JP2004298498A

JP2004298498A - Position retaining mechanism

Info

Publication number: JP2004298498A
Application number: JP2003097042A
Authority: JP
Inventors: Hirotaka Inaba; 博隆稲葉
Original assignee: Toyota Industries Corp
Current assignee: Toyota Industries Corp
Priority date: 2003-03-31
Filing date: 2003-03-31
Publication date: 2004-10-28
Anticipated expiration: 2023-03-31
Also published as: JP4352742B2

Abstract

<P>PROBLEM TO BE SOLVED: To render a backlash less in a position adjusting direction in a retained position where the position is adjusted. <P>SOLUTION: A pair of engagement grooves 19a and 19b provided on a support part 18 of a stay engage with a pair of nipping parts 22a and 22b of a spring 17 through a pair of opening parts 20a and 20b provided on a holder 16. A pair of the opening parts 20a and 20b are provided on the same position in an axial direction of the holder 16, and the width thereof W in the axial direction is wider by a specified value ΔS than the outer diameters R of the nipping parts 22a and 22b. The engagement grooves 19a and 19b are provided in positions apart from each other by the specified value ΔS in the axial direction. In an engagement state of the nipping parts 22a and 22b with the grooves 19a and 19b, the nipping part 22a abuts on an inner face 23a of an upper side of the opening part 20a and the nipping part 22b abuts on an inner face 23b of a lower side of the opening part 20b. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

【０００１】
【発明の属する技術分野】
本発明は、例えば車両用シートの座部に設けられた荷落ち防止板や、同じく背もたれ部に設けられたヘッドレスト等の高さを調節して所要の位置で保持することができる位置保持機構に関するものである。
【０００２】
【従来の技術】
例えば、車両用シートのヘッドレストは、車両シートの背もたれ部に内蔵された高さ保持機構によってその高さが調節され、所要の高さで保持される。
【０００３】
従来の高さ保持機構には、ヘッドレストに固定されたステーを、シートバックに固定されたガイドパイプに沿って移動させるとともに、ガイドパイプに支持されたスプリングを、ステーの係合溝に係合させることで、ヘッドレストの高さを調節するものがある（例えば、特許文献１，２，３参照。）。
【０００４】
図１２〜図１４に示すように、スプリング５０は、ステー５１の軸線方向における複数箇所に設けられた係合溝５２のいずれかに挟持状態で係合することによって、ホルダ５３に対するステー５１の相対移動を規制し、ヘッドレストを所要の高さで保持する。
【０００５】
【特許文献１】
実開昭５９−１７１５５１号公報（第３図〜第７図）
【特許文献２】
実開昭６２−１８５５５６号公報（第３図、第４図）
【特許文献３】
実開昭６３−５２４５４号公報（第３図、第７図）
【０００６】
【発明が解決しようとする課題】
図１３に示すように、スプリング５０は、ホルダ５３に設けられた開口部５４内に配置されている。図１２に示すように、開口部５４は、ホルダ５３の軸線方向におけるその幅Ｗが、スプリング５０の弾性変形を妨げない範囲で、できるだけスプリング５０の外径Ｒに近い大きさとされている。すなわち、幅Ｗは、スプリング５０が円滑に開閉方向に変位するための必要最小限の隙間Ｔを外径Ｒに加えた大きさとされている。これにより、ホルダ５３、すなわちヘッドレストが上下方向にがたつき難いようになっている。
【０００７】
しかしながら、前記隙間Ｔが存在すれば、その隙間Ｔ分だけステー５１ががたつくのは避けることができない。つまり、図１５（グラフ）に示すように、ヘッドレストが各調節位置に配置された状態において、開口部５４とスプリング５０との間の隙間Ｔ（＝Ｗ−Ｒ）分だけはスプリング５０による保持力がほとんど発生しない範囲ができる。このため、各調節高さにおいてその隙間Ｔ分だけ上下方向のがたつきが避けられなかった。
【０００８】
本発明は、上記課題を解決するためになされたものであって、その目的は、位置調節された保持位置での位置調節方向におけるがたつきをより小さくすることができる位置保持機構を提供することにある。
【０００９】
【課題を解決するための手段】
上記目的を達成するため、請求項１に記載の発明は、棒状の支持部材と、その支持部材の軸線方向に沿って相対移動可能に同支持部材に外嵌された案内部材と、この案内部材に保持されるとともに前記支持部材を弾性的に挟持可能な弾性挟持部材とを備えている。前記支持部材の外周面の所定位置に、前記弾性挟持部材が係合可能な係合凹部が設けられている。前記案内部材には、前記係合凹部に相対可能な開口部が設けられている。前記弾性挟持部材は、前記開口部を通して前記支持部材を挟持するとともに前記係合凹部に係合可能な一対の挟持部を備えている。一対の前記挟持部が前記係合凹部に係合した状態において、両挟持部の一方が前記軸線方向における一方の側で前記開口部の内面に当接し、かつ、両挟持部の他方が同じく他方の側で前記開口部の内面に当接するように前記係合凹部及び開口部が設けられている。
【００１０】
請求項１に記載の発明によれば、係合凹部に弾性挟持部材の一対の挟持部が係合し、支持部材及び案内部材が所定の位置関係に保持されているときには、一対の挟持部の一方が支持部材の軸線方向における一方の側で開口部の内面に当接し、かつ、他方が同じく他方の側で開口部の内面に当接する。従って、所定の位置関係に保持された支持部材と案内部材との間に、軸線方向におけるがたつきが生じにくい。
【００１１】
請求項２に記載の発明は、請求項１に記載の発明において、前記開口部の前記軸線方向における大きさは、前記挟持部が同軸線方向に略直交する方向に変位するためにほぼ必要最小限の大きさである。
【００１２】
請求項２に記載の発明によれば、請求項１に記載の発明の作用に加えて、所定の位置関係に保持されている支持部材及び案内部材の位置関係を調節するときに、一対の挟持部のいずれか一方のみが係合凹部から外れる状態が発生しない。従って、支持部材と案内部材とが、所定の位置関係に保持された状態から円滑に相対移動して位置調節される。
【００１３】
請求項３に記載の発明は、請求項１又は請求項２に記載の発明において、両挟持部の一方が前記軸線方向における一方の側で前記開口部の内面に当接し、かつ、両挟持部の他方が同じく他方の側で前記開口部の内面に当接するように、一対の前記挟持部が係合する前記係合凹部の両部位が断面略Ｖ字状をなし、両部位の中心同士が前記軸線方向に所定距離だけ離れている。
【００１４】
請求項３に記載の発明によれば、請求項１又は請求項２に記載の発明の作用に加えて、一対の挟持部は、断面略Ｖ字状をなし、中心同士が軸線方向に所定距離だけ離れている係合凹部の両部位に対して係合することによって、軸線方向に所定間隔だけ互いに離れた位置に配置される。これにより、両挟持部の一方が、軸線方向の一方の側で開口部の内面に当接し、両挟持部の他方が、同じく他方の側で開口部の内面に当接する。
【００１５】
請求項４に記載の発明は、請求項１又は請求項２に記載の発明において、前記開口部は、両挟持部の一方が前記軸線方向における一方の側で前記開口部の内面に当接し、かつ、両挟持部の他方が同じく他方の側で前記開口部の内面に当接するように、一対の前記挟持部が配置される前記開口部の両部位の前記内面同士が前記軸線方向に所定距離だけ変位して配置されている。かつ、一対の前記挟持部が係合する前記係合凹部の両部位同士が前記軸線方向の同位置にある。
【００１６】
請求項４に記載の発明によれば、請求項１又は請求項２に記載の発明の作用に加えて、一対の挟持部は、軸線方向の同じ位置で係合凹部に係合する。この状態で、両挟持部の一方が、軸線方向の一方の側で開口部の内面に当接し、両挟持部の他方が、同じく他方の側で開口部の内面に当接する。
【００１７】
請求項５に記載の発明は、棒状の支持部材と、その支持部材の軸線方向に沿って相対移動可能に同支持部材に外嵌された案内部材と、この案内部材に保持されるとともに弾性によって前記支持部材をその略径方向に押圧可能な略棒状のスプリングとを備えている。前記支持部材の外周面の所定位置に、前記スプリングの中央部が係合可能な係合凹部が設けられている。前記スプリングは、その両端部が、前記案内部材に設けられた略Ｖ字状の係止凹部の底部に押圧されることで支持されている。
【００１８】
請求項５に記載の発明によれば、略棒状のスプリングの両端部が、略Ｖ字状の案内作用により係合凹部の底部にそれぞれ押しつけられるとともに、その中央部が支持部材の係合凹部に押しつけられる。このため、案内部材と支持部材との間の位置関係が固定され、両者間にがたつきが生じない。
【００１９】
【発明の実施の形態】
（第１実施形態）
以下、本発明を、車両用シートに設けられた荷落ち防止板の位置保持機構に具体化した第１実施形態を図１〜図６に従って説明する。
【００２０】
図２に示すように、車両用シート１０の座部１１の前端には、その座面上に載置された荷Ｌが車両減速時に座面から落ちないようにするための荷落ち防止板（荷落ち防止部材）１２が設けられている。荷落ち防止板１２は、上下方向におけるその高さが、収容位置Ｐ０、第１使用位置Ｐ１及び第２使用位置Ｐ２の３つの所定高さに調節される。収容位置Ｐ０は、図２に実線で示すように、荷落ち防止板１２を使用しない位置である。第１使用位置Ｐ１は、同じく二点鎖線で示すように、荷落ち防止板１２を座面から所定高さだけ高く出した位置であり、第２使用位置Ｐ２は、同じく第１使用位置Ｐ１よりも座面から高く出した位置である。
【００２１】
荷落ち防止板１２の内部には、収容位置Ｐ０、第１使用位置Ｐ１及び第２使用位置Ｐ２に荷落ち防止板１２を保持するための位置保持装置１３が設けられている。位置保持装置１３は、左右一対の位置保持機構１４ａ，１４ｂからなる。位置保持機構１４ａ，１４ｂは、同一の構成である。
【００２２】
図３（ａ），（ｂ）に示すように、位置保持機構１４ａは、座部１１に固定された金属棒よりなるステー１５と、荷落ち防止板１２に固定され、ステー１５に外嵌されてステー１５を挿通する円筒状のホルダ（案内部材）１６と、ホルダ１６に保持されたスプリング（弾性挟持部材）１７とからなる。
【００２３】
ステー１５は、荷落ち防止板１２の内部で上下方向に立ち上がる支持部（支持部材）１８を有し、この支持部１８に荷落ち防止板１２を支持する。支持部１８の外周面１８ａには、その軸線方向における２箇所の所定位置に、各一対の断面Ｖ字状をなす係合溝（係合凹部）１９ａ，１９ｂが設けられている。
【００２４】
スプリング１７は、一対の係合溝１９ａ，１９ｂに対して係合可能である。そして、スプリング１７が一対の係合溝１９ａ，１９ｂに係合しないときには、支持部１８に対してホルダ１６が容易に上下動する。一方、スプリング１７が一対の係合溝１９ａ，１９ｂに係合するときには、支持部１８に対してホルダ１６が所定の位置関係で保持される。
【００２５】
スプリング１７は断面円形の線状ばねからなり、膨らんだ形状の基部２１の両端から伸びる一対の挟持部２２ａ，２２ｂを有している。スプリング１７が両挟持部２２ａ，２２ｂで支持部１８を挟持するときのばね定数は、基部２１が膨らんだ形状をなすことによってその全長を長くできて、小さく設定されている。
【００２６】
図４（ａ），（ｂ）及び図５に示すように、ホルダ１６には、一対の開口部２０ａ，２０ｂが設けられている。スプリング１７は、両挟持部２２ａ，２２ｂにおいて両開口部２０ａ，２０ｂ内に配置されることでホルダ１６に保持されるとともに、一対の係合溝１９ａ，１９ｂに対し同時に係合した状態で支持部１８を挟持する。
【００２７】
図１に示すように、一対の開口部２０ａ，２０ｂは、ホルダ１６の軸線方向における同じ位置に設けられている。開口部２０ａ，２０ｂの同方向における幅Ｗは、挟持部２２ａ，２２ｂの外径Ｒよりも所定値（例えば、０．２ｍｍ）ΔＳだけ大きく設定されている。この所定値ΔＳは、開口部２０ａ，２０ｂに配置された挟持部２２ａ，２２ｂを、ホルダ１６の径方向に円滑に変位させるために必要最小限な隙間の大きさである。一方、一対の係合溝１９ａ，１９ｂのＶ字状の中心は、支持部１８の軸線方向において、この所定値ΔＳだけずれて配置されている。これにより、一対の挟持部２２ａ，２２ｂが一対の係合溝１９ａ，１９ｂに対して共に係合した状態において、挟持部２２ａが開口部２０ａの上側内面２３ａに当接し、挟持部２２ｂが開口部２０ｂの下側内面２３ｂに当接されている。なお、図面においては、理解を容易にするためにΔＳを大きく描いたが、実際にはこのΔＳはごく僅かの寸法である。
【００２８】
次に、以上のように構成された本実施形態の作用について説明する。
荷落ち防止板１２が第１使用位置Ｐ１又は第２使用位置Ｐ２まで引き上げられると、図１に示すように、スプリング１７の弾性によって両挟持部２２ａ，２２ｂが一対の係合溝１９ａ，１９ｂに共に係合する。このため、荷落ち防止板１２が第１使用位置Ｐ１又は第２使用位置Ｐ２に保持される。
【００２９】
この状態では、図１から明らかなように、係合溝１９ａ，１９ｂ間の所定値ΔＳ分の位置ずれに基づいて、スプリング１７の両挟持部２２ａ，２２ｂがそれぞれホルダ１６の開口部２０ａ又は２０ｂの内面２３ａ，２３ｂに当接する。従って、スプリング１７とホルダ１６との間のがたつきがなくなり、結果として、ホルダ１６と支持部１８との間のがたつきなくなる。
【００３０】
図６のグラフは、荷落ち防止板１２を収容位置Ｐ０から第２使用位置Ｐ２を超えたある高さまで引き上げたときに発生する下向きの保持力（すなわち、上向きの操作力）の変化を示している。また、逆に、荷落ち防止板１２をその高さから収容位置Ｐ０まで押し下げたときに発生する上向きの保持力（すなわち、下向きの操作力）の変化を示している。
【００３１】
この図６及び前述した図１５との比較から明らかなように、この実施形態においては、スプリング１７の両挟持部２２ａ，２２ｂが開口部２０ａ，２０ｂの内面２３ａ，２３ｂに当接しているため、図１５の隙間Ｔに相当する隙間が存在しない。この点からも、この実施形態において、ホルダ１６とスプリング１７との間、及び、ホルダ１６と支持部１８との間にがたつきが生じないことが明白である。
【００３２】
以上詳述した本実施形態は、下記の各効果を有している。
（１）一対の挟持部２２ａ，２２ｂが一対の係合溝（係合凹部）１９ａ，１９ｂに共に係合した状態において、挟持部（両挟持部２２ａ，２２ｂの一方）２２ａが、開口部２０ａの上側内面（一方の側）２３ａに当接する。かつ、挟持部（両挟持部２２ａ，２２ｂの他方）２２ｂが、開口部２０ｂの下側内面（他方の側）２３ｂに当接する。従って、第１又は第２使用位置Ｐ１，Ｐ２において荷落ち防止板１２が上下方向でがたつくことがなく保持される。
【００３３】
（２）各開口部２０ａ，２０ｂの軸線方向における幅Ｗは、各挟持部２２ａ，２２ｂがその径方向に繰り返し変位するために必要最小限な大きさである。従って、荷落ち防止板１２を第１又は第２使用位置Ｐ１，Ｐ２から移動させるときに、一対の挟持部２２ａ，２２ｂのいずれか一方のみが係合溝１９ａ，１９ｂから外れている状態が発生しない。よって、第１及び第２使用位置Ｐ１，Ｐ２からの高さ調節が円滑に行われる。
【００３４】
（３）両係合溝１９ａ，１９ｂのＶ字状の中心同士を軸線方向に所定値ΔＳ（所定距離）だけ離してスプリング１７の両挟持部２２ａ，２２ｂを軸線方向にずらすのみで、第１及び第２使用位置Ｐ１，Ｐ２での荷落ち防止板１２のがたつきを防止した。このため、がたつき防止用の専用部品等が不要で、部品点数及び組立工数の増加を招かない。
【００３５】
（第２実施形態）
次に、本発明を具体化した第２実施形態を図７に従って説明する。尚、本実施形態は、前記第１実施形態のステー１５における一対の係合溝１９ａ，１９ｂの軸線方向における位置関係と、ホルダ１６における一対の開口部２０ａ，２０ｂの軸線方向における位置関係とを変更したことのみが第１実施形態と異なる。従って、第１実施形態と同じ構成については、符号を同じにしてその説明を省略する。
【００３６】
図７に示すように、一対の係合溝１９ａ，１９ｂは、ステー１５の軸線方向において同じ位置に設けられている。一方、一対の開口部２０ａ，２０ｂは、ホルダ１６の軸線方向において、前記第１実施形態の所定値ΔＳだけずれた位置に設けられている。これにより、両挟持部２２ａ，２２ｂは、一対の係合溝１９ａ，１９ｂに対して係合した状態のときに、挟持部２２ａが開口部２０ａの上側内面２３ａに当接され、挟持部２２ｂが開口部２０ｂの下側内面２３ｂに当接されている。
【００３７】
以上のように構成された本実施形態も、前記第１実施形態と同じ作用をなし、前記第１実施形態の（１）〜（３）に記載の各効果を有する。
（第３実施形態）
次に、本発明を具体化した第３実施形態を図８〜図１１に従って説明する。第１実施形態と同じ構成については、符号を同じにしてその説明を省略し、第１実施形態と異なるスプリング４０、係合溝４１及び開口部４２のみについて詳述する。
【００３８】
図８（ａ），（ｂ）に示すように、係合溝（係合凹部）４１は、支持部１８の外周面１８ａにおいて、その軸線方向における２箇所の所定位置に１つずつ設けられている。
【００３９】
図９（ａ），（ｂ）に示すように、開口部４２は、１箇所に設けられている。開口部４２の両端位置においてホルダ１６には、スプリング４０の両端部４０ａを支持するための一対の係止部４３ａ，４３ｂが一体形成されている。各係止部４３ａ，４３ｂには、スプリング４０の各端部を係止するための係止孔（係止凹部）４４がそれぞれ設けられている。
【００４０】
図１０に示すように、スプリング４０は、断面円形の線状ばね材のみから直線状に形成されている。スプリング４０は、その両端部４０ａが各係止孔４４に係止された状態で、その中央部４０ｂが支持部１８を押圧する。
【００４１】
図１１に示すように、係止孔４４は、その断面形状が、係合溝４１と逆向きのほぼＶ字状に形成されている。このＶ字形状の案内作用により、スプリング４０は、その両端部４０ａが係止孔４４の底部４４ａの中央にそれぞれ押しつけられるとともに、その中央部４０ｂが係合溝４１に押圧される。そして、スプリング４０は、その両端部４０ａが係止孔４４の底部４４ａの中央に押圧されることにより、スプリング４０とホルダ１６との位置関係ががたつきなく定まる。この結果、ホルダ１６と支持部１８との間にがたつきが生じない。
【００４２】
次に、以上のように構成された本実施形態の作用について説明する。
荷落ち防止板１２が第１使用位置Ｐ１又は第２使用位置Ｐ２に配置されると、スプリング４０の中央部４０ｂが係合溝４１に係合して、支持部１８を押圧する。このため、荷落ち防止板１２が第１使用位置Ｐ１又は第２使用位置Ｐ２に保持される。
【００４３】
このとき、スプリング４０の各端部４０ａが各係止孔４４の底部４４ａにそれぞれ押しつけられ、また、中央部４０ｂが係合溝４１に押しつけられていることから、ホルダ１６すなわち荷落ち防止板１２が第１使用位置Ｐ１又は第２使用位置Ｐ２において上下方向にがたつくことなく保持される。
【００４４】
よって、この第３実施形態においても、前述した第１及び第２実施形態の（１），（３）と同様な効果を有する。
（他の実施形態）
次に、上記第１、第２及び第３実施形態以外の実施形態を列記する。
【００４５】
○ 前記第１及び第２実施形態で、支持部１８の軸線を挟んでその両側に設けられた一対の係合溝１９ａ，１９ｂの代わりに、軸線方向における複数位置にそれぞれ周溝を設け、この周溝に一対の挟持部２２ａ，２２ｂが係合する構成とする。この場合にも、前記第１実施形態の（１）〜（３）に記載の各効果がある。
【００４６】
○ 前記第１及び第２実施形態で、略「Ｃ」字状の基部２１を備えたスプリング１７に代えて、ねじりコイルばね状の基部を備えたスプリングを設けた構成とする。この場合にも、前記第１実施形態の（１）〜（３）に記載の各効果がある。
【００４７】
○ 前記第１及び第２実施形態で、１つの線状ばね材のみから形成されたスプリング１７に代えて、例えば、線状ばね材からなる一対の挟持部が、剛体からなる別体の基部ばね部に支持された弾性挟持部材とする。この場合にも、前記第１実施形態の（１），（２）に記載の各効果がある。
【００４８】
○ 前記第１実施形態と第２実施形態とを組み合わせること。すなわち、一対の係合溝１９ａ，１９ｂの軸線方向における位置と、一対の開口部２０ａ，２０ｂの軸線方向における位置とをそれぞれ所定値だけずらした構成とする。このような構成においても、前記第１実施形態の（１）〜（３）に記載の各効果がある。
【００４９】
○ 前記第１〜第３実施形態で、ステー１５は、棒状であれば、角棒でもよい。
○ ホルダ１６と支持部１８のいずれが動いても、あるいは、双方が動いてもよく、要は、ホルダ１６と支持部１８とを相対移動させればよい。
【００５０】
○ 本発明を、図２に示すように、車両用シート１０の背もたれ部３０に対するヘッドレスト３１の高さを調節する位置保持装置３２に具体化してもよい。
【００５１】
【発明の効果】
請求項１〜請求項５に記載の発明によれば、位置調節された保持位置での位置調節方向におけるがたつきをより小さくすることができる。
【図面の簡単な説明】
【図１】第１実施形態の位置保持機構における要部を示す模式断面図。
【図２】位置保持機構を備えた荷落ち防止板が設けられた車両用シートを示す模式斜視図。
【図３】（ａ）は位置保持機構を示す模式正面図、（ｂ）は同じく模式側面図。
【図４】（ａ）は位置保持機構の要部を示す正面図、（ｂ）は同じく側面図。
【図５】図４（ａ）におけるＡ−Ａ線での模式断面図。
【図６】引き上げ時及び押し下げ時における操作力の変化状態を示すグラフ。
【図７】第２実施形態における位置保持機構の要部を示す模式断面図。
【図８】（ａ）は第３実施形態における位置保持機構を示す正面図、（ｂ）は同じく側面図。
【図９】（ａ）は位置保持機構の要部を示す正面図、（ｂ）は同じく側面図。
【図１０】図９（ａ）におけるＣ−Ｃ線での模式断面図。
【図１１】図９（ａ）におけるＤ−Ｄ線での模式断面図。
【図１２】従来の位置保持機構における要部を示す模式縦断面図。
【図１３】同じく模式縦断面図。
【図１４】同じく模式平断面図。
【図１５】両方向での位置調節時における保持力の変化状態を示すグラフ。
【符号の説明】
１０…車両用シート、１１…座部、１２…荷落ち防止部材としての荷落ち防止板、１３…位置保持装置、１４…位置保持機構、１５…ステー、１６…案内部材としてのホルダ、１７…弾性挟持部材としてのスプリング、１８…支持部材としての支持部、１８ａ…外周面、１９ａ，１９ｂ…係合凹部及び部位としての係合溝、２０ａ，２０ｂ…部位としての開口部、２２ａ，２２ｂ…挟持部、２３ａ…（開口部の）内面としての上側内面、２３ｂ…同じく下側内面、４０…スプリング、４０ａ…端部、４０ｂ…中央部、４１…係合凹部としての係合溝、４２…開口部、４３ａ，４３ｂ…係止部、４４…係止凹部としての係止孔、４４ａ…底部。[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a position holding mechanism capable of adjusting a height of a load drop prevention plate provided on a seat portion of a vehicle seat or a headrest also provided on a backrest portion and holding the same at a required position. Things.
[0002]
[Prior art]
For example, the height of a headrest of a vehicle seat is adjusted by a height holding mechanism built in a backrest portion of the vehicle seat, and the headrest is held at a required height.
[0003]
In the conventional height holding mechanism, a stay fixed to a headrest is moved along a guide pipe fixed to a seat back, and a spring supported by the guide pipe is engaged with an engagement groove of the stay. In some cases, the height of the headrest is adjusted (for example, see Patent Documents 1, 2, and 3).
[0004]
As shown in FIGS. 12 to 14, the spring 50 is engaged with any one of the engagement grooves 52 provided at a plurality of positions in the axial direction of the stay 51 so as to sandwich the stay 51 relative to the holder 53. Restrict movement and hold the headrest at the required height.
[0005]
[Patent Document 1]
JP-A-59-171551 (FIGS. 3 to 7)
[Patent Document 2]
Japanese Utility Model Publication No. 62-185556 (FIGS. 3 and 4)
[Patent Document 3]
JP-A-63-52454 (FIGS. 3 and 7)
[0006]
[Problems to be solved by the invention]
As shown in FIG. 13, the spring 50 is disposed in an opening 54 provided in the holder 53. As shown in FIG. 12, the opening 54 has a size as close as possible to the outer diameter R of the spring 50 as long as the width W of the holder 53 in the axial direction does not hinder the elastic deformation of the spring 50. That is, the width W is set to a size obtained by adding the minimum necessary gap T for the spring 50 to smoothly displace in the opening and closing direction to the outer diameter R. This makes it difficult for the holder 53, that is, the headrest, to rattle in the vertical direction.
[0007]
However, if the gap T exists, it is inevitable that the stay 51 rattles by the gap T. That is, as shown in FIG. 15 (graph), when the headrest is disposed at each adjustment position, only the gap T (= WR) between the opening 54 and the spring 50 is retained by the spring 50. Is generated in a range where almost no occurrence occurs. For this reason, in each of the adjustment heights, rattling in the vertical direction by the gap T is inevitable.
[0008]
SUMMARY OF THE INVENTION The present invention has been made to solve the above-described problem, and an object of the present invention is to provide a position holding mechanism capable of reducing backlash in a position adjustment direction at a position where the position is adjusted. It is in.
[0009]
[Means for Solving the Problems]
In order to achieve the above object, the invention according to claim 1 includes a rod-shaped support member, a guide member externally fitted to the support member so as to be relatively movable along the axial direction of the support member, And an elastic holding member capable of elastically holding the support member. At a predetermined position on an outer peripheral surface of the support member, an engagement concave portion with which the elastic holding member can be engaged is provided. The guide member has an opening that can be opposed to the engagement recess. The elastic holding member includes a pair of holding portions that can hold the support member through the opening and engage with the engagement recess. In a state in which the pair of holding portions are engaged with the engagement recesses, one of the holding portions abuts on the inner surface of the opening on one side in the axial direction, and the other of the holding portions is the same as the other. The engaging recess and the opening are provided so as to abut on the inner surface of the opening on the side of.
[0010]
According to the first aspect of the present invention, when the pair of holding portions of the elastic holding member are engaged with the engagement recesses, and the support member and the guide member are held in a predetermined positional relationship, the pair of holding portions have the same configuration. One abuts the inner surface of the opening on one side in the axial direction of the support member, and the other abuts the inner surface of the opening on the other side as well. Therefore, rattling in the axial direction hardly occurs between the support member and the guide member held in a predetermined positional relationship.
[0011]
According to a second aspect of the present invention, in the first aspect of the invention, the size of the opening in the axial direction is a minimum necessary for the holding portion to be displaced in a direction substantially orthogonal to the coaxial line direction. Size.
[0012]
According to the second aspect of the invention, in addition to the operation of the first aspect, when adjusting the positional relationship between the support member and the guide member held in a predetermined positional relationship, a pair of pinching is performed. A state in which only one of the portions is disengaged from the engagement recess does not occur. Therefore, the support member and the guide member are smoothly moved relative to each other from the state where they are maintained in the predetermined positional relationship, and the position is adjusted.
[0013]
According to a third aspect of the present invention, in the first or second aspect, one of the two holding portions abuts on the inner surface of the opening at one side in the axial direction, and the two holding portions are provided. The two portions of the engaging concave portion with which the pair of the holding portions are engaged are substantially V-shaped in cross-section so that the other of the two contacts the inner surface of the opening portion on the other side. It is separated by a predetermined distance in the axial direction.
[0014]
According to the third aspect of the invention, in addition to the function of the first or second aspect of the invention, the pair of holding portions have a substantially V-shaped cross section, and the centers thereof are separated by a predetermined distance in the axial direction. By engaging with both portions of the engagement recess which is separated only by a distance, the engagement recesses are arranged at positions separated from each other by a predetermined distance in the axial direction. As a result, one of the holding portions contacts the inner surface of the opening on one side in the axial direction, and the other of the holding portions also contacts the inner surface of the opening on the other side.
[0015]
According to a fourth aspect of the present invention, in the first aspect or the second aspect of the present invention, the opening portion is configured such that one of the holding portions abuts on the inner surface of the opening portion on one side in the axial direction, And, the inner surfaces of both portions of the opening where the pair of the holding portions are arranged are arranged such that the inner surfaces of the two portions of the opening are arranged at a predetermined distance in the axial direction such that the other of the two holding portions is also in contact with the inner surface of the opening on the other side. Are only displaced. Further, both portions of the engagement concave portion with which the pair of the holding portions are engaged are located at the same position in the axial direction.
[0016]
According to the invention described in claim 4, in addition to the effect of the invention described in claim 1 or 2, the pair of holding portions engage with the engagement recess at the same position in the axial direction. In this state, one of the two holding portions contacts the inner surface of the opening on one side in the axial direction, and the other of the two holding portions also contacts the inner surface of the opening on the other side.
[0017]
According to a fifth aspect of the present invention, there is provided a rod-shaped support member, a guide member externally fitted to the support member so as to be relatively movable along the axial direction of the support member, and held by the guide member and elastically. A substantially rod-shaped spring capable of pressing the support member in a substantially radial direction thereof. At a predetermined position on the outer peripheral surface of the support member, an engagement concave portion with which a central portion of the spring can be engaged is provided. The both ends of the spring are supported by being pressed against the bottom of a substantially V-shaped locking recess provided in the guide member.
[0018]
According to the invention as set forth in claim 5, both ends of the substantially rod-shaped spring are pressed against the bottoms of the engagement recesses by the substantially V-shaped guiding action, and the center portions thereof are engaged with the engagement recesses of the support member. Pressed. For this reason, the positional relationship between the guide member and the support member is fixed, and there is no play between the two.
[0019]
BEST MODE FOR CARRYING OUT THE INVENTION
(1st Embodiment)
Hereinafter, a first embodiment in which the present invention is embodied in a position holding mechanism of a load drop prevention plate provided on a vehicle seat will be described with reference to FIGS.
[0020]
As shown in FIG. 2, the front end of the seat portion 11 of the vehicle seat 10 has a load drop prevention plate () for preventing a load L placed on the seat surface from falling off the seat surface during vehicle deceleration. A load drop prevention member) 12 is provided. The height of the unloading prevention plate 12 in the vertical direction is adjusted to three predetermined heights of the accommodation position P0, the first use position P1, and the second use position P2. The storage position P0 is a position where the unloading prevention plate 12 is not used, as shown by a solid line in FIG. The first use position P1 is a position where the load drop prevention plate 12 is raised from the seat surface by a predetermined height, as also indicated by a two-dot chain line, and the second use position P2 is also higher than the first use position P1. It is also a position raised from the seat surface.
[0021]
Inside the unloading prevention plate 12, a position holding device 13 for holding the unloading prevention plate 12 at the accommodation position P0, the first use position P1, and the second use position P2 is provided. The position holding device 13 includes a pair of left and right position holding mechanisms 14a and 14b. The position holding mechanisms 14a and 14b have the same configuration.
[0022]
As shown in FIGS. 3A and 3B, the position holding mechanism 14 a is fixed to the stay 15 made of a metal bar fixed to the seat 11, the drop prevention plate 12, and is fitted around the stay 15. The holder 16 includes a cylindrical holder (guide member) 16 through which the stay 15 is inserted, and a spring (elastic holding member) 17 held by the holder 16.
[0023]
The stay 15 has a supporting portion (supporting member) 18 that rises in the vertical direction inside the unloading prevention plate 12, and supports the unloading prevention plate 12 on the supporting portion 18. An outer peripheral surface 18a of the support portion 18 is provided with a pair of engaging grooves (engaging concave portions) 19a and 19b each having a V-shaped cross section at two predetermined positions in the axial direction.
[0024]
The spring 17 is engageable with a pair of engagement grooves 19a and 19b. When the spring 17 does not engage with the pair of engagement grooves 19a and 19b, the holder 16 easily moves up and down with respect to the support portion 18. On the other hand, when the spring 17 engages with the pair of engagement grooves 19a and 19b, the holder 16 is held in a predetermined positional relationship with the support portion 18.
[0025]
The spring 17 is a linear spring having a circular cross section, and has a pair of holding portions 22a and 22b extending from both ends of a base 21 having an expanded shape. The spring constant when the spring 17 clamps the support portion 18 between the clamping portions 22a and 22b is set to a small value because the base 21 has a bulging shape so that the entire length can be lengthened.
[0026]
As shown in FIGS. 4A, 4B and 5, the holder 16 is provided with a pair of openings 20a, 20b. The spring 17 is held in the holder 16 by being disposed in the opening portions 20a and 20b at the holding portions 22a and 22b, and is simultaneously supported by the pair of engagement grooves 19a and 19b. 18 is pinched.
[0027]
As shown in FIG. 1, the pair of openings 20 a and 20 b are provided at the same position in the axial direction of the holder 16. The width W of the openings 20a, 20b in the same direction is set to be larger than the outer diameter R of the holding parts 22a, 22b by a predetermined value (for example, 0.2 mm) ΔS. The predetermined value ΔS is the size of the minimum gap required to smoothly displace the holding portions 22a and 22b arranged in the openings 20a and 20b in the radial direction of the holder 16. On the other hand, the center of the V-shape of the pair of engagement grooves 19a and 19b is shifted by the predetermined value ΔS in the axial direction of the support portion 18. Accordingly, in a state where the pair of holding portions 22a and 22b are engaged with the pair of engagement grooves 19a and 19b, the holding portion 22a contacts the upper inner surface 23a of the opening 20a, and the holding portion 22b is opened. 20b is in contact with the lower inner surface 23b. In the drawings, ΔS is drawn large for easy understanding, but actually ΔS is a very small dimension.
[0028]
Next, the operation of the present embodiment configured as described above will be described.
When the unloading prevention plate 12 is pulled up to the first use position P1 or the second use position P2, as shown in FIG. 1, the elasticity of the spring 17 causes the two holding portions 22a and 22b to engage with the pair of engagement grooves 19a and 19b. Engage together. Therefore, the unloading prevention plate 12 is held at the first use position P1 or the second use position P2.
[0029]
In this state, as is clear from FIG. 1, the two holding portions 22a and 22b of the spring 17 are respectively moved to the opening portions 20a and 20b of the holder 16 based on the positional deviation of the engagement grooves 19a and 19b by the predetermined value ΔS. Abut on the inner surfaces 23a and 23b. Therefore, there is no play between the spring 17 and the holder 16, and as a result, there is no play between the holder 16 and the support portion 18.
[0030]
The graph of FIG. 6 shows a change in a downward holding force (that is, an upward operating force) generated when the unloading prevention plate 12 is pulled up from the storage position P0 to a certain height beyond the second use position P2. I have. Conversely, a change in upward holding force (that is, downward operating force) generated when the unloading prevention plate 12 is pushed down from its height to the accommodation position P0 is shown.
[0031]
As is clear from the comparison between FIG. 6 and FIG. 15 described above, in this embodiment, since both holding portions 22a and 22b of the spring 17 are in contact with the inner surfaces 23a and 23b of the openings 20a and 20b, There is no gap corresponding to the gap T in FIG. From this point as well, in this embodiment, it is clear that rattling does not occur between the holder 16 and the spring 17 and between the holder 16 and the support portion 18.
[0032]
The present embodiment described above has the following effects.
(1) In a state where the pair of holding portions 22a and 22b are engaged with the pair of engagement grooves (engaging recesses) 19a and 19b, the holding portion (one of both holding portions 22a and 22b) 22a is opened. Abuts on the upper inner surface (one side) 23a. The holding portion (the other of the holding portions 22a and 22b) 22b abuts on the lower inner surface (the other side) 23b of the opening 20b. Therefore, the unloading prevention plate 12 is held in the first or second use position P1, P2 without rattling in the vertical direction.
[0033]
(2) The width W of each of the openings 20a and 20b in the axial direction is the minimum necessary for each of the holding portions 22a and 22b to be repeatedly displaced in the radial direction. Therefore, when the unloading prevention plate 12 is moved from the first or second use position P1, P2, a state occurs in which only one of the pair of holding portions 22a, 22b is disengaged from the engagement grooves 19a, 19b. do not do. Therefore, height adjustment from the first and second use positions P1 and P2 is performed smoothly.
[0034]
(3) The two V-shaped centers of the engagement grooves 19a and 19b are separated from each other in the axial direction by a predetermined value ΔS (predetermined distance), and the two holding portions 22a and 22b of the spring 17 are merely shifted in the axial direction. In addition, rattling of the unloading prevention plate 12 at the second use positions P1 and P2 is prevented. For this reason, a special part or the like for preventing rattling is not required, and the number of parts and the number of assembling steps are not increased.
[0035]
(2nd Embodiment)
Next, a second embodiment of the present invention will be described with reference to FIG. In this embodiment, the positional relationship between the pair of engaging grooves 19a and 19b in the stay 15 of the first embodiment in the axial direction and the positional relationship between the pair of openings 20a and 20b in the holder 16 in the axial direction are described. Only the change is different from the first embodiment. Therefore, the same components as those in the first embodiment are denoted by the same reference numerals, and description thereof is omitted.
[0036]
As shown in FIG. 7, the pair of engagement grooves 19a and 19b are provided at the same position in the axial direction of the stay 15. On the other hand, the pair of openings 20a and 20b are provided at positions shifted in the axial direction of the holder 16 by the predetermined value ΔS of the first embodiment. Thereby, when the both holding portions 22a and 22b are engaged with the pair of engagement grooves 19a and 19b, the holding portion 22a is brought into contact with the upper inner surface 23a of the opening 20a, and the holding portion 22b is moved. It is in contact with the lower inner surface 23b of the opening 20b.
[0037]
The present embodiment configured as described above also performs the same operation as the first embodiment, and has the effects described in (1) to (3) of the first embodiment.
(Third embodiment)
Next, a third embodiment of the present invention will be described with reference to FIGS. The same components as those in the first embodiment are denoted by the same reference numerals, and description thereof is omitted. Only the spring 40, the engagement groove 41, and the opening 42 different from those in the first embodiment will be described in detail.
[0038]
As shown in FIGS. 8A and 8B, the engagement grooves (engagement concave portions) 41 are provided one by one at two predetermined positions in the axial direction on the outer peripheral surface 18a of the support portion 18. I have.
[0039]
As shown in FIGS. 9A and 9B, the opening 42 is provided at one position. At both ends of the opening 42, the holder 16 is integrally formed with a pair of locking portions 43 a and 43 b for supporting both ends 40 a of the spring 40. Each of the locking portions 43a and 43b is provided with a locking hole (locking recess) 44 for locking each end of the spring 40.
[0040]
As shown in FIG. 10, the spring 40 is formed linearly only from a linear spring material having a circular cross section. The center portion 40b of the spring 40 presses the support portion 18 with both end portions 40a locked in the locking holes 44.
[0041]
As shown in FIG. 11, the locking hole 44 has a substantially V-shaped cross-section opposite to the engagement groove 41. Due to the V-shaped guiding action, both ends 40 a of the spring 40 are pressed against the center of the bottom 44 a of the locking hole 44, and the center 40 b is pressed by the engagement groove 41. When the both ends 40 a of the spring 40 are pressed against the center of the bottom 44 a of the locking hole 44, the positional relationship between the spring 40 and the holder 16 is determined without looseness. As a result, no rattling occurs between the holder 16 and the support portion 18.
[0042]
Next, the operation of the present embodiment configured as described above will be described.
When the unloading prevention plate 12 is disposed at the first use position P1 or the second use position P2, the central portion 40b of the spring 40 engages with the engagement groove 41 and presses the support portion 18. Therefore, the unloading prevention plate 12 is held at the first use position P1 or the second use position P2.
[0043]
At this time, since each end portion 40a of the spring 40 is pressed against the bottom portion 44a of each locking hole 44 and the central portion 40b is pressed against the engaging groove 41, the holder 16, that is, the unloading prevention plate 12 is pressed. Is held in the first use position P1 or the second use position P2 without rattling in the vertical direction.
[0044]
Therefore, the third embodiment has the same effects as (1) and (3) of the first and second embodiments.
(Other embodiments)
Next, embodiments other than the first, second and third embodiments will be listed.
[0045]
In the first and second embodiments, instead of the pair of engagement grooves 19a and 19b provided on both sides of the axis of the support portion 18, circumferential grooves are provided at a plurality of positions in the axial direction. The pair of holding portions 22a and 22b engage with the circumferential groove. Also in this case, there are the respective effects described in (1) to (3) of the first embodiment.
[0046]
In the first and second embodiments, a spring having a torsion coil spring-shaped base is provided in place of the spring 17 having the substantially “C” -shaped base 21. Also in this case, there are the respective effects described in (1) to (3) of the first embodiment.
[0047]
In the first and second embodiments, instead of the spring 17 formed of only one linear spring material, for example, a pair of holding portions made of a linear spring material is a separate base spring made of a rigid body. The elastic holding member is supported by the portion. Also in this case, there are the effects described in (1) and (2) of the first embodiment.
[0048]
○ Combining the first embodiment and the second embodiment. That is, the positions of the pair of engagement grooves 19a and 19b in the axial direction and the positions of the pair of openings 20a and 20b in the axial direction are each shifted by a predetermined value. Even in such a configuration, there are the effects described in (1) to (3) of the first embodiment.
[0049]
In the first to third embodiments, the stay 15 may be a square bar as long as it is rod-shaped.
The holder 16 and the support 18 may be moved, or both may be moved. In short, the holder 16 and the support 18 may be relatively moved.
[0050]
The present invention may be embodied in a position holding device 32 that adjusts the height of the headrest 31 with respect to the backrest 30 of the vehicle seat 10 as shown in FIG.
[0051]
【The invention's effect】
According to the first to fifth aspects of the present invention, it is possible to further reduce backlash in the position adjustment direction at the position where the position is adjusted.
[Brief description of the drawings]
FIG. 1 is a schematic cross-sectional view illustrating a main part of a position holding mechanism according to a first embodiment.
FIG. 2 is a schematic perspective view showing a vehicle seat provided with a load drop prevention plate provided with a position holding mechanism.
3A is a schematic front view showing a position holding mechanism, and FIG. 3B is a schematic side view of the same.
FIG. 4A is a front view showing a main part of a position holding mechanism, and FIG. 4B is a side view of the same.
FIG. 5 is a schematic cross-sectional view taken along line AA in FIG.
FIG. 6 is a graph showing a change state of an operation force at the time of lifting and pressing down.
FIG. 7 is a schematic cross-sectional view illustrating a main part of a position holding mechanism according to a second embodiment.
FIG. 8A is a front view showing a position holding mechanism according to a third embodiment, and FIG. 8B is a side view of the same.
9A is a front view showing a main part of a position holding mechanism, and FIG. 9B is a side view of the same.
FIG. 10 is a schematic sectional view taken along line CC in FIG. 9A.
FIG. 11 is a schematic cross-sectional view taken along line DD in FIG.
FIG. 12 is a schematic longitudinal sectional view showing a main part of a conventional position holding mechanism.
FIG. 13 is a schematic vertical sectional view of the same.
FIG. 14 is a schematic plan sectional view of the same.
FIG. 15 is a graph showing how the holding force changes when the position is adjusted in both directions.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 10 ... Vehicle seat, 11 ... Seat part, 12 ... Unloading prevention plate as an unloading prevention member, 13 ... Position holding device, 14 ... Position holding mechanism, 15 ... Stay, 16 ... Holder as a guide member, 17 ... A spring as an elastic holding member, 18 a support portion as a support member, 18a an outer peripheral surface, 19a and 19b an engagement groove as an engagement recess and a portion, 20a and 20b an opening as a portion, 22a and 22b. Nipping part, 23a ... upper inner surface as inner surface (of opening), 23b ... lower inner surface, 40 ... spring, 40a ... end, 40b ... central part, 41 ... engaging groove as engaging concave part, 42 ... Opening portions, 43a, 43b locking portions, 44 locking holes as locking recesses, 44a bottom portions.

Claims

A rod-shaped support member, a guide member externally fitted to the support member so as to be relatively movable along the axial direction of the support member, and an elastic member held by the guide member and capable of elastically holding the support member. And a holding member,
At a predetermined position on the outer peripheral surface of the support member, an engagement recess engageable with the elastic holding member is provided, and the guide member is provided with an opening capable of facing the engagement recess, The member includes a pair of holding portions that hold the support member through the opening and can be engaged with the engagement recess.
In a state in which the pair of holding portions are engaged with the engagement recesses, one of the holding portions abuts on the inner surface of the opening on one side in the axial direction, and the other of the holding portions is the same as the other. A position holding mechanism in which the engaging recess and the opening are provided so as to abut against the inner surface of the opening on the side of.

2. The position holding mechanism according to claim 1, wherein the size of the opening in the axial direction is substantially the minimum necessary for the holding portion to be displaced in a direction substantially orthogonal to the coaxial direction.

A pair of the holding members is arranged such that one of the holding portions contacts the inner surface of the opening on one side in the axial direction, and the other of the holding portions also contacts the inner surface of the opening on the other side. 3. The position holding device according to claim 1, wherein both portions of the engaging concave portion with which the holding portion engages have a substantially V-shaped cross section, and the centers of both portions are separated by a predetermined distance in the axial direction. 4. mechanism.

The opening is such that one of the holding portions abuts on the inner surface of the opening on one side in the axial direction, and the other of the holding portions abuts on the inner surface of the opening on the other side as well. The engagement recesses are arranged such that the inner surfaces of both portions of the opening where the pair of the holding portions are arranged are displaced by a predetermined distance in the axial direction, and the pair of the holding portions are engaged with each other. 3. The position holding mechanism according to claim 1, wherein the two parts are located at the same position in the axial direction. 4.

A rod-shaped support member, a guide member externally fitted to the support member so as to be relatively movable along the axial direction of the support member, and the support member is held by the guide member and elastically moves the support member substantially in its radial direction. With a substantially bar-shaped spring that can be pressed,
At a predetermined position on the outer peripheral surface of the support member, an engagement concave portion with which a central portion of the spring can be engaged is provided. A position holding mechanism supported by being pressed against the bottom of the stop recess.