JP3777228B2

JP3777228B2 - Pressure relief mechanism for relief valve

Info

Publication number: JP3777228B2
Application number: JP29114996A
Authority: JP
Inventors: 孝明佐星; 健司鈴木
Original assignee: KYB Corp
Current assignee: KYB Corp
Priority date: 1996-10-14
Filing date: 1996-10-14
Publication date: 2006-05-24
Anticipated expiration: 2016-10-14
Also published as: JPH10122401A

Description

【０００１】
【発明の属する技術分野】
この発明は、ブレ−キバルブにおけるリリ−フ弁の昇圧緩衝機構の改良に関するものである。
【０００２】
【従来の技術】
従来、この種のブレ−キバルブにおけるリリ−フ弁の昇圧緩衝機構に関するものとして、例えば、実公昭６２−３１６８１公報の第１図に開示されたものがあり、これについて説明する。
ブレ−キバルブは、ケ−シング内に形成した一対のメイン通路の上流側にカウンタバランス弁を接続し、下流側にはモ−タを接続するとともに、一対のクロスオ−バ形リリ−フ弁を備え、このリリ−弁の流入側をそれぞれのメイン通路に連通し、その流出側を流入側とは反対側のメイン通路に連通し、このリリ−フ弁にはオリフィスを形成し、このオリフィスを介して流入側の圧油をばね室に導入し、リリ−フ弁をオリフィス前後の受圧面積差で作動させるようにしたブレ−キバルブで、リリ−フ弁のばね室周囲に調整ピストンを設け、この調整ピストンの一方の側に区画された空間部を、ばね室が連通するリリ−フ弁の流入側を接続したメイン通路とは別のメイン通路に連通し、他方の側に区画された調整室をばね室に連通し、調整ピストンが空間部側に移動することによってスプリン室の容積を実質的に拡大するように構成されている。
【０００３】
また、実公平４−５１２０２号公報の第３図には、２次圧室と緩衝室とを連通する通路過程に絞りを設ける一方、ショックレスピストンの一端に形成した環状切欠部と、ピストンのストロ−クエンド部分で環状切欠部とオ−バラップする対向部とを備え、ショックレスピストンがストロ−クエンド近傍に達し時、環状切欠部と対向部とが相まって可変絞りを構成したリリ−フ弁の昇降緩衝装置が開示されている。
【０００４】
【発明が解決しようとする課題】
ところで、前記ブレ−キバルブにおけるリリ−フ弁では、ポペットにオリフィスを形成し、このオリフィスを介して流入側の圧油をばね室に導入し、ポペットをオリフィス前後の受圧面積差で作動させるとともに、リリ−フ弁の周囲に設けた調整ピストンに区画される調整室をばね室に連通し、ばね室よりの圧油で調整ピストンが移動することによってばね室の容積を実質的に拡大するようにしてあり、起動時や制動開始時のショックを緩和するという目的は達成されているものの、リリ−フの動特性は、図８に示すように、低圧リリ−フから高圧セット圧に急激に上昇するようになっており、低圧から高圧に昇圧する際の実機における変動が激しく、ポペットに成形したオリフィス径を小さくすることで対応しようとしても、加工上の限界があってオリフィス径を小さくできず、実機でのショックが完全に取れないとい問題があった。
【０００５】
また、リリ−フ弁の昇降緩衝装置では、ショックレスピストンのストロ−クエンド部分で、ダンパ効果が発揮されるので、その時点でリリ−フ弁の制御圧の上昇が低圧から高圧になだらかに昇圧するため、実機でのショックが少ないが、しかし、構造が複雑であり、部品点数が多く、構造が大型になり、コスト高になってしまうと言う問題があった。
【０００６】
そこで、この発明は、リリ−フの動特性が低圧から高圧になだらかに昇圧し、実機でのショックが少なく、構造が簡単で、小形で、耐久性に優れた安価なリリ−フ弁の昇圧緩衝機構を提供することである。
【０００７】
【課題を解決するための手段】
第１の発明では、ケーシングと、ケーシング形成される一次側通路と二次側通路と、一次側通路と二次側通路とを区画するようにケーシングに設けた小径部に嵌着されるシート部材と、ケーシングに螺合するプラグと、一端をシート部材に他端をプラグに係合した保持部材と、保持部材に支持され摺動自在に嵌合するポペットと、ポペットに形成される小径部と、小径部に係合するばね受けと、プラグに形成される段径部に嵌挿されるばね受けと、段径部と保持部材とで形成されるばね室と、ばね室内でばね受けに嵌着されるばねと、ポペットの小径部とばね受けとの間に設けた環状スキマを介してばね室と一次側通路とを連通する連通路と、保持部材の外周に摺動自在に嵌合する調整ピストンと、調整ピストンの一方に区画され二次側通路に連通する空間室と、調整ピストンの他方に区画されるばね室に連通する調整室とを備え、調整ピストンが上記空間室側に移動することによってばね室の容積を拡大してポペットの前後に発生する差圧でシート部の開度を制御するように構成するとともに、前記一次側通路とばね室とを連通する連通過程にポペット弁の小径部と嵌合するばね受けとで形成する環状スキマからなる絞り通路を構成する。
【０００８】
第２の発明では、ケーシングと、ケーシング形成される一次側通路と二次側通路と、一次側通路と二次側通路とを区画するようにケーシングに設けた小径部に嵌着されるシート部材と、ケーシングに螺合するプラグと、一端をシート部材に他端をプラグに係合した保持部材と、保持部材に支持され摺動自在に嵌合するポペットと、ポペットに形成される小径部と、小径部に係合するばね受けと、プラグに形成される段径部に嵌挿されるばね受けと、段径部と保持部材とで形成されるばね室と、ばね室内でばね受けに嵌着されるばねと、ポペットの小径部とばね受けとの間に設けた環状スキマを介してばね室と一次側通路とを連通する連通路と、プラグの先端内径部に形成する環状の凹溝と、この環状の凹溝と保持部材の外周とで形成される室に嵌挿する支持部材とシール部材と、一方の支持部材で区画され二次側通路に連通する空間室と、他方の支持部材で区画さればね室に連通する調整室とを備え、支持部材が上記空間室側に移動することによってばね室の容積を拡大してポペットの前後に発生する差圧でシート部の開度を制御するように構成するとともに前記一次側通路とばね室とを連通する連通路にポペット弁の小径部と嵌合するばね受けとで形成する環状スキマからなる絞り通路を構成する。
【０００９】
第３の発明では、環状の凹溝を保持部材の拡径部に形成し、この環状の凹溝とケ−シングの内径部とで形成される室に支持部材とシ−ル部材とを嵌挿し、一方の支持部材で区画される空間室を二次側通路に連通し、他方の支持部材で区画される調整室とをばね室に連通する。
【００１０】
【発明の実施の形態】
以下、図面に基づいて本発明の実施の形態について説明する。
第１、２図は、第１の実施の形態を示し、第６図はその回路を示したもので、油圧モ−タ１に圧油を供給するメイン通路２、３に一対のクロスオ−バ形リリ−フ弁４、５を設けてある。
【００１１】
このリリ−フ弁４の流入側である一次側をそれぞれのメイン通路３に連通し、その流出側である二次側を一次側とは反対側のメイン通路２に連通し、更に、ブ−スト通路６は、チェック弁７、８を介してメイン通路２、３に接続してある。
【００１２】
リリ−フ弁４は、ケ−シング１１内に形成された一次側通路１２と二次側通路１３とに連通するよう嵌挿されている。
【００１３】
ケ−シング１１に設けられた小径部１４には、シ−ル部材１５であるＯリングでシ−ルされ段径部１６を有するシ−ト部材１７が嵌挿され、一端をシ−ト部材１７の段径部１６に嵌合するとともに他端をケイシング１１にシ−ル部材３９でシ−ルされ螺合されたプラグ３０の段径部３１に係合する保持部材１８が設けられている。
【００１４】
保持部材１８に成形した孔１９にはポペット２０が摺動自在に嵌挿されている。
【００１５】
ポペット２０にはテ−パ部２１が形成され、テ−パ部２１はシ−ト部材１７と係合し、他端に設けた小径部２２にはばね受け２３が嵌合している。
【００１６】
また、ポペット２０の小径部２２には環状の溝２４、通路２５が形成され、この溝２４、通路２５を介してシ−ト部材１７の一次側通路１２と連通されている。
【００１７】
保持部材１８の内径部２６とプラグ３０の段径部３１とからばね室２７が形成され、このばね室２７にはポペット２０の小径部２２に嵌合したばね受け２３とプラク３０の段径部３１にシ−ル部材３２でシ−ルされて嵌挿されるばね受け３３との間にばね２９が装着されて、ポペット２０をシ−ト部材１７に圧接するよう付勢している。
【００１８】
保持部材１８の外周３５とケ−シング１１に設けた大径部３６内を摺動自在に嵌合するようにシ−ル部材３７でシ−ルされた調整ピストン３８が設けられている。
【００１９】
この調整ピストン３８によりケ−シング１１、プラグ３０と保持部材１８とで囲まれる調整室４０とケ−シング１１と保持部材１８とで囲まれる空間室４１とが区画され、調整室４０は保持部材１８に設けた小孔２８を介してばね室２７と連通し、空間室４１は保持部材の外周３５とケ−シングとで形成される隙間４５を介して二次側通路１３に連通している。
【００２０】
プラグ３０には前記ばね２９のばね力を調整する調整部材であるねじ４４が螺合されている。
【００２１】
シ−ト部材１７に臨ませたポペット２０の一次側の受圧面積Ｓ1 に対してばね室２７側の受圧面積Ｓ2 を小さく（Ｓ1 ＞Ｓ2 ）してあり、受圧面積の差（Ｓ1 −Ｓ2 ）で開閉機能を果たすようになっている。
【００２２】
又、前記ポペット２０の小径部２２とばね受け２３とが嵌合する環状スキマｅは、図２に示すように、ポペット２０の小径部２２とばね受け２３の内径２３ａを加工して、両者間に生ずる環状のスキマｅを数ミクロンから３０ミクロンに設定することにより、一次側通路１２とばね室２７とを環状スキマｅ、溝２４、通路２５を介して連通し、通路過程において環状スキマｅによる絞り作用を持たせるようにしてある。
【００２３】
次にその作用について説明する。
今、仮に、一方のメイン通路３に連通する一次側通路１２に圧油が導入され、圧油はポペット２０の通路２５、溝２４を通り、ポペット２０の小径部２２とばね受け２３の孔２３ａとが嵌合する環状スキマｅを経由してばね室２７に流入すると同時に、ポペット２０の作動に伴い、ポペット２０がばね室２７に進入することにより、ばね室２７内の油はばね室２７から小孔２８を通って調整室４０に流入して、調整ピストン３８に作用する。
【００２４】
調整ピストン３８に油圧が作用すると、調整ピストン３８は、空間室４１内の油を隙間４５から二次側通路１３に押し出しながら図中右方向に移動する。
【００２５】
そして、調整ピストン３８が移動すると、調整室４０は拡大され、拡大された容積分がばね室２７の容積を拡大する。
【００２６】
調整ピストン３８が移動して、調整室４０が拡大している間は、ばね室２７には油が流入しており、ポペット２０の前後の一次側通路１２の圧力Ｐ1 とばね室２７内の圧力Ｐ2 との差圧（Ｐ1 −Ｐ2 ）とともに受圧面積差（Ｓ1 −Ｓ2 ）によって、ばね力Ｆに抗してポペット２０が作動し、低圧で開き、低圧リリ−フとして機能し、起動時におけるショックが緩和される。
【００２７】
そして、調整ピストン３８が移動し終わると、一次側通路１２内の圧力Ｐ1 とばね室内の圧力Ｐ2 、調整室４０内の圧力Ｐ3 とが等しくなり、ポペット２０における一次側通路１２における受圧面積Ｓ1 とばね室２７における受圧面積Ｐ2 との受圧面積の差（Ｓ1 −Ｓ2 ）及びスプリングのばね力Ｆによって、ポペット２０がリリ−フの設定圧に移行するため図中右方向に移動するが、その際のポペット２０の移動体積分の油の供給は環状スキマｅによって制御されるため、そのリリ−フ特性は、図７に示すように、低圧から高圧にかけてなだらかに圧力が変化する高圧のリリ−フとして機能することができる。
【００２８】
次に、反対側のメイン通路２に通じる二次側通路１３の圧力Ｐ4 が高圧で、一次側通路１２の圧力Ｐ1 が低圧（Ｐ4 ＞Ｐ1 ）になると、調整ピストン３８には隙間４５から圧油が作用し、調整ピストン３８を図中左方向に移動し、調整室４０の油は小孔２８からばね室２７に流入し、環状スキマｅを通り一次側通路１２に流出して、初期の位置に戻る。
【００２９】
このようにメイン通路３に連通する一次側通路１２とばね室２７とをポペット２０に形成した通路２５、溝２４、並びに小径部２２とばね受け２３の孔２３ａとからなる環状スキマｅを経由してばね室２７に連通するようにしたので、ポペット２０の小径部２２とばね受け２３の孔２３ａを高精度に加工して、環状のスキマｅを数ミクロンから３０ミクロン程度にすることにより、従来のオリフィス径では加工上の限界があって加工できない絞り開口を形成することができるため、調整室４０の容量も小さくて良く、その分調整ピストン３８のストロ−クを小さくでき、ポペット２０の小径部２２とばね受け２３の孔２３ａとの環状のスキマｅを適宜に設定することにより、リリ−フの動特性を低圧から高圧になだらかに昇圧させ、実機でのショックが少なく、しかも構造が簡単で、耐久性に優れたリリ−フ弁の昇圧緩衝機構を提供できる。
【００３０】
第３図に示す第２の実施の形態は、リリ−フ弁の外周に設けた調整ピストンの構成のみを実施例と相違させたもので、その他は第１の実施例と同じであり、そこで、相違する構成についてのみ説明し、他の構成要素の詳細については省略する。
【００３１】
そこで、第２の実施の形態のリリ−フ弁４、５では、ケ−シング１１内にシ−ル部材３９でシ−ルされて螺合、嵌挿されるプラグ３０の内径部５０に環状の凹溝５１を形成し、図４に示すように、この環状の凹溝５１と保持部材１８の外周３５とで環状室５２が形成され、この環状室５２に支持部材部であるバックアップリング５３、５４とシ−ル部材であるＯリング５５が装着されており、プラグ３０と保持部材１８との係合部５６でのシ−ルをも兼ねている。
【００３２】
環状室５２に圧油が作用するとき、環状室５２に装着したＯリング５５が圧縮されて、環状室５２内のバックアップリング５３との間に調整室５７あるいは空間室５８を形成するようにしてあり、調整室５７はプラグ３０と保持部材１８との係合隙間６０と保持部材１８に設けた小孔２８を介してばね室２７と連通し、空間室５８はプラグ３０と保持部材１８との隙間６１より二次側通路１３に連通するようにしてある。
【００３３】
メイン通路３に連通する一次側通路１２に圧油が導入されると、圧油はポペット２０の通路２５、溝２４を通り、ポペット２０の小径部２２とばね受け２３の孔２３ａとが嵌合する環状スキマｅを経由してばね室２７に流入すると同時に、ばね室２７から小孔２８、隙間６０を通って調整室５７に流入して、Ｏリング５５、バックアップリング５３に作用する。
【００３４】
Ｏリング５５に油圧が作用すると、圧縮されながら図中右方向に移動する。
【００３５】
そして、、バックアップリング５３、Ｏリング５５が移動すると、調整室５７は拡大され、拡大された容積分がばね室２７の容積を拡大する。
【００３６】
バックアップリング５３、Ｏリング５５が移動して、調整室５７が拡大している間は、ばね室２７には油が流入しており、ポペット２０の前後のばね室内の圧力Ｐ2 と一次側通路内の圧力Ｐ1 との差圧（Ｐ1 −Ｐ2 ）とともに受圧面積差（Ｓ1 −Ｓ2 ）によって、ばね力Ｆに抗してポペット２０が作動し、低圧で開き、低圧リリ−フとして機能し、起動時におけるショックが緩和される。
【００３７】
そして、バックアップリング５３、Ｏリング５５が移動し終わると、一次側通路１２内の圧力Ｐ1 とばね室内の圧力Ｐ2 、調整室５７内の圧力Ｐ3 とが等しくなり、ポペット２０における一次側通路１２における受圧面積Ｓ1 とばね室における受圧面積Ｓ2 との受圧面積の差（Ｓ1 −Ｓ2 ）及びスプリングのばね力Ｆによって、ポペット２０がリリ−フの設定圧に移行するため、図中右方向に移動するが、その際のポペット２０の移動体積分の油の供給は環状スキマｅによって制御されるため、リリ−フ特性は、図７に示すように、低圧から高圧にかけてなだらかに圧力が変化する高圧のリリ−フとして機能する。
【００３８】
このように、プラグ３０の内径部５０に環状の凹溝５１を形成し、この環状の凹溝５１と保持部材１８の外周３５とで環状室５２が形成され、この環状室５２にバックアップリング５３、５４とシ−ル部材であるＯリング５５を装着し、プラグ３０と保持部材１８との係合部５６をシ−ルするとともに、この環状室５２に圧油が作用するとき、環状室５２に装着したＯリング５５が圧縮されて、環状室５２内にバックアップリング５３、５４との間に調整室５７と空間室５８とを形成し、調整室５７はプラグ３０と保持部材１８との係合隙間６０と保持部材１８に設けた小孔２８を介してばね室２７と連通し、空間室５８はプラグ３０と保持部材１８との隙間６１より二次側通路１３に連通するようにしたので、前記第１の実施例における保持部材１８の外周３５を摺動する調整ピストン３８を必要とせずに同じ効果が得られ、しかも、その分、部品点数を削減でき、安価にできる。
【００３９】
さらに、第５図に示す第３の実施の形態は、前記第２の実施の形態と同様、リリ−フ弁の外周に設けた調整ピストンに相当する構成のみを実施例と相違させたもので、その他は第１の実施例と同じであり、そこで、相違する構成についてのみ説明し、他の構成要素の詳細については省略する。
【００４０】
第３の実施の形態のリリ−フ弁４、５では、保持部材１８の拡径部６５に環状の凹溝５１を形成し、この環状の凹溝５１とケ−シング１１の内径部６６とで形成される環状室６７に支持部材であるバックアップリン５３、５４とシ−ル部材であるＯリング５５とを嵌挿し、環状室６７内での一方のバックアップリン５３で区画される調整室７０をケ−シング１１の内径部６６と保持部材１８の拡径部６５との隙間７３及び小孔２８を介してばね室２７に連通し、他方のバックアップリング５４で区画される空間室７１をケ−シング１１の内径部６６と保持部材１８の拡径部６５との隙間７４を介して、二次側通路１３に連通するようにしたもので、ケ−シング１１の内径部６６と保持部材１８との係合部６８のシ−ルをも兼ねるようにしている。これにより、保持部材１８と係合するプラグ３０の形状を小さくできるとともに嵌挿するケ−シング１１の内径部６６も小さくなり、ケ−シング１１を小形、軽量にすることができる。
【００４１】
尚、その作用については前記第２の実施例と同様なので、詳細については省略する。
【００４２】
【発明の効果】
第１の発明によれば、メイン通路に連通する一次側通路とばね室とをポペットに形成した通路、溝、並びに小径部とばね受けの内径とからなる環状スキマｅを経由してばね室に連通するようにしたので、ポペットの小径部とばね受けの内径を高精度に加工することにより従来のオリフィス径では加工上の限界があって加工できない絞り開口を形成することができるため、調整室の容量も小さくて良く、その分調整ピストンのストロ−クを小さくでき、ポペットの小径部とばね受けの内径との環状のスキマを適宜に設定することにより、リリ−フの動特性を低圧から高圧になだらかに昇圧させ、実機でのショックが少なく、しかも構造が簡単で、耐久性に優れたリリ−フ弁の昇圧緩衝機構を提供できる。
【００４３】
第２の発明によれば、プラグの内径部に環状の凹溝を形成し、この環状の凹溝と保持部材の外周とで環状室が形成され、この環状室にバックアップリングとシ−ル部材であるＯリングを装着し、プラグと保持部材との係合部をシ−ルするとともに、この環状室に圧油が作用するとき、環状室に装着したＯリングが圧縮されて、環状室内にバックアップリングとの間に調整室と空間室とを形成し、調整室はプラグと保持部材との係合隙間と保持部材に設けた小孔を介してばね室と連通し、空間室はプラグと保持部材との隙間より二次側通路に連通するようにしたので、前記第１の実施例における保持部材の外周を摺動する調整ピストンを必要とせずに同じ効果が得られ、しかも、その分、部品点数を削減でき、安価にできる。
【００４４】
第３の発明によれば、保持部材の拡径部に環状の凹溝を形成し、この環状の凹溝とケ−シングの内径部とで形成される環状室に支持部材であるバックアップリンとシ−ル部材であるＯリングとを嵌挿し、環状室内での一方のバックアップリンで区画される調整室をケ−シングの内径部と保持部材の拡径部と
の隙間及び小
孔を介してばね室に連通し、他方のバックアップリンで区画される空間室をケ−シングの内径部と保持部材の拡径部との隙間を介して、二次側通路に連通するようにしたので、保持部材と係合するプラグの形状を小さくできるとともに嵌挿するケ−シングの内径部も小さくなり、ケ−シングを小形、軽量にすることができる。
【図面の簡単な説明】
【図１】この発明の実施の形態を示すリリ−フ弁の昇圧緩衝機構の縦断面図である。
【図２】同じく図１におけるＡ部拡大断面図である。
【図３】同じく第２の実施の形態を示すリリ−フ弁の昇圧緩衝機構の縦断面図である。
【図４】同じく同じく図３におけるＢ部拡大断面図である。
【図５】同じく第３の実施の形態を示すリリ−フ弁の昇圧緩衝機構の縦断面図である。
【図６】同じく油圧回路図である。
【図７】同じくリリ−フ弁の動特性を説明する説明図である。
【図８】従来例のリリ−フ弁の動特性を説明する説明図である。
【符号の説明】
１油圧モ−タ
２、３メイン通路
４、５リリ−フ弁
６ブ−スト通路
７、８チェック弁
１１ケ−シング
１２一次側通路
１３二次側通路
１４小径部
１５シ−ル部材
１６段径部
１７シ−ト部材
１８保持部材
１９孔
２０ポペット
２１テ−パ部
２２小径部
２３ばね受け
２３ａ孔
２４溝
２５通路
２６内径部
２７ばね室
２８小孔
２９ばね
３０プラグ
３１段径部
３２シ−ル部材
３３ばね受け
３５外周
３６大径部
３７シ−ル部材
３８調整ピストン
３９シ−ル部材
４０調整室
４２空間室
４４ねじ
４５隙間
５１環状の凹溝
５２環状室
５３、５４支持部材
５５シ−ル部材
５６係合部
５７調整室
５８空間室
６０、６１隙間
６５拡径部
６６内径部
６８係合部
７０調整室
７１空間室
７３、７４隙間
ｅ環状のスキマ
Ｆばね力
Ｐ1 一次側通路内の圧力
Ｐ2 ばね室内の圧力
Ｐ3 調整室内の圧力
Ｐ4 二次側通路内の圧力
Ｓ1 受圧面積
Ｓ2 受圧面積[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an improvement of a pressure rising buffer mechanism of a relief valve in a brake valve.
[0002]
[Prior art]
2. Description of the Related Art Conventionally, there has been disclosed, for example, in FIG. 1 of Japanese Utility Model Publication No. 62-31681, as to a pressure relief buffer mechanism for a relief valve in this type of brake valve.
The brake valve has a counter balance valve connected to the upstream side of a pair of main passages formed in the casing, a motor connected to the downstream side, and a pair of crossover type relief valves. The relief valve has an inflow side communicated with each main passage, an outflow side communicated with a main passage opposite to the inflow side, and an orifice is formed in the relief valve. Pressure valve on the inflow side is introduced into the spring chamber, and the relief valve is operated with the pressure receiving area difference between the front and rear of the orifice. An adjustment piston is provided around the spring chamber of the relief valve, The adjustment section divided on one side of the adjustment piston is connected to a main passage different from the main passage connecting the inflow side of the relief valve to which the spring chamber communicates, and is divided on the other side. Connect the chamber to the spring chamber and adjust the piston There has been configured to substantially expand the volume of the springback chamber by moving into the space side.
[0003]
In FIG. 3 of Japanese Utility Model Publication No. 4-51202, a throttle is provided in the passage process that connects the secondary pressure chamber and the buffer chamber, while an annular notch formed at one end of the shockless piston, The relief valve has an annular notch at the stroke end and an opposing part that overlaps. When the shockless piston reaches the vicinity of the stroke end, the annular notch and the opposite part combine to form a variable throttle. An elevator cushioning device is disclosed.
[0004]
[Problems to be solved by the invention]
By the way, in the relief valve in the brake valve, an orifice is formed in the poppet, pressure oil on the inflow side is introduced into the spring chamber through the orifice, and the poppet is operated by a pressure receiving area difference before and after the orifice. An adjustment chamber defined by an adjustment piston provided around the relief valve communicates with the spring chamber, and the adjustment piston moves by pressure oil from the spring chamber so that the volume of the spring chamber is substantially enlarged. Although the purpose of mitigating shock at start-up or braking start has been achieved, the dynamic characteristics of the relief increases rapidly from the low pressure relief to the high pressure set pressure as shown in FIG. Fluctuations in the actual machine when boosting from low pressure to high pressure are severe, and even if you try to cope by reducing the diameter of the orifice formed in the poppet, there are limitations on processing Not possible to reduce the orifice size if there was a shock had not fully take problems in actual.
[0005]
In addition, in the lift buffering device of the relief valve, the damper effect is exhibited at the stroke end portion of the shockless piston, so that the increase in the control pressure of the relief valve gradually increases from low pressure to high pressure at that time. Therefore, there is little shock in the actual machine, but there is a problem that the structure is complicated, the number of parts is large, the structure is large, and the cost is high.
[0006]
In view of this, the present invention provides a relief valve whose pressure is increased smoothly from low pressure to high pressure, has little shock in the actual machine, has a simple structure, is compact, and has excellent durability. It is to provide a buffering mechanism.
[0007]
[Means for Solving the Problems]
In the first invention, a casing, a sheet member that is fitted into a small-diameter portion provided in the casing so as to partition the primary side passage and the secondary side passage formed, and the primary side passage and the secondary side passage are formed. A plug screwed into the casing, a holding member with one end engaged with the sheet member and the other end engaged with the plug, a poppet supported by the holding member and slidably fitted, and a small diameter portion formed on the poppet A spring receiver that engages with the small diameter portion, a spring receiver that is inserted into the step diameter portion formed on the plug, a spring chamber that is formed by the step diameter portion and the holding member, and a spring receiver that fits within the spring chamber. Adjustment to be slidably fitted to the outer periphery of the holding member, a communication passage communicating the spring chamber and the primary passage through an annular gap provided between the small diameter portion of the poppet and the spring receiver The secondary passage is divided into one of the piston and adjustment piston A space chamber that communicates with an adjustment chamber that communicates with the spring chamber defined on the other side of the adjustment piston, and the adjustment piston moves toward the space chamber to increase the volume of the spring chamber and is generated before and after the poppet. And the opening of the seat portion is controlled by the differential pressure, and the annular clearance formed by the spring receiver fitted to the small diameter portion of the poppet valve in the communication process of communicating the primary side passage and the spring chamber. A throttle passage is formed.
[0008]
In the second invention, a casing, a sheet member that is fitted into a small-diameter portion provided in the casing so as to partition the primary side passage and the secondary side passage formed, and the primary side passage and the secondary side passage are formed. A plug screwed into the casing, a holding member with one end engaged with the sheet member and the other end engaged with the plug, a poppet supported by the holding member and slidably fitted, and a small diameter portion formed on the poppet A spring receiver that engages with the small diameter portion, a spring receiver that is inserted into the step diameter portion formed on the plug, a spring chamber that is formed by the step diameter portion and the holding member, and a spring receiver that fits within the spring chamber. A communication passage that communicates the spring chamber with the primary passage through an annular gap provided between the small diameter portion of the poppet and the spring receiver, and an annular concave groove formed in the tip inner diameter portion of the plug A chamber formed by the annular groove and the outer periphery of the holding member A support member to be inserted and a seal member; a space chamber defined by one support member and communicated with the secondary passage; and an adjustment chamber defined by the other support member and communicated with the spring chamber; By moving to the space chamber side, the volume of the spring chamber is enlarged so that the opening of the seat portion is controlled by the differential pressure generated before and after the poppet, and the communication between the primary passage and the spring chamber is established. A throttle passage formed by an annular gap formed by a small diameter portion of the poppet valve and a spring receiver fitted in the passage is configured.
[0009]
In the third invention, an annular groove is formed in the enlarged diameter portion of the holding member, and the support member and the seal member are fitted in a chamber formed by the annular groove and the inner diameter portion of the casing. The space chamber defined by one of the support members communicates with the secondary passage, and the adjustment chamber defined by the other support member communicates with the spring chamber.
[0010]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to the drawings.
FIGS. 1 and 2 show the first embodiment, and FIG. 6 shows the circuit thereof. A pair of crossovers are provided in main passages 2 and 3 for supplying pressure oil to the hydraulic motor 1. Form relief valves 4 and 5 are provided.
[0011]
The primary side which is the inflow side of the relief valve 4 is communicated with each main passage 3, the secondary side which is the outflow side is communicated with the main passage 2 opposite to the primary side, and the The strike passage 6 is connected to the main passages 2 and 3 via check valves 7 and 8.
[0012]
The relief valve 4 is fitted and inserted so as to communicate with a primary side passage 12 and a secondary side passage 13 formed in the casing 11.
[0013]
The small diameter portion 14 provided in the casing 11 is fitted with a sheet member 17 having a step diameter portion 16 which is sealed by an O-ring which is a seal member 15, and one end of the sheet member is the sheet member. A holding member 18 is provided that engages with the step diameter portion 16 of the plug 30 that is fitted to the step diameter portion 16 of the 17 and sealed with the sealing member 39 at the other end by the seal member 39. .
[0014]
A poppet 20 is slidably inserted into a hole 19 formed in the holding member 18.
[0015]
A taper portion 21 is formed in the poppet 20, the taper portion 21 is engaged with the sheet member 17, and a spring receiver 23 is fitted in a small diameter portion 22 provided at the other end.
[0016]
An annular groove 24 and a passage 25 are formed in the small diameter portion 22 of the poppet 20, and communicated with the primary passage 12 of the sheet member 17 through the groove 24 and the passage 25.
[0017]
A spring chamber 27 is formed from the inner diameter portion 26 of the holding member 18 and the step diameter portion 31 of the plug 30. The spring chamber 27 has a spring receiver 23 fitted to the small diameter portion 22 of the poppet 20 and a step diameter portion of the plaque 30. A spring 29 is mounted between a spring receiver 33 which is sealed by 31 and sealed with a seal member 32, and urges the poppet 20 to come into pressure contact with the sheet member 17.
[0018]
An adjustment piston 38 sealed by a seal member 37 is provided so that the outer periphery 35 of the holding member 18 and the inside of the large diameter portion 36 provided in the casing 11 are slidably fitted.
[0019]
The adjustment piston 38 partitions the adjustment chamber 40 surrounded by the casing 11, the plug 30 and the holding member 18, and the space chamber 41 surrounded by the casing 11 and the holding member 18. 18 communicates with the spring chamber 27 through a small hole 28 provided in the space 18, and the space chamber 41 communicates with the secondary passage 13 through a gap 45 formed by the outer periphery 35 of the holding member and the casing. .
[0020]
The plug 30 is screwed with a screw 44 that is an adjustment member for adjusting the spring force of the spring 29.
[0021]
The pressure receiving area S2 on the spring chamber 27 side is smaller than the pressure receiving area S1 on the primary side of the poppet 20 facing the sheet member 17 (S1> S2), and the difference in pressure receiving area (S1-S2) It is designed to open and close.
[0022]
Further, as shown in FIG. 2, the annular gap e in which the small diameter portion 22 of the poppet 20 and the spring receiver 23 are fitted is formed by processing the small diameter portion 22 of the poppet 20 and the inner diameter 23a of the spring receiver 23. Is set to several to 30 microns, the primary passage 12 and the spring chamber 27 are communicated with each other via the annular gap e, the groove 24, and the passage 25. It has a squeezing action.
[0023]
Next, the operation will be described.
Now, temporarily, pressure oil is introduced into the primary side passage 12 communicating with one main passage 3, and the pressure oil passes through the passage 25 and the groove 24 of the poppet 20, and the hole 22 a of the small diameter portion 22 of the poppet 20 and the spring receiver 23. Flows into the spring chamber 27 via the annular gap e that engages with the poppet 20, and at the same time, the poppet 20 enters the spring chamber 27 as the poppet 20 operates, so that the oil in the spring chamber 27 flows from the spring chamber 27. It flows into the adjustment chamber 40 through the small hole 28 and acts on the adjustment piston 38.
[0024]
When hydraulic pressure acts on the adjustment piston 38, the adjustment piston 38 moves rightward in the figure while pushing oil in the space chamber 41 from the gap 45 to the secondary side passage 13.
[0025]
When the adjustment piston 38 moves, the adjustment chamber 40 is expanded, and the expanded volume increases the volume of the spring chamber 27.
[0026]
While the adjustment piston 38 moves and the adjustment chamber 40 is expanded, oil flows into the spring chamber 27, and the pressure P 1 in the primary passage 12 before and after the poppet 20 and the pressure in the spring chamber 27. The poppet 20 operates against the spring force F, opens at a low pressure, functions as a low pressure relief by the pressure difference (P1 -P2) with the pressure difference (P1 -P2) with P2, and acts as a low pressure relief. Is alleviated.
[0027]
When the adjustment piston 38 finishes moving, the pressure P1 in the primary passage 12, the pressure P2 in the spring chamber, and the pressure P3 in the adjustment chamber 40 become equal, and the pressure receiving area S1 in the primary passage 12 in the poppet 20 The poppet 20 moves to the right in the drawing in order to shift to the set pressure of the relief by the difference (S1 -S2) of the pressure receiving area with the pressure receiving area P2 in the spring chamber 27 and the spring force F of the spring. Since the supply of the oil corresponding to the moving volume of the poppet 20 is controlled by the annular skimmer e, the relief characteristic is as shown in FIG. 7 of the high pressure relief where the pressure gradually changes from low pressure to high pressure. Can function as.
[0028]
Next, when the pressure P4 of the secondary passage 13 leading to the opposite main passage 2 is high and the pressure P1 of the primary passage 12 is low (P4> P1), the adjustment piston 38 is pressurized with pressure oil from the gap 45. Acts to move the adjusting piston 38 in the left direction in the figure, and the oil in the adjusting chamber 40 flows into the spring chamber 27 from the small hole 28, flows out through the annular skimmer e, and flows out into the primary side passage 12. Return to.
[0029]
In this way, the primary side passage 12 communicating with the main passage 3 and the spring chamber 27 pass through the passage 25 formed in the poppet 20, the groove 24, and the annular gap e composed of the small diameter portion 22 and the hole 23 a of the spring receiver 23. Since the small diameter portion 22 of the poppet 20 and the hole 23a of the spring receiver 23 are processed with high accuracy so that the annular gap e is changed from several microns to 30 microns, With the orifice diameter of this, there can be formed a throttle opening that cannot be machined due to processing limitations, so the capacity of the adjustment chamber 40 can be small, and the stroke of the adjustment piston 38 can be reduced correspondingly, and the small diameter of the poppet 20 can be reduced. By appropriately setting the annular clearance e between the portion 22 and the hole 23a of the spring receiver 23, the dynamic characteristic of the relief is gently increased from low pressure to high pressure. Yokku less, yet has a simple structure, excellent Lili durability - can provide a boost cushioning mechanism off valve.
[0030]
The second embodiment shown in FIG. 3 differs from the first embodiment only in the configuration of the adjustment piston provided on the outer periphery of the relief valve, and the other parts are the same as the first embodiment. Only different configurations will be described, and details of other components will be omitted.
[0031]
Therefore, in the relief valves 4 and 5 according to the second embodiment, an annular inner diameter portion 50 of the plug 30 is sealed in the casing 11 by the seal member 39 and screwed and inserted. A concave groove 51 is formed, and as shown in FIG. 4, an annular chamber 52 is formed by the annular concave groove 51 and the outer periphery 35 of the holding member 18, and a backup ring 53 that is a support member portion is formed in the annular chamber 52. 54 and an O-ring 55 which is a seal member are mounted, and also serves as a seal at the engaging portion 56 between the plug 30 and the holding member 18.
[0032]
When pressure oil acts on the annular chamber 52, the O-ring 55 attached to the annular chamber 52 is compressed to form an adjustment chamber 57 or a space chamber 58 with the backup ring 53 in the annular chamber 52. The adjusting chamber 57 communicates with the spring chamber 27 through the engagement gap 60 between the plug 30 and the holding member 18 and the small hole 28 provided in the holding member 18, and the space chamber 58 is connected to the plug 30 and the holding member 18. The gap 61 communicates with the secondary passage 13.
[0033]
When pressure oil is introduced into the primary side passage 12 communicating with the main passage 3, the pressure oil passes through the passage 25 and the groove 24 of the poppet 20, and the small diameter portion 22 of the poppet 20 and the hole 23a of the spring receiver 23 are fitted. At the same time, it flows into the spring chamber 27 via the annular gap e and flows into the adjustment chamber 57 from the spring chamber 27 through the small hole 28 and the gap 60 and acts on the O-ring 55 and the backup ring 53.
[0034]
When hydraulic pressure acts on the O-ring 55, it moves in the right direction in the figure while being compressed.
[0035]
Then, when the backup ring 53 and the O-ring 55 move, the adjustment chamber 57 is expanded, and the expanded volume increases the volume of the spring chamber 27.
[0036]
While the backup ring 53 and the O-ring 55 are moved and the adjustment chamber 57 is enlarged, oil flows into the spring chamber 27, and the pressure P 2 in the spring chamber before and after the poppet 20 and the primary passage Due to the pressure difference (S1 -S2) with the differential pressure (P1 -P2) from the pressure P1, the poppet 20 operates against the spring force F, opens at a low pressure, functions as a low pressure relief, and is activated The shock at is alleviated.
[0037]
When the backup ring 53 and the O-ring 55 have finished moving, the pressure P1 in the primary side passage 12, the pressure P2 in the spring chamber, and the pressure P3 in the adjustment chamber 57 become equal to each other in the primary passage 12 in the poppet 20. The poppet 20 shifts to the set pressure of the relief due to the difference (S1 -S2) in the pressure receiving area between the pressure receiving area S1 and the pressure receiving area S2 in the spring chamber and the spring force F of the spring. However, since the oil supply for the moving volume of the poppet 20 at that time is controlled by the annular skimmer e, the relief characteristic is a high pressure in which the pressure gradually changes from low pressure to high pressure as shown in FIG. Functions as a relief.
[0038]
Thus, the annular groove 51 is formed in the inner diameter portion 50 of the plug 30, and the annular chamber 52 is formed by the annular groove 51 and the outer periphery 35 of the holding member 18, and the backup ring 53 is formed in the annular chamber 52. , 54 and an O-ring 55 which is a seal member, and the engagement portion 56 between the plug 30 and the holding member 18 is sealed, and when the pressure oil acts on the annular chamber 52, the annular chamber 52 The O-ring 55 attached to the compression ring is compressed to form an adjustment chamber 57 and a space chamber 58 between the backup rings 53 and 54 in the annular chamber 52, and the adjustment chamber 57 is connected to the plug 30 and the holding member 18. Since the joint chamber 60 communicates with the spring chamber 27 through the small hole 28 provided in the holding member 18, the space chamber 58 communicates with the secondary side passage 13 through the gap 61 between the plug 30 and the holding member 18. , The protection in the first embodiment. The same effect without the need for adjustment piston 38 which slides to obtain the outer periphery 35 of the member 18, moreover, correspondingly, the number of parts can be reduced, can be inexpensive.
[0039]
Furthermore, the third embodiment shown in FIG. 5 differs from the embodiment only in the configuration corresponding to the adjustment piston provided on the outer periphery of the relief valve, as in the second embodiment. The other components are the same as those of the first embodiment. Therefore, only different components will be described, and details of other components will be omitted.
[0040]
In the relief valves 4 and 5 of the third embodiment, an annular concave groove 51 is formed in the enlarged diameter portion 65 of the holding member 18, and the annular concave groove 51 and the inner diameter portion 66 of the casing 11 are formed. A back-up ring 53, 54 as a support member and an O-ring 55 as a seal member are fitted and inserted into an annular chamber 67 formed by the adjustment chamber 70 defined by one back-up ring 53 in the annular chamber 67. Is connected to the spring chamber 27 through a gap 73 and a small hole 28 between the inner diameter portion 66 of the casing 11 and the enlarged diameter portion 65 of the holding member 18, and the space chamber 71 defined by the other backup ring 54 is sealed. -It communicates with the secondary side passage 13 through a gap 74 between the inner diameter portion 66 of the casing 11 and the enlarged diameter portion 65 of the holding member 18, and the inner diameter portion 66 of the casing 11 and the holding member 18 are communicated with each other. Also serves as a seal for the engaging portion 68 . As a result, the shape of the plug 30 engaged with the holding member 18 can be reduced, and the inner diameter portion 66 of the case 11 to be inserted can be reduced, so that the case 11 can be made smaller and lighter.
[0041]
Since the operation is the same as that of the second embodiment, the details are omitted.
[0042]
【The invention's effect】
According to the first aspect of the present invention, the spring chamber is formed via the passage formed by forming the primary passage and the spring chamber in communication with the main passage and the spring chamber, the groove, and the annular gap e composed of the small diameter portion and the inner diameter of the spring receiver. Because it is in communication, the aperture of the small diameter part of the poppet and the inner diameter of the spring receiver can be processed with high precision, so that it is possible to form a throttle opening that cannot be processed with the conventional orifice diameter. The stroke of the adjustment piston can be reduced accordingly, and the dynamic characteristics of the relief can be reduced from low pressure by appropriately setting the annular clearance between the small diameter part of the poppet and the inner diameter of the spring receiver. It is possible to provide a pressure relief mechanism for a relief valve that is gently increased to a high pressure, has little shock in an actual machine, has a simple structure, and has excellent durability.
[0043]
According to the second invention, an annular concave groove is formed in the inner diameter portion of the plug, and an annular chamber is formed by the annular concave groove and the outer periphery of the holding member. The backup ring and the seal member are formed in the annular chamber. Is attached to seal the engaging portion between the plug and the holding member, and when pressure oil acts on the annular chamber, the O-ring attached to the annular chamber is compressed, An adjustment chamber and a space chamber are formed between the backup ring and the adjustment chamber. The adjustment chamber communicates with the spring chamber via an engagement gap between the plug and the holding member and a small hole provided in the holding member. Since the secondary passage is communicated with the holding member through the gap, the same effect can be obtained without the need for the adjustment piston that slides on the outer periphery of the holding member in the first embodiment. The number of parts can be reduced and the cost can be reduced.
[0044]
According to the third aspect of the present invention, the annular groove is formed in the enlarged diameter portion of the holding member, and the backup phosphorus as the support member is formed in the annular chamber formed by the annular groove and the inner diameter portion of the casing. An O-ring that is a seal member is inserted and an adjustment chamber defined by one backup ring in the annular chamber is inserted through a gap and a small hole between the inner diameter portion of the casing and the expanded diameter portion of the holding member. The space chamber communicated with the spring chamber and communicated with the secondary side passage through the gap between the inner diameter portion of the casing and the enlarged diameter portion of the holding member is held. The shape of the plug engaged with the member can be reduced, and the inner diameter portion of the casing to be inserted can be reduced, so that the casing can be reduced in size and weight.
[Brief description of the drawings]
FIG. 1 is a longitudinal sectional view of a booster buffer mechanism for a relief valve according to an embodiment of the present invention.
2 is an enlarged cross-sectional view of a part A in FIG.
FIG. 3 is a longitudinal sectional view of a boost buffer mechanism for a relief valve, also showing a second embodiment.
4 is an enlarged cross-sectional view of a portion B in FIG. 3 in the same manner.
FIG. 5 is a longitudinal sectional view of a boost buffer mechanism for a relief valve, similarly showing a third embodiment.
FIG. 6 is a hydraulic circuit diagram.
FIG. 7 is an explanatory view for explaining the dynamic characteristics of the relief valve.
FIG. 8 is an explanatory diagram for explaining the dynamic characteristics of a conventional relief valve.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Hydraulic motor 2, 3 Main passage 4, 5 Relief valve 6 Boost passage 7, 8 Check valve 11 Case 12 Primary side passage 13 Secondary side passage 14 Small diameter part 15 Seal member 16 steps Diameter portion 17 Sheet member 18 Holding member 19 Hole 20 Poppet 21 Taper portion 22 Small diameter portion 23 Spring receiver 23a Hole 24 Groove 25 Passage 26 Inner diameter portion 27 Spring chamber 28 Small hole 29 Spring 30 Plug 31 Step diameter portion 32 -Seal member 33 Spring receiver 35 Outer periphery 36 Large diameter portion 37 Seal member 38 Adjustment piston 39 Seal member 40 Adjustment chamber 42 Space chamber 44 Screw 45 Clearance 51 Annular groove 52 Annular chamber 53, 54 Support member 55 -Member 56 engaging portion 57 adjusting chamber 58 space chamber 60, 61 clearance 65 enlarged diameter portion 66 inner diameter portion 68 engaging portion 70 adjusting chamber 71 space chamber 73, 74 clearance e annular clearance F spring force P1 primary passage Pressure S1 receiving area S2 receiving area of the pressure P2 spring chamber of the pressure P3 pressure P4 secondary side passage of the adjustment chamber

Claims

A casing, a primary passage and a secondary passage formed in the casing, a sheet member fitted to a small-diameter portion provided in the casing so as to partition the primary passage and the secondary passage, and screwed into the casing Plug, one end engaged with the sheet member and the other end engaged with the plug, a poppet supported by the holding member and slidably fitted, a small diameter portion formed on the poppet, and an engagement with the small diameter portion A spring receiver that is inserted into a step diameter portion formed on the plug, a spring chamber that is formed by the step diameter portion and the holding member, a spring that is fitted to the spring receiver in the spring chamber, and a poppet A communication passage that communicates the spring chamber with the primary passage through an annular gap provided between the small diameter portion and the spring receiver, an adjustment piston that is slidably fitted to the outer periphery of the holding member, and an adjustment piston A space that is divided into one side and communicates with the secondary passage An adjustment chamber that communicates with the spring chamber defined on the other side of the adjustment piston, and the adjustment piston moves toward the space chamber to expand the volume of the spring chamber, thereby generating a differential pressure generated before and after the poppet. And a throttle passage formed of an annular gap formed by a spring receiver fitted to a small diameter portion of the poppet valve in the communication process of communicating the primary side passage and the spring chamber. A pressure increasing buffering mechanism for a relief valve, characterized in that:

A casing, a primary passage and a secondary passage formed in the casing, a sheet member fitted to a small-diameter portion provided in the casing so as to partition the primary passage and the secondary passage, and screwed into the casing Plug, one end engaged with the sheet member and the other end engaged with the plug, a poppet supported by the holding member and slidably fitted, a small diameter portion formed on the poppet, and an engagement with the small diameter portion A spring receiver that is inserted into a step diameter portion formed on the plug, a spring chamber that is formed by the step diameter portion and the holding member, a spring that is fitted to the spring receiver in the spring chamber, and a poppet A communication passage that connects the spring chamber and the primary side passage via an annular gap provided between the small diameter portion and the spring receiver, an annular groove formed in the inner diameter portion of the tip of the plug, and the annular groove And a support portion that is inserted into a chamber formed by the outer periphery of the holding member And a seal member, a space chamber defined by one support member and communicated with the secondary passage, and an adjustment chamber defined by the other support member and communicated with the spring chamber, and the support member moves to the space chamber side. In this way, the volume of the spring chamber is enlarged so that the opening of the seat portion is controlled by the differential pressure generated before and after the poppet, and the poppet valve is connected to the communication passage communicating the primary side passage and the spring chamber. A pressure increasing mechanism for a relief valve, characterized in that a throttle passage made of an annular gap formed by a small diameter portion and a spring receiver fitted therein is formed.

The annular groove is formed in the enlarged diameter portion of the holding member, and a support member and a seal member are inserted into a chamber formed by the annular groove and the inner diameter portion of the casing, and one support 3. The relief according to claim 2, wherein the space chamber defined by the member communicates with the secondary passage and the adjustment chamber defined by the other support member communicates with the spring chamber. Valve pressure boosting mechanism.