JP4367973B2

JP4367973B2 - Head feeding mechanism and optical pickup feeding mechanism

Info

Publication number: JP4367973B2
Application number: JP23100497A
Authority: JP
Inventors: 徹森川; 隆志井塚
Original assignee: Sony Corp
Current assignee: Sony Corp
Priority date: 1996-10-04
Filing date: 1997-08-27
Publication date: 2009-11-18
Anticipated expiration: 2017-08-27
Also published as: JPH10162522A

Description

【０００１】
【発明の属する技術分野】
本発明はヘッド送り機構並びに光学ピックアップの送り機構に関する。特に、本発明は、送りねじを用いるヘッド送り機構並びに光学ピックアップの送り機構に関する。
【０００２】
【従来の技術】
ディスク状記録媒体、例えば、光ディスクへの情報信号の記録又は光ディスクからの情報信号の読み出し、或は、これらの記録及び読み出しの双方を行うヘッドである光学ピックアップの送り機構に送りねじを用いたものがある。このような送り機構の一例を図８に示す。
【０００３】
送りねじａは螺軸部ｂと螺軸部ｂの一方の端部に連続したギヤ部ｃ及び受部ｄが一体的に形成されて成り、その軸方向に離間した２つの軸受に回転自在に支持されている。
【０００４】
送りねじａはギヤ部ｃ及び受部ｄが形成されていない側の螺軸部ｂの端部が図示しないスラスト軸受に支持され、螺軸部ｂの反対側の端部が軸受ｅに支持されている。ギヤ部ｃは図示しない中間ギヤを介してモータに連結されており、また、受部ｂは弾性体ｆと弾接され、これにより送りねじａは軸方向に図８に示すＦ２の力で押圧付勢されている。
【０００５】
軸受ｅは送りねじａを取り付けるために一方が開口されており、開口面側には軸受ｅからの送りねじａの脱落を防止するために押さえ部材ｇが取着されている。
【０００６】
送りねじａは螺軸部ｂが図示しない光学ピックアップのベース体に設けられた送りナット部と螺合され、モータの回転による送りねじａの回転に伴って光学ピックアップが光ディスクの半径方向に移動されるようになっている。
【０００７】
【発明が解決しようとする課題】
ところで、図８に示した送り機構にあっては、送りねじａと軸受ｅとの間に動作上必要な間隙Δｘ１、Δｘ２が設けられている。
【０００８】
これら間隙Δｘ１、Δｘ２により送りねじａの回転時に送りねじａが図８に示すＣ方向にがたついてしまい送りねじａと軸受ｅとの衝突に起因して振動が発生してしまう。かかる振動の発生が光学ピックアップに伝達されると光学ピックアップによる光ディスクに記録された信号の読取等に支障を来し、振動が大きなときにはトラックジャンプによる音飛びが発生してしまう虞がある。
【０００９】
上述した不具合を解消するために間隙Δｘ１、Δｘ２が極小になるように送りねじａと軸受ｅの寸法を定めることが考えられるが、このようにすると部品寸法管理が厳しく要求されコスト高になると共に送りねじａと軸受ｅの回転損失（負荷）が増大するという新たな問題が生じてしまう。
【００１０】
特に、上述したように、軸受ｅとその開口面側に設けられた押さえ部材ｇとが別部材で形成されていると、Δｘ１とΔｘ２を極小にすることは両者の寸法公差の発生により極めて困難である。
【００１１】
そこで、本発明ヘッド送り機構並びに光学ピックアップの送り機構は、上述した問題点を克服し、送りねじや軸受の部品寸法を変更しなくとも軸受内での送りねじのがたつきを防止しヘッドに伝達される振動の低減を図ることを課題とする。
【００１２】
【課題を解決するための手段】
本発明ヘッド送り機構は、上述した課題を解決するために、ヘッド機構と、先端部が半球状に形成され、ヘッド機構と係合し回転することによってヘッド機構を送る送りねじと、送りねじを回転させる回転駆動機構と、回転駆動機構が配置されると共に少なくとも一方がスラスト軸受として形成され送りねじを支持する一対の軸受部を有するベースと、ベースに設けられると共に、送りねじの先端部と当接し送りねじをスラスト方向とスラスト方向に直交する方向とに付勢する弾性部材とを備え、弾性部材は、基端部と当接部とが屈曲した弾性変位部によってほぼＵ字状となるように形成され、基端部には、弾性部材の内方に向かって突出し、当接部が送りねじの先端部と当接した際に当接部と当接して当接部の送りねじの軸方向の移動量を規制する突起が形成され、突起は、弾性部材の内方に向かって突出すると共に、上側部と該上側部より突出量の大きい下側部とを有する階段状に形成され、弾性部材の当接部が送りねじの先端部によってスラスト方向に押圧されたとき、階段状に形成された突起によって、当接部の送りねじとの当接面が斜め方向を向くようにしたものである。
【００１３】
また、本発明光学ピックアップの送り機構は、上述した課題を解決するために、光学ピックアップが設けられたピックアップベースと、ピックアップベースをガイドするガイド機構と、先端部が半球状に形成され、ピックアップベースと係合し回転することによってピックアップベースをガイド機構に沿って送る送りねじと、送りねじを回転させる回転駆動機構と、回転駆動機構が配置されると共に少なくとも一方がスラスト軸受として形成され送りねじを支持する一対の軸受部を有するベースと、ベースに設けられると共に、送りねじの先端部と当接し送りねじをスラスト方向とスラスト方向に直交する方向とに付勢する弾性部材とを備え、弾性部材は、基端部と当接部とが屈曲した弾性変位部によってほぼＵ字状となるように形成され、基端部には、弾性部材の内方に向かって突出し、当接部が送りねじの先端部と当接した際に当接部と当接して当接部の送りねじの軸方向の移動量を規制する突起が形成され、突起は、弾性部材の内方に向かって突出すると共に、上側部と該上側部より突出量の大きい下側部とを有する階段状に形成され、弾性部材の当接部が送りねじの先端部によってスラスト方向に押圧されたとき、階段状に形成された突起によって、当接部の送りねじとの当接面が斜め方向を向くようにしたものである。
【００１４】
従って、本発明にあっては、送りねじの先端部と当接し送りねじをスラスト方向とスラスト方向に直交する方向とに付勢する弾性部材を備えたので、簡単な構成によりヘッドの送り動作の際の振動を抑制することができる。また、送りねじの先端部が半球状に形成されていて、当接片は送りねじの先端部とほぼ点接触する状態になるので、当接片と先端部とが当接した状態で送りねじが回転されることによって生じる摩擦も小さくすることができる。このようにして、送りねじや軸受の部品寸法を変更しなくても、軸受内での送りねじのがたつきが防止される。
【００１５】
【発明の実施の形態】
以下、図面を用いて本発明に係るヘッド送り機構について説明する。以下に述べる本発明の各実施の形態では、記録媒体として所謂コンパクトディスクのような再生専用型の光ディスク（以下、単に「光ディスク」という。）を用いる光ディスク再生装置に用いられる光学ピックアップの送り機構を例に挙げて説明する。
【００１６】
図１に示すように、第１の実施の形態に係る光学ピックアップの送り機構は、合成樹脂から形成されたベース１を有する。ベース１には、開口部２と取り付け用開口部３とが形成されている。開口部２は、光ディスク２５の径方向に沿って長方形状に形成されており、後述する光学ピックアップが開口部２内を光ディスク２５の径方向に移動する。取り付け用開口部３は、ほぼ円形状に形成されており、図示しないスピンドルモータが取り付けられる。
【００１７】
取り付け用開口部３に取り付けられたスピンドルモータの回転軸の先端側には光ディスク２５が載置されるディスクテーブル２４が取り付けられている。ディスクテーブル２４に載置された光ディスク２５は、例えば、線速度一定で回転駆動される。開口部２は少なくとも後述する光学ピックアップによって光ディスク２５の信号記録領域の全面が走査するに足りる大きさに形成されている。
【００１８】
光学ピックアップ２０は、対物レンズ２１、対物レンズ２１をフォーカシング方向及びトラッキング方向に駆動するための図示しないアクチュエータ、光源としての図示しない半導体レーザ、図示しない光検出器及び図示しない光学系及びアクチュエータ、半導体レーザ、光検出器及び光学系が設けられる送りベース２０ａを有する。
【００１９】
対物レンズ２１は、光学ピックアップ２０が後述する送り機構によって光ディスク２５の径方向に送られた際に、光ディスク２５の直径を通る直線上と一致する移動軌跡を描くように送りベース２０ａに配されている。送りベース２０ａには、後述する送りねじと係合するナット部２２と後述するガイド部と係合する係合爪２３が設けられている。係合爪２３は、後述する送りねじが挿通される挿通孔が各々形成された一対の突出片２０ｂと２０ｂとの間に配されている。
【００２０】
ベース１には、開口部２に配される光学ピックアップ２０を挟んで一方の側に一対の軸受部４、５が設けられおり、他方の側にはガイド部６が設けられている。
【００２１】
一対の軸受部４、５のうちの一方の軸受部４は、図５に示すように、断面が例えば図１で見た紙面の奥側に向かって開放され、上側半分が曲面部４ａとなるほぼＵ字状になるように形成されている。他方の軸受部５は、開口部２の内方に向かって開放したスラスト軸受部として形成されている。ガイド部６には、送りベース２０ａの係合爪２３が係合する。
【００２２】
図１及び図２に示すように、ベース１から突出するように形成された取り付け部７には、送りねじの回転駆動機構としての送り機構を構成する送りモータ８、駆動ギヤ８ａや、中間ギヤ９が配されている。送りモータ８は、回転軸が後述する送りねじとほぼ平行になるように取り付け部７に配されている。送りモータ８の回転軸には駆動ギヤ８ａが取り付けられており、駆動ギヤ８ａは中間ギヤ９と噛み合っている。中間ギヤ９は、中間ギヤ９の回転軸が取り付け部７に回転自在に取り付けられている。
【００２３】
尚、ベース１には、図１に示すように、ベース１より外方に向かって突出する複数の突出片１ａ、１ｂが設けられている。これらの突出片１ａ、１ｂは、図示しない再生装置のシャーシに必要に応じてダンパを介して各々取り付けられる。図１には、図面の関係で突出片は２つしか図示されていないが、実際には３つの突出片がベース１に形成されている。
【００２４】
図１に示すように、送りねじ１０はほぼ全体にわたって形成されたねじ部１３を有するとともに一端側にギヤ部１２、突起部１１が設けられている。ねじ部１３と突起部１１は一体的に形成されており、ギヤ１２が後から送りねじ１０に嵌入されることによって形成されている。突起部１１は、図１及び図２に示すように、送りねじ１０のねじ部１２よりも突出し、且つ、先端部１１ａが半球状になるように形成されている。突起部１１の先端部１１ａが後述する付勢部と当接する。
【００２５】
送りねじ１０は、光学ピックアップ２０を挟んでベース１のガイド部６が設けられている側と反対側で、且つ、開口部２を亘るように一端が軸受部４によって軸支されているとともに他端がスラスト軸受部としての軸受部５によって軸支されている。送りねじ１０は、送りベース２０ａの一対の突出片２０ｂ、２０ｂの挿通孔に挿通されるとともに、ねじ部１３と送りベース２０ａのナット部２２が噛み合っている。
【００２６】
送りねじ１０のギヤ部１２は、上述した中間ギヤ９と噛み合っている。その結果、送りねじ１０には送りモータ８の回転力が駆動ギヤ８ａ、中間ギヤ９を介して伝達され、送りねじ１０が回転される。送りねじ１０と光学ピックアップ２０のナット部２２が噛み合っているので、送りねじ１０が回転されることによって光学ピックアップ２０がガイド部６に沿って光ディスク２５の径方向に移動される。その結果、対物レンズ２１から光ディスク２５に照射された光ビームが光ディスク２５を走査して光ディスク２５に記録されているデータが読み出される。
【００２７】
図１及び図２に示すように、送りねじ１０を回転駆動する送りモータ８、駆動ギヤ８ａ、中間ギヤ９の一方の面側を覆うようにベース１に押さえ部材１４が取り付けられる。押さえ部材１４は、図３に示すように、送りモータ８、駆動ギヤ８ａ、中間ギヤ９の一方の面側を覆うに足りる大きさに形成された板状部１４ａに係合片１４ｂ、ねじ挿通孔１４ｃ、付勢部１５が合成樹脂材料を用いて一体に形成されている。
【００２８】
係合片１４ｂは板状部１４ａより突出するように形成されており、先端部分にベース１に形成された図示しない係合孔と係合する係合爪１４ｄが形成されている。この係合爪１４ｄがベース１の係合孔と係合した状態でねじ挿通孔１４ｃにねじが挿通され、このねじがベース１の図示しないねじ取り付け孔と係合することによって押さえ部材１４がベース１に送りモータ８、駆動ギヤ８ａ、中間ギヤ９の一方の面側を覆うように取り付けられる。
【００２９】
押さえ部材１４に形成された付勢部１５は、図１及び図２に示すように、押さえ部材１４がベース１に取り付けられた状態で送りねじ１０の突起部１１の先端部１１ａと当接する。
【００３０】
付勢部１５は、基端部１６と当接部（当接片）１７とが屈曲した弾性変位部１８によってほぼＵ字状となるように形成されている。基端部１６には、付勢部１５の内方に向かって突出する突起１９が形成されている。突起１９は、当接部１７が送りねじ１０の突起部１１の先端部１１ａと当接した際に当接片１７と当接して当接片１７の送りねじ１０の軸方向の移動量を規制するとともに、図４に示すように、送りねじ１０に付勢力を印加するためのものである。
【００３１】
突起１９は、図３及び図４に示すように、付勢部１５の内方に向かって突出する階段状に形成され、上側部１９ａと上側部１９ａよりも突出量の大きい下側部１９ｂとを有する。送りねじ１０の先端部１１ａが上述したように半球状に形成されていることによって当接片１７は送りねじ１０の先端部１１ａとほぼ点接触する状態になるため、当接片１７と先端部１１ａとが当接した状態で送りねじが１０が回転されることによって生じる損失をできるだけ小さくすることができる。
【００３２】
押さえ部材１４がベース１に取り付けられ、送りねじ１０の突起部１１の先端部１１ａと当接した際に、送りねじ１０に印加される付勢力について図４を用いて説明する。
【００３３】
上述したように、押さえ部材１４が係合片１４ｂの係合爪１４ｄをベースの係合孔に係合させ、ねじ挿通孔１４ｃを介してねじを押さえ部材１４に挿通し、ベース１にねじ止めすることによって押さえ部材１４がベース１に取り付けられると、付勢部１５の当接片１７は送りねじ１０の先端部１１ａと当接する。当接片１７は、送りねじ１０の突起部１１によってスラスト方向、即ち、送りねじ１０の軸方向に押圧されるので、当接片１７は突起１９と当接する。このとき、当接片１７は階段状に形成されている突起１９の上側部１９ａ、下側部１９ｂによって、図４に示すように、送りねじ１０との当接面が図４中の斜め上方を向く。その結果、送りねじ１０には力Ｆ１が印加される。
【００３４】
送りねじ１０に印加される力Ｆ１は、図４に示すように、送りねじの軸方向の分力Ｆｘとこの分力Ｆｘに直交する方向、即ち、送りねじ１０の軸方向に直交する方向の分力Ｆｙとの各成分に分けられる。送りねじ１０には図４及び図５中の矢印Ａで示す方向に移動しようとする力が働くため、送りねじ１０は軸受部４の内面に当接する状態となる。
【００３５】
送りねじ１０は、軸受部４の内面と当接した状態で送りモータ８の回転力によって回転される。その際、図４及び図５中の矢印Ａ、Ｂで示す方向のガタツキが防止され、送りねじ１０の軸方向のガタツキも上述した分力Ｆｘによって当接片１７が送りねじ１０を軸方向に押圧するために防止される。
【００３６】
尚、当接片１７と送りねじ１０の先端部１１ａとが当接することによって生じる力Ｆ１は、当接片１７と先端部１１ａとが当接した状態で、且つ、図４に示すように、送りねじ１０が軸受部４と当接した状態で送りねじ１０が回転駆動されるため、当接片１７と先端部１１ａとが当接すること、送りねじ１０と軸受部４とが当接することによって生じる損失ができるだけ小さくなるように、且つ、送りねじ１０にガタツキを生じない程度に設定されている。換言すると、弾性変位部１６による付勢力は、当接片１７と先端部１１ａとの当接、送りねじ１０と軸受部４との当接によって生じる損失ができるだけ小さくなるように、且つ、送りねじ１０にガタツキを生じない程度に設定されている。
【００３７】
加えて、図５に示すように、軸受部４は、上述したように上側部分が曲面部４ａとしてほぼＵ字状に形成されているので、送りねじ１０の先端部１１ａと当接片１７とが当接した状態で送りねじ１０に働く力Ｆ１の分力Ｆｙによって送りねじ１０のねじ部１３は軸受部４の曲面部４ａの頂点となる位置と当接する。この状態で、送りモータ８からの回転力によって送りねじ１０が回転されると図５中の矢印Ａ、Ｂで示す方向のガタツキを防止することができるのみならず、図５中の矢印Ｄで示す方向のガタツキも抑制することができる。
【００３８】
次に、本発明の第２の実施の形態に係る光学ピックアップの送り機構について、図６を用いて説明する。この第２の実施の形態は、送りねじの付勢部による付勢方向が上述した第１の実施の形態と異なるのみで、他の構成は上述した第１の実施の形態と同様に構成されているのでここでの詳細な説明は省略する。
【００３９】
上述した第１の実施の形態では、図４に示した送りねじ１０の軸方向とこの軸方向と直交する方向の２方向に付勢部１５によって付勢するように構成されていたが、第２の実施の形態では、送りねじ１０の軸方向とこの軸方向に直交する２方向の計３方向に付勢部３０によって付勢するものである。
【００４０】
図６に示すように、付勢部３０を三次元的に傾斜させて、ｘ軸方向、ｙ軸方向及びｚ軸方向に各々分力を発生させる。換言すると、送りねじ１０の軸方向となるｚ軸方向と、軸方向と直交する第１の方向、例えば、ｘ軸方向と、軸方向と直交し、且つ、第１の方向に直交する第２の方向、例えば、ｙ軸方向との各方向の分力を合成した付勢力を付勢部３０によって印加する。そのために、付勢部３０をｘ軸に対して角度αだけ傾斜させるとともに、ｙ軸に対して角度βだけ傾斜させる。
【００４１】
例えば、上述した第１の実施の形態と同様に押さえ部材１４が係合片１４ｂの係合爪１４ｄをベースの係合孔に係合させ、ねじ挿通孔１４ｃを介してねじを押さえ部材１４に挿通し、ベース１にねじ止めすることによって押さえ部材１４がベース１に取り付けられると、付勢部３０は送りねじ１０の先端１１ａと当接する。このとき、送りねじ１０には図６に示す力Ｇが印加される。
【００４２】
送りねじ１０に印加される力Ｇは、図６に示すように、送りねじの軸方向の分力Ｇｚと、この分力Ｇｚと直交する方向、即ち、送りねじ１０の軸方向と直交する第１の方向の分力Ｇｘと、送りねじ１０の軸方向に直交し、且つ、第１の方向に直交する第２の方向の分力Ｇｙとの各成分に分けられる。その結果、送りねじ１０は、軸方向の分力Ｇｚによって軸方向のガタツキが防止されるとともに、軸方向と直交する第１の方向、例えば、図４中の矢印Ａ、Ｂで示す方向のガタツキが防止され、さらに軸方向と直交し、且つ、第１の方向と直交する第２の方向、例えば、図５中の矢印Ｄで示す方向のガタツキも防止することができる。第２の実施の形態の場合、付勢部３０の傾斜角度を変更することによって防止若しくは抑制したいガタツキの方向の分力を大きく発生させてガタツキを防止することができる。
【００４３】
以上のように、本発明に係る各実施の形態では、光学ピックアップを光ディスク２５の径方向に送る送りねじのガタツキを防止することができるので、光学ピックアップの送り動作の際に生じる振動を抑制し、安定した読取動作を実現することができる。
【００４４】
本発明は上述した実施の形態に限らず、本発明の趣旨を大きく逸脱しない範囲で種々の変更が可能であることは勿論のことである。例えば、上述した第１の実施の形態では軸受部４は上面部が曲面部４ａとなるほぼＵ字状に形成されていたが、図７に示すように、上面部が平面部となる形状に形成しても良い。この場合には、上述した第１の実施の形態と同様に当接片１７と先端部１１ａとが当接した状態で送りねじ１０に加わる力Ｆ１の一方の分力Ｆｙによって送りねじ１０は図７中の矢印Ａ方向に付勢されるため、図７中の矢印Ａ、Ｂで示す方向のガタツキを同様に防止することができる。図７中の矢印Ａ、Ｂで示す方向と直交する方向のガタツキは送りねじ１０と軸受部４の内面とのクリアランスを調整することによって抑制することができる。
【００４５】
上述した各実施の形態では、ヘッド送り機構として記録媒体として光ディスクを用いる光ディスク再生装置に用いられる光学ピックアップの送り機構を例に挙げて説明したが、これに限らず光ディスクの記録装置または光ディスクの記録再生装置の光学ピックアップの送り機構や磁気ディスクの記録又は再生装置、或はこれらの記録再生の双方を行うことのできる記録再生装置の磁気ヘッド送り機構にも適用することができる。
【００４６】
【発明の効果】
以上に記載したところから明らかなように、本発明ヘッド送り機構は、ヘッド機構と、先端部が半球状に形成され、ヘッド機構と係合し回転することによってヘッド機構を送る送りねじと、送りねじを回転させる回転駆動機構と、回転駆動機構が配置されると共に少なくとも一方がスラスト軸受として形成され送りねじを支持する一対の軸受部を有するベースと、ベースに設けられると共に、送りねじの先端部と当接し送りねじをスラスト方向とスラスト方向に直交する方向とに付勢する弾性部材とを備え、弾性部材は、基端部と当接部とが屈曲した弾性変位部によってほぼＵ字状となるように形成され、基端部には、弾性部材の内方に向かって突出し、当接部が送りねじの先端部と当接した際に当接部と当接して当接部の送りねじの軸方向の移動量を規制する突起が形成され、突起は、弾性部材の内方に向かって突出すると共に、上側部と該上側部より突出量の大きい下側部とを有する階段状に形成され、弾性部材の当接部が送りねじの先端部によってスラスト方向に押圧されたとき、階段状に形成された突起によって、当接部の送りねじとの当接面が斜め方向を向くようにしたことを特徴とする。
【００４７】
従って、本発明にあっては、送りねじの先端部と当接し送りねじをスラスト方向とスラスト方向に直交する方向とに付勢する弾性部材を備えたので、簡単な構成によりヘッドの送り動作の際の振動を抑制することができる。また、送りねじの先端部が半球状に形成されていて、当接片は送りねじの先端部とほぼ点接触する状態になるので、当接片と先端部とが当接した状態で送りねじが回転されることによって生じる摩擦も小さくすることができる。このようにして、送りねじや軸受の部品寸法を変更しなくても、軸受内での送りねじのがたつきが防止される。
そして、さらに、弾性部材の当接部が送りねじの先端部によってスラスト方向に押圧されたとき、階段状に形成された突起によって、当接部の送りねじとの当接面が斜め方向を向くようにしたので、送りねじは弾性部材によって２方向に付勢され、２方向のがたつきを抑制することができる。
【００５０】
また、本発明光学ピックアップの送り機構にあっては、光学ピックアップが設けられたピックアップベースと、ピックアップベースをガイドするガイド機構と、先端部が半球状に形成され、ピックアップベースと係合し回転することによってピックアップベースをガイド機構に沿って送る送りねじと、送りねじを回転させる回転駆動機構と、回転駆動機構が配置されると共に少なくとも一方がスラスト軸受として形成され送りねじを支持する一対の軸受部を有するベースと、ベースに設けられると共に、送りねじの先端部と当接し送りねじをスラスト方向とスラスト方向に直交する方向とに付勢する弾性部材とを備え、弾性部材は、基端部と当接部とが屈曲した弾性変位部によってほぼＵ字状となるように形成され、基端部には、弾性部材の内方に向かって突出し、当接部が送りねじの先端部と当接した際に当接部と当接して当接部の送りねじの軸方向の移動量を規制する突起が形成され、突起は、弾性部材の内方に向かって突出すると共に、上側部と該上側部より突出量の大きい下側部とを有する階段状に形成され、弾性部材の当接部が送りねじの先端部によってスラスト方向に押圧されたとき、階段状に形成された突起によって、当接部の送りねじとの当接面が斜め方向を向くようにしたことを特徴とする。
【００５１】
従って、本発明にあっては、送りねじの先端部と当接し送りねじをスラスト方向とスラスト方向に直交する方向とに付勢する弾性部材を備えたので、簡単な構成によりヘッドの送り動作の際の振動を抑制することができる。また、送りねじの先端部が半球状に形成されていて、当接片は送りねじの先端部とほぼ点接触する状態になるので、当接片と先端部とが当接した状態で送りねじが回転されることによって生じる摩擦も小さくすることができる。このようにして、送りねじや軸受の部品寸法を変更しなくても、軸受内での送りねじのがたつきが防止される。
そして、さらに、弾性部材の当接部が送りねじの先端部によってスラスト方向に押圧されたとき、階段状に形成された突起によって、当接部の送りねじとの当接面が斜め方向を向くようにしたので、送りねじは弾性部材によって２方向に付勢され、２方向のがたつきを抑制することができる。
【００６１】
尚、上記した各実施の形態に示した各部の形状及び構造は、何れも本発明を実施するに際しての具体化のほんの一例を示したものにすぎず、これらによって本発明の技術的範囲が限定的に解釈されるものであってはならないものである。
【図面の簡単な説明】
【図１】本発明の第１の実施の形態に係る光学ピックアップの送り機構の構成を示す平面図である。
【図２】第１の実施の形態に係る光学ピックアップの要部を示す拡大背面図である。
【図３】第１の実施の形態に係る光学ピックアップに用いられる押さえ部材の拡大斜視図である。
【図４】送りねじが軸受部の内面に押し付けられた状態を示す拡大断面図である。
【図５】図４のＶ−Ｖ線に沿う断面図である。
【図６】本発明の第２の実施の形態に係る光学ピックアップの送り機構の要部を示す斜視図である。
【図７】軸受部の変形例を示す拡大断面図である。
【図８】従来の送り機構の一例を示す拡大断面図である。
【符号の説明】
１…ベース、４…軸受部、５…軸受部、８…送りモータ（回転駆動機構）、８ａ…駆動ギヤ（回転駆動機構）、９…中間ギヤ（回転駆動機構）、１０…送りねじ、１１ａ…先端部、１５…付勢部（弾性部材）、１６…基端部、１７…当接片（当接部）、１８…弾性変位部、１９…突起、１９ａ…上側部、１９ｂ…下側部、２０…光学ピックアップ、２０ａ…送りベース（ピックアップベース）、３０…付勢部（弾性部材） [0001]
BACKGROUND OF THE INVENTION
The present invention relates to a head feeding mechanism and an optical pickup feeding mechanism. In particular, the present invention relates to a head feed mechanism using a feed screw and a feed mechanism of an optical pickup.
[0002]
[Prior art]
Disc-shaped recording medium, for example, recording information signals on an optical disc or reading information signals from an optical disc, or using a feed screw for the feeding mechanism of an optical pickup that is a head for both recording and reading There is. An example of such a feed mechanism is shown in FIG.
[0003]
The feed screw a is formed by integrally forming a screw shaft portion b and a gear portion c and a receiving portion d which are continuous to one end of the screw shaft portion b, and can be freely rotated by two bearings separated in the axial direction. It is supported.
[0004]
In the feed screw a, the end portion of the screw shaft portion b on the side where the gear portion c and the receiving portion d are not formed is supported by a thrust bearing (not shown), and the end portion on the opposite side of the screw shaft portion b is supported by the bearing e. ing. The gear part c is connected to the motor via an intermediate gear (not shown), and the receiving part b is elastically contacted with the elastic body f, whereby the feed screw a is pressed in the axial direction by the force F2 shown in FIG. It is energized.
[0005]
One end of the bearing e is opened to attach the feed screw a, and a pressing member g is attached to the opening surface side to prevent the feed screw a from falling off the bearing e.
[0006]
In the feed screw a, the screw shaft portion b is screwed with a feed nut portion provided on the base body of the optical pickup (not shown), and the optical pickup is moved in the radial direction of the optical disc as the feed screw a is rotated by the rotation of the motor. It has become so.
[0007]
[Problems to be solved by the invention]
Incidentally, in the feed mechanism shown in FIG. 8, gaps Δx1 and Δx2 necessary for operation are provided between the feed screw a and the bearing e.
[0008]
The gaps Δx1 and Δx2 cause the feed screw a to rattle in the direction C shown in FIG. 8 when the feed screw a rotates, and vibration is generated due to the collision between the feed screw a and the bearing e. If the generation of such vibration is transmitted to the optical pickup, it may hinder reading of the signal recorded on the optical disk by the optical pickup, and there is a possibility that sound jump due to track jump may occur when the vibration is large.
[0009]
In order to eliminate the above-described problems, it may be possible to determine the dimensions of the feed screw a and the bearing e so that the gaps Δx1 and Δx2 are minimized. There arises a new problem that the rotational loss (load) of the feed screw a and the bearing e increases.
[0010]
In particular, as described above, when the bearing e and the pressing member g provided on the opening surface side thereof are formed as separate members, it is extremely difficult to minimize Δx1 and Δx2 due to the occurrence of dimensional tolerances between them. It is.
[0011]
Therefore, the head feeding mechanism and the optical pickup feeding mechanism of the present invention overcome the above-mentioned problems and prevent the feed screw from rattling in the bearing without changing the dimensions of the feed screw or the bearing. It is an object to reduce the transmitted vibration.
[0012]
[Means for Solving the Problems]
  In order to solve the above-described problems, the head feed mechanism of the present invention includes a head mechanism, a feed screw that feeds the head mechanism by engaging and rotating with the head mechanism, and a feed screw. A rotation drive mechanism for rotation, a base having a rotation drive mechanism and at least one of which is formed as a thrust bearing and having a pair of bearing portions for supporting the feed screw; An elastic member that urges the contact feed screw in a thrust direction and a direction orthogonal to the thrust direction, and the elastic member is substantially U-shaped by an elastic displacement portion in which a base end portion and a contact portion are bent. The base end portion protrudes inward of the elastic member, and when the contact portion comes into contact with the distal end portion of the feed screw, the contact portion comes into contact with the shaft of the feed screw of the contact portion. The amount of movement in the direction A protrusion is formed, and the protrusion protrudes inward of the elastic member and is formed in a stepped shape having an upper portion and a lower portion having a larger protruding amount than the upper portion. When the portion is pressed in the thrust direction by the tip of the feed screw, the contact surface of the contact portion with the feed screw is directed obliquely by a step formed in a step shape.
[0013]
  Further, in order to solve the above-described problems, the optical pickup feeding mechanism of the present invention has a pickup base provided with an optical pickup, a guide mechanism for guiding the pickup base, and a tip portion formed in a hemispherical shape. A feed screw that feeds the pickup base along the guide mechanism by engaging and rotating, a rotation drive mechanism that rotates the feed screw, and a rotation drive mechanism, and at least one of which is formed as a thrust bearing, An elastic member provided with a base having a pair of bearing portions to be supported, and an elastic member that is provided on the base and urges the feed screw in a thrust direction and a direction orthogonal to the thrust direction by contacting the tip of the feed screw Is formed so as to be substantially U-shaped by the elastic displacement portion where the base end portion and the contact portion are bent, The end protrudes inward of the elastic member, and when the abutting portion comes into contact with the leading end of the feed screw, the abutting portion comes into contact with the abutting portion, and the amount of movement of the abutting portion in the axial direction of the feed screw is reduced. A restricting protrusion is formed, and the protrusion protrudes inward of the elastic member, and is formed in a stepped shape having an upper portion and a lower portion having a larger protruding amount than the upper portion, and is in contact with the elastic member. When the portion is pressed in the thrust direction by the tip of the feed screw, the contact surface of the contact portion with the feed screw is directed obliquely by a step formed in a step shape.
[0014]
  Therefore, in the present invention,Since the elastic member that abuts the tip of the feed screw and urges the feed screw in the thrust direction and the direction orthogonal to the thrust direction is provided, vibration during the head feed operation can be suppressed with a simple configuration. . In addition, since the tip of the feed screw is formed in a hemispherical shape, the contact piece is in a point contact state with the tip of the feed screw, so that the feed screw is in contact with the contact piece and the tip. Friction caused by rotating the can be reduced. In this way, without changing the lead screw or bearing part dimensions,Shaking of the feed screw in the bearing is prevented.
[0015]
DETAILED DESCRIPTION OF THE INVENTION
The head feed mechanism according to the present invention will be described below with reference to the drawings. In each of the embodiments of the present invention described below, a feeding mechanism for an optical pickup used in an optical disc reproducing apparatus that uses a read-only optical disc (hereinafter simply referred to as “optical disc”) such as a so-called compact disc as a recording medium. An example will be described.
[0016]
As shown in FIG. 1, the feeding mechanism of the optical pickup according to the first embodiment has a base 1 made of synthetic resin. The base 1 is formed with an opening 2 and an attachment opening 3. The opening 2 is formed in a rectangular shape along the radial direction of the optical disk 25, and an optical pickup described later moves in the opening 2 in the radial direction of the optical disk 25. The attachment opening 3 is formed in a substantially circular shape, and a spindle motor (not shown) is attached thereto.
[0017]
A disc table 24 on which the optical disc 25 is placed is attached to the tip end side of the rotating shaft of the spindle motor attached to the attachment opening 3. For example, the optical disk 25 placed on the disk table 24 is rotationally driven at a constant linear velocity. The opening 2 is formed in a size sufficient to scan at least the entire signal recording area of the optical disc 25 by an optical pickup described later.
[0018]
The optical pickup 20 includes an objective lens 21, an actuator (not shown) for driving the objective lens 21 in a focusing direction and a tracking direction, a semiconductor laser (not shown) as a light source, a photodetector (not shown), an optical system and an actuator (not shown), and a semiconductor laser. And a feed base 20a on which a photodetector and an optical system are provided.
[0019]
The objective lens 21 is arranged on the feed base 20a so as to draw a movement locus that coincides with a straight line passing through the diameter of the optical disc 25 when the optical pickup 20 is fed in the radial direction of the optical disc 25 by a feed mechanism described later. Yes. The feed base 20a is provided with a nut portion 22 that engages with a feed screw that will be described later and an engagement claw 23 that engages with a guide portion that will be described later. The engaging claw 23 is disposed between a pair of projecting pieces 20b and 20b each formed with an insertion hole through which a feed screw to be described later is inserted.
[0020]
The base 1 is provided with a pair of bearing portions 4 and 5 on one side with an optical pickup 20 disposed in the opening 2 interposed therebetween, and a guide portion 6 is provided on the other side.
[0021]
As shown in FIG. 5, one of the pair of bearings 4 and 5 has a cross-section opened toward the back side of the paper surface seen in FIG. 1, for example, and the upper half is a curved surface portion 4 a. It is formed so as to be substantially U-shaped. The other bearing portion 5 is formed as a thrust bearing portion that opens toward the inside of the opening 2. The engaging claw 23 of the feed base 20a is engaged with the guide portion 6.
[0022]
As shown in FIGS. 1 and 2, a mounting portion 7 formed so as to protrude from the base 1 has a feed motor 8, a drive gear 8 a that constitutes a feed mechanism as a rotation drive mechanism of a feed screw, and an intermediate gear. 9 is arranged. The feed motor 8 is disposed on the mounting portion 7 so that the rotation shaft is substantially parallel to a feed screw described later. A drive gear 8 a is attached to the rotation shaft of the feed motor 8, and the drive gear 8 a meshes with the intermediate gear 9. The intermediate gear 9 is attached to the attachment portion 7 so that the rotation shaft of the intermediate gear 9 is rotatable.
[0023]
As shown in FIG. 1, the base 1 is provided with a plurality of protruding pieces 1 a and 1 b that protrude outward from the base 1. These protruding pieces 1a and 1b are respectively attached to a chassis of a reproducing apparatus (not shown) via a damper as necessary. Although only two protruding pieces are shown in FIG. 1 for the sake of the drawing, actually three protruding pieces are formed on the base 1.
[0024]
As shown in FIG. 1, the feed screw 10 has a screw portion 13 formed almost entirely, and a gear portion 12 and a projection portion 11 are provided on one end side. The screw part 13 and the protrusion part 11 are integrally formed, and are formed by fitting the gear 12 into the feed screw 10 later. As shown in FIGS. 1 and 2, the protruding portion 11 protrudes from the screw portion 12 of the feed screw 10 and is formed so that the tip end portion 11 a is hemispherical. The tip 11a of the projection 11 abuts on an urging portion described later.
[0025]
The feed screw 10 is on the side opposite to the side where the guide portion 6 of the base 1 is provided with the optical pickup 20 in between, and one end is pivotally supported by the bearing portion 4 so as to extend across the opening 2. The end is pivotally supported by a bearing portion 5 as a thrust bearing portion. The feed screw 10 is inserted through the insertion holes of the pair of protruding pieces 20b and 20b of the feed base 20a, and the screw portion 13 and the nut portion 22 of the feed base 20a are engaged with each other.
[0026]
The gear portion 12 of the feed screw 10 is meshed with the intermediate gear 9 described above. As a result, the rotational force of the feed motor 8 is transmitted to the feed screw 10 via the drive gear 8a and the intermediate gear 9, and the feed screw 10 is rotated. Since the feed screw 10 and the nut portion 22 of the optical pickup 20 are engaged with each other, the optical pickup 20 is moved along the guide portion 6 in the radial direction of the optical disc 25 by rotating the feed screw 10. As a result, the optical beam irradiated onto the optical disc 25 from the objective lens 21 scans the optical disc 25 and data recorded on the optical disc 25 is read out.
[0027]
As shown in FIGS. 1 and 2, a pressing member 14 is attached to the base 1 so as to cover one surface side of the feed motor 8, the drive gear 8 a, and the intermediate gear 9 that rotationally drives the feed screw 10. As shown in FIG. 3, the pressing member 14 has an engaging piece 14 b and a screw inserted into a plate-like portion 14 a formed to have a size sufficient to cover one side of the feed motor 8, the drive gear 8 a, and the intermediate gear 9. The hole 14c and the urging portion 15 are integrally formed using a synthetic resin material.
[0028]
The engaging piece 14b is formed so as to protrude from the plate-like portion 14a, and an engaging claw 14d that engages with an engaging hole (not shown) formed in the base 1 is formed at the tip portion. A screw is inserted into the screw insertion hole 14c in a state where the engagement claw 14d is engaged with the engagement hole of the base 1, and the pressing member 14 is engaged with the screw mounting hole (not shown) of the base 1 so that the holding member 14 is 1 is attached so as to cover one surface side of the feed motor 8, the drive gear 8a, and the intermediate gear 9.
[0029]
As shown in FIGS. 1 and 2, the urging portion 15 formed on the pressing member 14 comes into contact with the distal end portion 11 a of the protruding portion 11 of the feed screw 10 in a state where the pressing member 14 is attached to the base 1.
[0030]
  The biasing portion 15 has a base end portion 16 and a contact portion.(Contact piece)17 is formed to be substantially U-shaped by an elastic displacement portion 18 bent. The base end portion 16 is formed with a protrusion 19 that protrudes inward of the biasing portion 15. The protrusion 19 abuts against the abutting piece 17 when the abutting portion 17 abuts on the tip end portion 11 a of the projecting portion 11 of the feed screw 10, thereby restricting the amount of movement of the abutting piece 17 in the axial direction of the feed screw 10. In addition, as shown in FIG. 4, an urging force is applied to the feed screw 10.
[0031]
As shown in FIGS. 3 and 4, the protrusion 19 is formed in a stepped shape that protrudes inward of the urging portion 15, and includes an upper portion 19 a and a lower portion 19 b having a larger protruding amount than the upper portion 19 a. Have Since the tip end portion 11a of the feed screw 10 is formed in a hemispherical shape as described above, the contact piece 17 is in a point contact state with the tip end portion 11a of the feed screw 10; The loss caused by the rotation of the feed screw 10 in a state in which it is in contact with 11a can be minimized.
[0032]
The urging force applied to the feed screw 10 when the pressing member 14 is attached to the base 1 and abuts against the tip end portion 11a of the projection 11 of the feed screw 10 will be described with reference to FIG.
[0033]
As described above, the pressing member 14 engages the engaging claw 14d of the engaging piece 14b with the engaging hole of the base, the screw is inserted into the pressing member 14 through the screw insertion hole 14c, and the base 1 is screwed. Thus, when the pressing member 14 is attached to the base 1, the abutting piece 17 of the urging portion 15 comes into contact with the distal end portion 11 a of the feed screw 10. Since the contact piece 17 is pressed in the thrust direction, that is, the axial direction of the feed screw 10 by the protrusion 11 of the feed screw 10, the contact piece 17 contacts the protrusion 19. At this time, as shown in FIG. 4, the contact piece 17 has an upper surface 19a and a lower side 19b of the protrusion 19 formed in a step shape so that the contact surface with the feed screw 10 is obliquely upward in FIG. Facing. As a result, a force F1 is applied to the feed screw 10.
[0034]
As shown in FIG. 4, the force F1 applied to the feed screw 10 is a component force Fx in the axial direction of the feed screw and a direction perpendicular to the component force Fx, that is, a direction perpendicular to the axial direction of the feed screw 10. It is divided into each component with the component force Fy. Since the force to move in the direction indicated by the arrow A in FIGS. 4 and 5 acts on the feed screw 10, the feed screw 10 comes into contact with the inner surface of the bearing portion 4.
[0035]
The feed screw 10 is rotated by the rotational force of the feed motor 8 while in contact with the inner surface of the bearing portion 4. At this time, rattling in the directions indicated by arrows A and B in FIGS. 4 and 5 is prevented, and the shakiness in the axial direction of the feed screw 10 is also caused by the contact piece 17 to move the feed screw 10 in the axial direction by the above-described component force Fx. Prevented to press.
[0036]
Note that the force F1 generated by the contact between the contact piece 17 and the distal end portion 11a of the feed screw 10 is in a state where the contact piece 17 and the distal end portion 11a are in contact with each other, as shown in FIG. Since the feed screw 10 is rotationally driven in a state where the feed screw 10 is in contact with the bearing portion 4, the contact piece 17 and the tip end portion 11 a come into contact with each other, and the feed screw 10 and the bearing portion 4 come into contact with each other. It is set so that the generated loss is as small as possible and the feed screw 10 is not rattled. In other words, the urging force by the elastic displacement portion 16 is such that the loss caused by the contact between the contact piece 17 and the tip portion 11a and the contact between the feed screw 10 and the bearing portion 4 is as small as possible, and the feed screw. 10 is set to such an extent that no rattling occurs.
[0037]
In addition, as shown in FIG. 5, the bearing portion 4 is formed in a substantially U shape as the curved portion 4 a as described above, so that the tip end portion 11 a of the feed screw 10 and the contact piece 17 are formed. The threaded portion 13 of the feed screw 10 comes into contact with the position that is the apex of the curved surface portion 4a of the bearing portion 4 by the component force Fy of the force F1 acting on the feed screw 10 in the state where the In this state, when the feed screw 10 is rotated by the rotational force from the feed motor 8, not only can the play in the directions indicated by the arrows A and B in FIG. 5 be prevented, but also the arrow D in FIG. The backlash of the direction shown can also be suppressed.
[0038]
Next, an optical pickup feeding mechanism according to a second embodiment of the present invention will be described with reference to FIG. This second embodiment is different from the first embodiment described above only in the biasing direction by the biasing portion of the feed screw, and the other configuration is the same as that of the first embodiment described above. Therefore, detailed description here is omitted.
[0039]
In the first embodiment described above, the biasing portion 15 urges the feed screw 10 in the axial direction and the direction orthogonal to the axial direction shown in FIG. In the second embodiment, the urging unit 30 urges the feed screw 10 in a total of three directions, ie, the axial direction of the feed screw 10 and two directions orthogonal to the axial direction.
[0040]
As shown in FIG. 6, the urging portion 30 is tilted three-dimensionally to generate component forces in the x-axis direction, the y-axis direction, and the z-axis direction, respectively. In other words, the z-axis direction that is the axial direction of the feed screw 10 and a first direction that is orthogonal to the axial direction, for example, the x-axis direction, and the second direction that is orthogonal to the axial direction and orthogonal to the first direction. The urging unit 30 applies an urging force obtained by synthesizing the component forces in the respective directions, for example, the y-axis direction. For this purpose, the urging portion 30 is inclined by an angle α with respect to the x axis and is inclined by an angle β with respect to the y axis.
[0041]
For example, as in the first embodiment described above, the pressing member 14 engages the engaging claw 14d of the engaging piece 14b with the engaging hole of the base, and the screw is attached to the pressing member 14 via the screw insertion hole 14c. When the pressing member 14 is attached to the base 1 by being inserted and screwed to the base 1, the urging portion 30 contacts the tip 11 a of the feed screw 10. At this time, the force G shown in FIG.
[0042]
As shown in FIG. 6, the force G applied to the feed screw 10 includes a component force Gz in the axial direction of the feed screw and a direction perpendicular to the component force Gz, that is, a direction perpendicular to the axial direction of the feed screw 10. It is divided into components of a component force Gx in one direction and a component force Gy in a second direction orthogonal to the axial direction of the feed screw 10 and orthogonal to the first direction. As a result, the feed screw 10 is prevented from rattling in the axial direction by the axial component force Gz, and is also playable in a first direction orthogonal to the axial direction, for example, in the direction indicated by arrows A and B in FIG. Further, rattling in a second direction perpendicular to the axial direction and perpendicular to the first direction, for example, the direction indicated by the arrow D in FIG. 5 can be prevented. In the case of the second embodiment, by changing the inclination angle of the urging portion 30, a large component force in the direction of backlash to be prevented or suppressed can be generated to prevent backlash.
[0043]
As described above, in each embodiment according to the present invention, it is possible to prevent rattling of the feed screw that feeds the optical pickup in the radial direction of the optical disc 25, so that vibration that occurs during the feeding operation of the optical pickup is suppressed. A stable reading operation can be realized.
[0044]
It goes without saying that the present invention is not limited to the above-described embodiment, and various modifications can be made without departing from the spirit of the present invention. For example, in the first embodiment described above, the bearing portion 4 is formed in a substantially U shape with the upper surface portion being the curved surface portion 4a. However, as shown in FIG. It may be formed. In this case, as in the first embodiment described above, the feed screw 10 is shown in the figure by one component force Fy of the force F1 applied to the feed screw 10 in a state where the contact piece 17 and the tip portion 11a are in contact. 7 is urged in the direction of arrow A in FIG. 7, rattling in the directions indicated by arrows A and B in FIG. 7 can be similarly prevented. The backlash in the direction orthogonal to the directions indicated by arrows A and B in FIG. 7 can be suppressed by adjusting the clearance between the feed screw 10 and the inner surface of the bearing portion 4.
[0045]
In each of the above-described embodiments, the optical pickup feeding mechanism used in the optical disk reproducing apparatus using an optical disk as a recording medium as the head feeding mechanism has been described as an example. However, the present invention is not limited to this, and the optical disk recording apparatus or the optical disk recording is not limited thereto. The present invention can also be applied to a feeding mechanism of an optical pickup of a reproducing apparatus, a recording / reproducing apparatus of a magnetic disk, or a magnetic head feeding mechanism of a recording / reproducing apparatus capable of performing both recording and reproducing.
[0046]
【The invention's effect】
  As is apparent from the above description, the head feed mechanism of the present invention includes a head mechanism, a feed screw that feeds the head mechanism by rotating in engagement with the head mechanism, the tip portion being hemispherical, A rotation drive mechanism for rotating the screw, a base having the rotation drive mechanism and at least one of which is formed as a thrust bearing and having a pair of bearing portions for supporting the feed screw; and a tip of the feed screw provided on the base And an elastic member that urges the feed screw in a thrust direction and a direction orthogonal to the thrust direction, and the elastic member is substantially U-shaped by an elastic displacement portion in which a base end portion and a contact portion are bent. The base end portion protrudes inward of the elastic member, and when the abutting portion comes into contact with the distal end portion of the feed screw, the abutting portion comes into contact with the advancing screw. Axial direction of A protrusion that restricts the amount of movement is formed, the protrusion protrudes inward of the elastic member, and is formed in a staircase shape having an upper portion and a lower portion having a larger protrusion amount than the upper portion. When the abutting portion of the abutting portion is pressed in the thrust direction by the tip end portion of the feed screw, the abutment surface of the abutting portion with the feed screw is directed obliquely by a step formed in a step shape. And
[0047]
  Accordingly, in the present invention, since the elastic member that abuts the leading end portion of the feed screw and urges the feed screw in the thrust direction and the direction orthogonal to the thrust direction is provided, the head feed operation can be performed with a simple configuration. Vibration at the time can be suppressed. In addition, since the tip of the feed screw is formed in a hemispherical shape, the contact piece is in a point contact state with the tip of the feed screw, so that the feed screw is in contact with the contact piece and the tip. Friction caused by rotating the can be reduced. In this way, rattling of the feed screw within the bearing is prevented without changing the dimensions of the feed screw or the parts of the bearing.
  Further, when the contact portion of the elastic member is pressed in the thrust direction by the tip portion of the feed screw, the contact surface of the contact portion with the feed screw is directed obliquely by the step formed in a step shape. Since it did in this way, a feed screw is urged | biased by two directions with an elastic member, and it can suppress the shakiness of two directions.
[0050]
  In the feeding mechanism of the optical pickup of the present invention, the pickup base provided with the optical pickup, the guide mechanism for guiding the pickup base, and the tip end portion are formed in a hemispherical shape, and engage with the pickup base to rotate. Accordingly, a feed screw that feeds the pickup base along the guide mechanism, a rotation drive mechanism that rotates the feed screw, and a pair of bearing portions that are disposed as a thrust bearing and that support the feed screw are disposed. And a base provided on the base, and an elastic member that abuts the leading end portion of the feed screw and biases the feed screw in the thrust direction and a direction orthogonal to the thrust direction. The abutting portion is formed to be substantially U-shaped by the bent elastic displacement portion, and the base end portion is formed of the elastic member. A protrusion that restricts the amount of movement of the feed screw in the axial direction by contacting the contact portion when the contact portion contacts the tip of the feed screw. And projecting inward of the elastic member, and having an upper portion and a lower portion having a larger protruding amount than the upper portion, the abutting portion of the elastic member being thrust by the tip of the feed screw When pressed in the direction, the contact surface with the feed screw of the contact portion is directed obliquely by a step formed in a step shape.
[0051]
  Accordingly, in the present invention, since the elastic member that abuts the leading end portion of the feed screw and urges the feed screw in the thrust direction and the direction orthogonal to the thrust direction is provided, the head feed operation can be performed with a simple configuration. Vibration at the time can be suppressed. In addition, since the tip of the feed screw is formed in a hemispherical shape, the contact piece is in a point contact state with the tip of the feed screw, so that the feed screw is in contact with the contact piece and the tip. Friction caused by rotating the can be reduced. In this way, rattling of the feed screw within the bearing is prevented without changing the dimensions of the feed screw or the parts of the bearing.
  Further, when the contact portion of the elastic member is pressed in the thrust direction by the tip portion of the feed screw, the contact surface of the contact portion with the feed screw is directed obliquely by the step formed in a step shape. Since it did in this way, a feed screw is urged | biased by two directions with an elastic member, and it can suppress the shakiness of two directions.
[0061]
It should be noted that the shapes and structures of the respective parts shown in the above-described embodiments are merely examples of implementation in carrying out the present invention, and the technical scope of the present invention is limited by these. It should not be interpreted as a matter of course.
[Brief description of the drawings]
FIG. 1 is a plan view showing a configuration of a feeding mechanism of an optical pickup according to a first embodiment of the present invention.
FIG. 2 is an enlarged rear view showing a main part of the optical pickup according to the first embodiment.
FIG. 3 is an enlarged perspective view of a pressing member used in the optical pickup according to the first embodiment.
FIG. 4 is an enlarged cross-sectional view showing a state in which the feed screw is pressed against the inner surface of the bearing portion.
5 is a cross-sectional view taken along line VV in FIG.
FIG. 6 is a perspective view showing a main part of an optical pickup feeding mechanism according to a second embodiment of the present invention.
FIG. 7 is an enlarged cross-sectional view showing a modified example of the bearing portion.
FIG. 8 is an enlarged sectional view showing an example of a conventional feeding mechanism.
[Explanation of symbols]
  DESCRIPTION OF SYMBOLS 1 ... Base, 4 ... Bearing part, 5 ... Bearing part,8 ... Feed motor (rotary drive mechanism), 8a ... drive gear (rotary drive mechanism), 9 ... intermediate gear (rotary drive mechanism),10 ... feed screw,11a ... the tip,15 ... Biasing part(Elastic member), 16 ... proximal end,17 ... contact piece (contact part), 18 ... elastic displacement part,19 ... Projection, 19a ... Upper part, 19b ... Lower part,20 ... Optical pickup, 20a ... Feed base (pickup base), 30 ... Biasing part(Elastic member)

Claims

A head mechanism;
A lead screw that has a hemispherical tip and feeds the head mechanism by engaging and rotating with the head mechanism;
A rotational drive mechanism for rotating the feed screw;
A base having a pair of bearing portions in which the rotational drive mechanism is arranged and at least one of which is formed as a thrust bearing and supports a feed screw;
An elastic member that is provided on the base and abuts against the tip of the feed screw and biases the feed screw in a thrust direction and a direction orthogonal to the thrust direction;
The elastic member is formed to be substantially U-shaped by an elastic displacement portion in which a base end portion and a contact portion are bent,
The base end protrudes inward of the elastic member, and when the abutting portion comes into contact with the distal end portion of the feed screw, the abutting portion comes into contact with the feed of the abutting portion. Protrusions that regulate the amount of axial movement of the screw are formed,
The protrusion protrudes inward of the elastic member and is formed in a stepped shape having an upper part and a lower part having a larger protruding amount than the upper part,
When the contact portion of the elastic member is pressed in the thrust direction by the tip portion of the feed screw, the contact surface of the contact portion with the feed screw faces in an oblique direction by the projection formed in a step shape. A head feed mechanism characterized by that.

A pickup base provided with an optical pickup;
A guide mechanism for guiding the pickup base;
A lead screw whose tip is formed in a hemispherical shape and engages with the pickup base and rotates to feed the pickup base along the guide mechanism;
A rotational drive mechanism for rotating the feed screw;
A base having a pair of bearing portions in which the rotational drive mechanism is arranged and at least one of which is formed as a thrust bearing and supports a feed screw;
An elastic member that is provided on the base and abuts against the tip of the feed screw and biases the feed screw in a thrust direction and a direction orthogonal to the thrust direction;
The elastic member is formed to be substantially U-shaped by an elastic displacement portion in which a base end portion and a contact portion are bent,
The base end protrudes inward of the elastic member, and when the abutting portion comes into contact with the distal end portion of the feed screw, the abutting portion comes into contact with the feed of the abutting portion. Protrusions that regulate the amount of axial movement of the screw are formed,
The protrusion protrudes inward of the elastic member and is formed in a stepped shape having an upper part and a lower part having a larger protruding amount than the upper part,
When the contact portion of the elastic member is pressed in the thrust direction by the tip portion of the feed screw, the contact surface of the contact portion with the feed screw faces in an oblique direction by the projection formed in a step shape. An optical pickup feeding mechanism characterized by the above.