diameter D1 of the wire diameter 38 of the coil spring 35 inside the winding axis direction than the 0.5 winding position P2.
[0035]
In this way, by setting the winding end position P1 of the coil spring 35, when the coil spring 35 is compressed to the actual use length L, as shown in FIG. Both ends 35 A and 35 B are surfaces orthogonal to the winding shaft 37.
Therefore, a coil spring 35 is interposed between the first bearing portion 15 and the second bearing portion 25 of the bearing device 10 shown in FIG. 1, and the respective outer rings of the first and second bearing portions 15 and 25 are provided by the coil spring 35. An unbalanced load can be prevented from being applied to 16, 26.
In addition, unlike the related art, grinding the end winding portion does not require maintaining the perpendicularity of the end winding portion with respect to the winding shaft 37, so that the grinding step can be omitted.
[0036]
Next, a coil spring 70 as a modification of the coil spring 35 will be described with reference to FIGS.
The coil spring 70 shown in FIG. 5 has an example in which the number of effective windings of the coil is 2.5. The position (winding end position) P3 of the winding end 71 in the free state of the coil spring 70 is larger than the 0.5 winding position P4. It is arranged inside the winding shaft 72 in the winding shaft direction.
Specifically, the winding end position P3 is arranged 30% to 120% of the wire diameter D2 of the wire diameter 73 of the coil spring 70 inside the winding axis direction than the 0.5 winding position P4.
[0037]
By setting the winding end position P3 of the coil spring 70 in this way, when the coil spring 70 is compressed to a state where it is actually used, both ends 70A and 70B of the coil spring 70 are connected to the winding shaft 72 as shown in FIG. Is a plane orthogonal to.
When the thus formed coil spring 70 is incorporated into the bearing device 10 as shown in FIG. 1, similarly to the coil spring 35 shown in FIGS. (2) An unbalanced load can be prevented from being applied to the outer ring 26 of the bearing 25.
[0038]
Next, a second embodiment will be described with reference to FIG.
As shown in FIG. 7, a bearing device 80 according to the second embodiment has a first bearing coaxially arranged along a shaft 12 of a drum spindle motor (not shown) for a VTR or a tape streamer. The first bearing portion 15 has an inner raceway 13 formed on the outer periphery of the shaft 12, and the second bearing portion 25 has an inner raceway 27 formed on the outer periphery of the shaft 12. Further, a coil spring 82 for applying a preload is interposed between the first bearing portion 15 and the second bearing portion 25.
That is, the bearing device 80 of the second embodiment is the same as the bearing device 10 of the first embodiment except that the coil springs 35 and 82 are different.
[0039]
According to the second embodiment, the same effects as those of the first embodiment can be obtained. In addition, according to the second embodiment, the coil spring 82 is a drum-shaped different-diameter spring whose center 83 is enlarged, so that when the coil spring 82 is compressed, the straight coil springs 35 and 70 are compressed. And the wire diameter 84 does not overlap. For this reason, the contact length can be shortened, and the second bearing portion 25 can be easily assembled.
[0040]
In the above-described embodiment, an example in which the bearing device 10 is applied to the shaft 12 of a drum spindle motor for a VTR or a tape streamer has been described. However, the present invention is not limited to this. For example, a disk memory such as an LBP motor or an HDD motor may be used. It is also possible to incorporate it into a spindle motor, a rotation support portion of a swing arm of an HDD, or another motor.
[0041]
In the above-described embodiment, an example in which the circumferential runout of the outer race 61 of the evaluation bearing unit 60 is measured when the circumferential runout of the outer race is measured by the coil spring evaluation jig 40 by the measuring unit 65 has been described. The same effect can be obtained by measuring the circumferential runout of the outer ring 56 of the insertion / removal bearing 55 without limitation.
Further, the measurement point of the circumferential runout is not limited to the open end face 61A, but may be the inner end face 61B (see FIG. 2) on the side where the coil spring is provided.
[0042]
Further, in the above-described embodiment, both winding end positions are arranged on the inner side in the winding axis direction than the 0.5 winding position, but only one winding end position may be configured in this manner.
Further, the present invention is not limited to the above-described embodiments, but can be appropriately modified, improved, and the like. The shaft, the first bearing portion, the second bearing portion, and the shaft illustrated in the above-described embodiments can be used. The material, shape, size, form, number, location, thickness, etc. of the coil spring and the like are arbitrary and not limited as long as the present invention can be achieved.
[0043]
【The invention's effect】
As described above, according to the present invention, as described in claim 1, by arranging the winding end position in the free state of the coil spring in the winding axis direction relative to the 0.5 winding position, An unbalanced load can be prevented from being applied to the outer rings of the first and second bearings by the coil spring.
Therefore, since the outer rings of the first and second bearings can be set so as not to be inclined with respect to the winding shaft, the first and second bearings are less likely to be caught when incorporated into a housing such as a VTR. Thus, the first and second bearing portions can be easily incorporated into the housing without trouble.
[0044]
Further, when the outer races of the first and second bearings are assembled into the housing, the whirling of the housing with respect to the shaft center can be suppressed, so that the tape guide can be surely brought into the standard range.
Further, since it is not necessary to grind the end winding portion to maintain the perpendicularity of the end winding portion with respect to the winding shaft, the grinding step can be omitted, and the cost of the coil spring can be reduced.
[0045]
Also, as described in claim 2, the first and second winding ends are arranged 30% to 120% of the wire diameter of the coil spring inward in the winding axis direction than the 0.5 winding position. The bias load can be more reliably prevented from being applied to the outer ring of the bearing portion by the coil spring.
Therefore, since the outer races of the first and second bearings can be set so as not to be inclined with respect to the axis, when the first and second bearings are incorporated in a housing such as a VTR, they can be more reliably prevented from being caught. . Thus, the first and second bearing portions can be easily incorporated into the housing without trouble.
[0046]
In addition, when the outer races of the first and second bearings are assembled into the housing, the whirling of the housing with respect to the axis can be suppressed more reliably, so that the tape guide can be surely brought into the standard range. .
[0047]
Further, as described in claim 3, after the coil spring is interposed between the first and second bearings for evaluation, the coil spring is compressed so as to be under actual use conditions, and the first and second evaluations are used. The circumferential runout of the outer ring is measured while rotating the outer ring of the bearing portion, and the winding end position in the free state of the coil spring can be adjusted based on the measured value.
Therefore, the adjustment of the winding end position in the free state of the coil spring can be easily and reliably performed, and the time required for the work process can be shortened.
[0048]
Further, as described in claim 4, it has a support means for supporting the shaft member for evaluation, and has first and second bearing portions for evaluation arranged coaxially on the shaft member for evaluation, Since there is only a measuring means for measuring the circumferential runout of one of the outer rings of the first and second bearing portions, the jig for evaluating the coil spring can be made simple and the equipment cost can be reduced.
[Brief description of the drawings]
FIG. 1 is a sectional view showing a first embodiment of a bearing device according to the present invention.
FIG. 2 is a sectional view showing a jig for evaluating a coil spring according to the present invention.
FIG. 3 is a side view showing a free state of the coil spring according to the present invention.
FIG. 4 is a side view showing an actual use state of the coil spring according to the present invention.
FIG. 5 is a side view showing a free state of a coil spring (modification) according to the present invention.
FIG. 6 is a side view showing an actual use state of a coil spring (modification) according to the present invention.
FIG. 7 is a sectional view showing a second embodiment of the bearing device according to the present invention.
[Explanation of symbols]
10, 80 Bearing device 12 Shaft 15 First bearing portion 25 Second bearing portion 32 Fitting portion 35, 70, 82 Coil spring 36, 71 Winding end 37, 72 Winding shaft 38, 73 Wire diameter 40 Coil spring evaluation jig 41 Shaft member 45 for evaluation Supporting means 55 Removable bearing (first bearing part for evaluation)
56,61 Outer ring 60 Bearing part for evaluation (second bearing part for evaluation)
61A open end surface 65 measuring means D1, D2 wire diameter dimension P1, P3 winding end position P2, P4 0.5 winding position

Claims

A bearing device having a first bearing portion and a second bearing portion coaxially arranged along an axis, and a coil spring for applying a preload between the first bearing portion and the second bearing portion is interposed. So,
A bearing device, wherein a winding end position of the coil spring in a free state is disposed on the inner side in the winding axis direction than a 0.5 winding position.

2. The bearing device according to claim 1, wherein the winding end position is located 30% to 120% of a wire diameter dimension of the coil spring inward in the winding axis direction than the 0.5 winding position. 3.

A method of manufacturing a coil spring that is interposed between a first bearing portion and a second bearing portion coaxially arranged along an axis of a bearing device and applies a preload,
The coil spring is interposed between the first bearing for evaluation and the second bearing for evaluation coaxially arranged on the shaft member for evaluation, and the first bearing for evaluation and the second bearing for evaluation are relatively positioned. , The coil spring is compressed so as to be in a practical use condition,
While rotating the outer ring of the first bearing portion for evaluation and the outer ring of the second bearing portion for evaluation, the circumferential runout of one end surface of each of the outer rings is measured by measuring means, and based on the measurement value of the measuring means, A method of manufacturing a coil spring, comprising adjusting a winding end position of the coil spring in a free state.

An evaluation jig for a coil spring that is interposed between a first bearing portion and a second bearing portion coaxially arranged along an axis of a bearing device and applies a preload,
Evaluation shaft member, support means for supporting the evaluation shaft member, an evaluation first bearing portion and an evaluation second bearing portion coaxially arranged on the evaluation shaft member, and the evaluation first bearing portion And measuring means capable of measuring the peripheral runout of the end face of one of the outer rings of the second bearing portion for evaluation,
The actual use condition is obtained by interposing the coil spring between the first bearing portion for evaluation and the second bearing portion for evaluation, and bringing the first bearing portion for evaluation and the second bearing portion for evaluation relatively close to each other. Compress the coil spring so that it is below,
An evaluation jig for a coil spring, wherein the peripheral runout is measured by the measuring means while rotating each of the outer rings.