JP2004210164A

JP2004210164A - Hydraulic master cylinder for vehicle

Info

Publication number: JP2004210164A
Application number: JP2003000697A
Authority: JP
Inventors: Hidemitsu Haruhara; 日出光春原; Akihiro Mutsukawa; 明浩六川
Original assignee: Nissin Kogyo Co Ltd
Current assignee: Nissin Kogyo Co Ltd
Priority date: 2003-01-06
Filing date: 2003-01-06
Publication date: 2004-07-29
Anticipated expiration: 2023-01-06
Also published as: JP3919668B2

Abstract

<P>PROBLEM TO BE SOLVED: To improve durability of a seal ring disposed in a lid member, to reduce screwing amount of the lid member into the cylinder body, to shorten cylinder body, and to prevent fall of the lid member from the cylinder body and collection of sludge and dust in the lid member. <P>SOLUTION: The lid member 12 is formed of a sleeve 10 and a plug 11. Two circumferential grooves 10c are formed in the outer periphery of the sleeve 10, an O-ring 19 having the same diameter for liquid-tightly sealing the cylinder body 2 and the sleeve 10 is engaged with each circumferential groove 10c, and an output port 10d of working fluid is disposed between the circumferential grooves 10c. The sleeve 10 is inserted from one end opening of the cylinder body 2 while the opening side of the sleeve 10 is inserted toward the inside of the cylinder body, a second hydraulic chamber 18 is partitioned between a secondary piston 16 and the sleeve 10, and the plug 11 is screwed to one end of the cylinder body 2. A cover member 28c formed integrally with a reservoir 28 is mounted to one end of the cylinder body 2. When the lid member is mounted to the cylinder body, twisting of the seal ring is prevented, and the durability of the seal ring can be improved. While the lid member is certainly mounted to the cylinder body, the screwing amount into the cylinder body is reduced, and the cylinder body can be also reduced. <P>COPYRIGHT: (C)2004,JPO&NCIPI

Description

【０００１】
【発明の属する技術分野】
本発明は、自動車や自動二・三輪車等のブレーキやクラッチを液圧で作動させる車両用液圧マスタシリンダに係り、詳しくは、両端が開口したシリンダ本体の一端開口部を、蓋部材で閉塞してシリンダ孔を形成する液圧マスタシリンダの構造に関する。
【０００２】
【従来の技術】
従来、車両用液圧マスタシリンダには、両端が開口したシリンダ本体の一端開口部に、蓋部材を装着してシリンダ孔を形成したものがある。例えば、プランジャ型の液圧マスタシリンダでは、シリンダ本体の一端開口部に蓋部材が取り付けられるとともに、シリンダ本体内部にはピストンガイドが装着され、これらの内部にシリンダ孔が形成される。該シリンダ孔には、プライマリピストンとセカンダリピストンとが挿入され、これら２つのピストンの間に第１液圧室が、セカンダリピストンと蓋部材との間に第２液圧室がそれぞれ画成されている。
【０００３】
蓋部材は、シリンダ本体内に挿入される筒状部とシリンダ本体の一端部を覆うフランジ部とを一体に形成したもので、筒状部の外周先端側とシリンダ本体の内周にはそれぞれねじ部が設けられ、該ねじ部の後方に、シリンダ本体の吐出ポートに連通する出力ポートが形成されている。筒状部の先端とフランジ部近傍とにはシールリングが嵌着され、筒状部の先端側をシリンダ本体にねじ込むことにより、蓋部材がシリンダ本体に装着される（例えば、特許文献１参照）。
【０００４】
【特許文献１】
実公平８−２００２号公報（第１−２頁第１図）
【０００５】
【発明が解決しようとする課題】
しかし、上述のものでは、蓋部材をシリンダ本体に装着する際に、シールリングも蓋部材とともに回転しながらシリンダ本体にねじ込まれるため、シールリングが捩れて耐久性が低下する虞があった。
【０００６】
また、第２液圧室に液圧が発生したときに、シリンダ孔と螺合していない蓋部材のフランジ部側と、シリンダ孔との隙間に滲み出た作動液によって、フランジ部近傍に設けられたシールリングが液圧を受ける。このため、筒状部の先端側のシリンダ孔へのねじ込み量を充分に取り、蓋部材がシリンダ孔より脱落しないようにする必要があった。
【０００７】
さらに、蓋部材シリンダ孔に着脱させる際に、工具を入れる工具孔が蓋部材の底壁に形成されるが、この工具孔に埃や泥が詰まり、メンテナンスの際に工具が工具孔に挿入できないことがあった。
【０００８】
そこで本発明は、蓋部材をシリンダ本体に装着する際に、シールリングが捩れることを防止し、シールリングの耐久性を向上させるとともに、蓋部材を確実にシリンダ本体に装着させながらも、蓋部材のシリンダ本体へのねじ込み量を短くしてシリンダ本体を短く形成することができ、さらに、蓋部材が緩むことがあっても、シリンダ本体から脱落すること及び、蓋部材に泥や埃が溜まることを防止できる車両用液圧マスタシリンダを提供することを目的としている。
【０００９】
【課題を解決するための手段】
上記の目的を達成するため本発明は、両端が開口したシリンダ本体の一端開口部に、シールリングを介して蓋部材を装着して有底のシリンダ孔を形成し、該シリンダ孔にピストンを内挿し、該ピストンと蓋部材との間に液圧室を画成した車両用液圧マスタシリンダにおいて、前記蓋部材を、前記シリンダ本体に内挿される有底円筒状のスリーブと、外周にねじ部を備えたプラグとで構成し、前記スリーブに、シリンダ本体に設けた吐出ポートに連通する作動液の出力ポートを設け、該出力ポートの周囲を液密にシールする複数のシールリングを、前記シリンダ孔の周壁と前記スリーブとの間に前記出力ポートを挟んで配設し、前記スリーブを、開口側をシリンダ本体内部に向けてシリンダ本体に内挿するとともに、前記プラグを前記一端開口部に螺着して、前記スリーブを抜け止めしたことを特徴としている。
【００１０】
また、前記複数のシールリングは同径のＯリングを用いることができ、さらに、前記シリンダ本体の一端部に、前記プラグを覆うカバー部材を取り付けてもよく、この場合、前記カバー部材を、シリンダ本体に取り付けられた作動液を貯留するリザーバと一体に形成してもよい。
【００１１】
【発明の実施の形態】
以下、本発明の一形態例を図面に基づいて説明する。図１はプランジャ型の車両用液圧マスタシリンダを示す断面図で、マスタシリンダ１のシリンダ本体２は、両端が開口した円筒状に形成され、前方に形成される先端小径部２ａと、該先端小径部２ａよりやや大径の小径孔２ｂと、シリンダ本体後方に形成される中径孔２ｃと大径孔２ｄとを備えている。先端小径部２ａには、係合溝に第１カップシール３が嵌着され、小径孔２ｂにはシール支持体４に支持される第２カップシール５と、第１ピストンガイド６とが装着される。小径孔２ｂと中径孔２ｃとの間にはシール支持部材７が装着され、該シール支持部材７の両側に、第３カップシール８と第４カップシール９とが支持され、中径孔２ｃと大径孔２ｄとには、スリーブ１０とプラグ１１とで構成される蓋部材１２が装着される。スリーブ１０の内部には第２ピストンガイド１３が装着され、前記先端小径部２ａ，シール支持体４，第１ピストンガイド６，シール支持部材７，第２ピストンガイド１３及びスリーブ１０の底壁１０ａとによって、シリンダ孔１４が形成される。
【００１２】
シリンダ孔１４の内部には、プライマリピストン１５とセカンダリピストン１６とが挿入され、これらピストン１５，１６の間に第１液圧室１７が、また、セカンダリピストン１６とスリーブ１０との間に第２液圧室１８がそれぞれ画成される。
【００１３】
スリーブ１０は周壁１０ｂと底壁１０ａとを有した有底円筒状に形成され、周壁１０ｂの開口側と底壁側とに、周溝１０ｃ，１０ｃが形成され、この周溝１０ｃ，１０ｃに同径のＯリング１９，１９（本発明のシールリング）が嵌着されている。また、周溝１０ｃ，１０ｃ間の周壁１０ｂには、シリンダ本体２の中径孔２ｃに穿設された吐出ポートＰに連通する出力ポート１０ｄが穿設され、該出力ポート１０ｄを介して吐出ポートＰより、図示しない車輪のブレーキ装置へ作動液が供給される。
【００１４】
プラグ１１は外周に雄ねじ部１１ａを有した円筒体で、中央部には、工具を挿入する六角孔１１ｂが穿設されている。スリーブ１０に内挿される第２ピストンガイド１３は、円筒状に形成され、第４カップシール９のリップ内に突出するカップ抑えと、第２液圧室１８と出力ポート１０ｄを繋ぐ液通路を形成するための溝部１３ａとを備えている。
【００１５】
スリーブ１０は開口側をシリンダ本体内部に向けて、シリンダ本体２の大径孔２ｄ（本発明の一端開口部）より中径孔２ｃに向けて挿入され、Ｏリング１９，１９によって中径孔２ｃとスリーブ１０とが液密にシールされる。前記大径孔２ｄにはめねじが形成されており、スリーブ１０をシリンダ本体２に挿入後、プラグ１１の雄ねじ部１１ａを大径孔２ｄのめねじに、プラグ１１の端面がスリーブ１０の底壁１０ａに当接するまでねじ込むことによって、スリーブ１０がプラグ１１によって抜け止めされる。
【００１６】
シリンダ孔１４の先端側には、前記プライマリピストン１５が、後端側には前記セカンダリピストン１６がそれぞれ配設される。プライマリピストン１５は、先端側にプッシュロッド２０の収容孔１５ａが、また、後端側に大径凹部１５ｂが形成され、シリンダ本体２の先端部に取り付けたブーツ２１及び第１カップシール３，第２カップシール５によって、シリンダ孔１４内に液密に収容される。また、大径凹部１５ｂを内部に備えたプライマリピストン１５の後端側周壁には、複数の通孔１５ｃが穿設され、大径凹部１５ｂの内部には、プライマリピストン１５とセカンダリピストン１６とを繋ぐガイドピン２２のリテーナ２３が収容される。リテーナ２３はガイドピン２２を収容できる長さを有したコップ状に形成され、その周壁には、リテーナ内外を連通させる複数の通孔２３ａが穿設されている。
【００１７】
セカンダリピストン１６は、後端側に大径凹部１６ａ，先端側に中径凹部１６ｂがそれぞれ形成され、第３カップシール８及び第４カップシール９を介して、シリンダ孔１４に液密に収容され、大径凹部１６ａには、前記ガイドピン２２の先端頭部を固定したリテーナ２４が取り付けられる。プライマリピストン１５の大径凹部１５ｂとセカンダリピストン１６の大径凹部１６ａとの間には前記第１液圧室１７が画成され、前記リテーナ２３，２４間に、第１リターンスプリング２５が縮設されている。中径凹部１６ｂを内部に備えたセカンダリピストン１６の後端側周壁には複数の通孔１６ｃが穿設され、中径凹部１６ｂと前記スリーブ１０の底壁１０ａとの間には前記第２液圧室が画成され、中径凹部１６ｂと前記スリーブ１０の底壁１０ａ間に、第２リターンスプリング２６が縮設される。
【００１８】
シリンダ本体２の上部には一対のボス部２ｅ，２ｆが突設され、該ボス部２ｅ，２ｆにはグロメットシール２７，２７を介してリザーバ２８が設けられる。シリンダ本体２の前部側周壁には、シリンダ本体前部側に形成されたボス部２ｅの底壁と連通する液通孔２ｇが穿設され、前記シール支持体４には、液通孔２ｇとシリンダ孔１４内とに連通する連通孔４ａが穿設され、第１液圧室１７は、プライマリピストン１５に形成した通孔１５ｃと、前記連通孔４ａ及び前記液通孔２ｇとを介して、リザーバ２８と連通している。また、シリンダ本体２の後部側周壁には、シリンダ本体後部側に形成されたボス部２ｆの底壁と連通する液通孔２ｈが穿設され、前記シール支持部材７には、液通孔２ｈとシリンダ孔１４内とに連通する連通孔７ａが穿設され、第２液圧室１８は、セカンダリピストン１６に形成した通孔１６ｃと、前記連通孔７ａ及び前記液通孔２ｈとを介してリザーバ２８と連通している。
【００１９】
リザーバ２８は、樹脂で形成されるもので、作動液の貯液室を内部に備えたリザーバ本体２８ａと、該リザーバ本体２８ａの上部開口を覆うキャップ２８ｂとを備えている。リザーバ本体２８ａには、シリンダ本体２の前記プラグ１１を螺着した後端側に着脱可能に被着されるカバー部材２８ｃと、該カバー部材２８ｃとシリンダ本体２とを繋ぐ連結部２８ｄとが一体に形成されている。
【００２０】
プライマリピストン１５とセカンダリピストン１６とは、非作動時には、リターンスプリング２５，２６の弾発力によって、図１に示される位置に配設され、第１液圧室１７及び第２液圧室１８は、リザーバ２８とそれぞれ連通している。作動時にプッシュロッドがプライマリピストン１５を押動すると、プライマリピストン１５が第１液圧室１７内の第１リターンスプリング２５を圧縮しながらシリンダ孔１４を底部方向へ前進し、これと同時にセカンダリピストン１６が第２リターンスプリング２６を圧縮しながらシリンダ孔底部方向への前進を開始する。セカンダリピストン１６の通孔１６ｃが第４カップシール９に塞がれると、第２液圧室１８とリザーバ２８との連通が遮断されることにより、第２液圧室１８に液圧を発生させる。昇圧された作動液は、スリーブ１０の底部１０ａ側より、液通孔２０を通り、スリーブ１０の出力ポート１０ｄ及びシリンダ本体２の吐出ポートＰを介して、他方のブレーキ系統に供給される。
【００２１】
この前進に伴って、リターンスプリング２６のセット荷重と第２液圧室１８の圧力が、リターンスプリング２５をうわまわると、第１液圧室１７が圧縮されて第１液圧室１７に液圧を発生させ、この発生液圧が一方のブレーキ系統に供給される。また、制動を解除すると、プライマリピストン１５とセカンダリピストン１６とは各リターンスプリング２５，２６により初期の位置に復帰する。
【００２２】
本形態例のマスタシリンダ１では、スリーブ１０とプラグ１１とで蓋部材１２を形成し、Ｏリング１９，１９を備えたスリーブ１０をシリンダ本体２に挿入し、その後プラグ１１をシリンダ本体２に螺着するので、蓋部材装着時に、Ｏリング１９，１９が捩れて損傷することを防止できる。
【００２３】
また、第２液圧室１８に液圧が発生した際に、スリーブ１０に穿設された出力ポート１０ｄより滲み出た作動液によって、スリーブ１０の先端側と底部側とに配設された同径のＯリング１９，１９に、略等しく液圧が係るため、スリーブ１０の底壁方向に係る力を小さくすることができる。このため、プラグ１１の雄ねじ部１１ａの長さを短くすることができ、シリンダ本体２の全長を短く抑えることができる。
【００２４】
さらに、プラグ１１の外側を前記カバー部材２８ｃが覆っていることにより、プラグ１１が緩むことがあってもシリンダ本体２から脱落する虞がない。また、カバー部材２８ｃによって、プラグ１１外壁に形成した六角孔１１ｂに泥や埃が溜まることを防止でき、メンテナンスの際には、カバー部材２８ｃをシリンダ本体２から外し、工具を六角孔１１ｂに挿入してプラグ１１を簡単に着脱することができる。さらに、カバー部材２８ｃはリザーバ本体２８ａと一体に形成されているので、部品点数を増やすことなく安価に提供できるとともに、メンテナンスの際に紛失する虞がない。
【００２５】
尚、本発明は、上述の形態例のように、タンデムタイプのプランジャ型マスタシリンダに適用されるものに限らず、シングルタイプのプランジャ型マスタシリンダにも適用でき、さらに、プランジャ型以外のどのようなタイプのマスタシリンダにも適用できる。
【００２６】
また、本発明のシールリングは上述の形態例のようにＯリングに限るものではなく、他の形態のシールリングでも差し支えなく、さらに、シールリングを嵌着する周溝は、スリーブに形成するものに限らず、シリンダ孔周壁に設けても良い。また、プラグを覆うカバー部材は、リザーバ本体と別体に形成するものでも良い。
【００２７】
【発明の効果】
以上説明したように、本発明によれば、蓋部材をシリンダ本体に装着する際に、シールリングが捩れることを防止し、シールリングの耐久性を向上させることができる。また、蓋部材を確実にシリンダ本体に装着させながらも、シリンダ本体へのねじ込み量を短くし、シリンダ本体を短く形成することができる。さらに、蓋部材が緩むことがあっても、シリンダ本体から脱落するすることを防止するとともに、蓋部材に泥や埃が溜まることを防止し、メンテナンスの際に効率よく蓋部材を着脱できる。
【図面の簡単な説明】
【図１】本発明の一形態例を示すプランジャ型のマスタシリンダの断面図
【図２】本発明の一形態例を示す要部拡大断面図
【図３】図２のＩＩＩ−ＩＩＩ断面図
【符号の説明】
１…マスタシリンダ、２…シリンダ本体、２ａ…先端小径部、２ｂ…小径孔、２ｃ…中径孔、２ｄ…大径孔、１０…スリーブ、１０ａ…底壁、１０ｃ…周壁、１０ｄ…出力ポート、１１…プラグ、１１ａ…雄ねじ部、１２…蓋部材、１４…シリンダ孔、１５…プライマリピストン、１６…セカンダリピストン、１７…第１液圧室、１８…第２液圧室、１９…Ｏリング、２５…第１リターンスプリング、２６…第２リターンスプリング、２８…リザーバ、２８ｃ…カバー部材、Ｐ…吐出ポート[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a vehicle hydraulic master cylinder that hydraulically operates brakes and clutches of automobiles, motorcycles, three-wheeled vehicles, and the like, and more specifically, closes an opening at one end of a cylinder body having both ends opened with a lid member. The present invention relates to a structure of a hydraulic master cylinder in which a cylinder hole is formed.
[0002]
[Prior art]
2. Description of the Related Art Conventionally, there is a vehicular hydraulic master cylinder in which a cylinder member is formed by attaching a lid member to one end opening of a cylinder body having both ends opened. For example, in a plunger type hydraulic master cylinder, a lid member is attached to one end opening of the cylinder body, a piston guide is mounted inside the cylinder body, and a cylinder hole is formed inside these. A primary piston and a secondary piston are inserted into the cylinder hole, and a first hydraulic chamber is defined between the two pistons, and a second hydraulic chamber is defined between the secondary piston and the lid member. I have.
[0003]
The lid member is formed by integrally forming a cylindrical portion inserted into the cylinder main body and a flange portion covering one end of the cylinder main body. And an output port communicating with the discharge port of the cylinder body is formed behind the screw portion. A seal ring is fitted to the distal end of the cylindrical portion and the vicinity of the flange portion, and the distal end side of the cylindrical portion is screwed into the cylinder body, whereby the lid member is attached to the cylinder body (for example, see Patent Document 1). .
[0004]
[Patent Document 1]
Japanese Utility Model Publication No. 8-2002 (page 1-2, FIG. 1)
[0005]
[Problems to be solved by the invention]
However, in the above-described configuration, when the cover member is mounted on the cylinder body, the seal ring is also screwed into the cylinder body while rotating together with the cover member, so that the seal ring may be twisted and durability may be reduced.
[0006]
Also, when hydraulic pressure is generated in the second hydraulic chamber, the hydraulic fluid oozes into the gap between the cylinder hole and the flange side of the lid member that is not screwed with the cylinder hole, and is provided near the flange portion. The sealed ring receives hydraulic pressure. For this reason, it is necessary to take a sufficient amount of screwing into the cylinder hole on the tip end side of the cylindrical portion so that the lid member does not fall out of the cylinder hole.
[0007]
Further, a tool hole for inserting a tool is formed in the bottom wall of the cover member when the tool is to be attached to or detached from the cover member cylinder hole. There was something.
[0008]
Therefore, the present invention prevents the seal ring from being twisted when the cover member is mounted on the cylinder body, improves the durability of the seal ring, and ensures that the cover member is securely mounted on the cylinder body. The amount of screwing of the member into the cylinder body can be shortened to shorten the cylinder body. Further, even if the lid member is loosened, the member may fall off from the cylinder body, and mud or dust may accumulate on the lid member. It is an object of the present invention to provide a hydraulic master cylinder for a vehicle that can prevent the occurrence of such a problem.
[0009]
[Means for Solving the Problems]
In order to achieve the above object, the present invention provides a cylinder body having a bottom by mounting a lid member through a seal ring at an opening of one end of a cylinder body having both ends opened, and a piston inside the cylinder hole. A hydraulic master cylinder for a vehicle having a hydraulic chamber inserted between the piston and the lid member, wherein the lid member has a bottomed cylindrical sleeve inserted into the cylinder body, and a threaded portion formed on the outer periphery. A plurality of seal rings, which are provided with an output port for the hydraulic fluid that communicates with a discharge port provided in the cylinder body, and seal the periphery of the output port in a liquid-tight manner. The output port is disposed between the peripheral wall of the hole and the sleeve, the sleeve is inserted into the cylinder body with the opening side facing the inside of the cylinder body, and the plug is opened at the one end. And screwed to, it is characterized in that it has retained the sleeve.
[0010]
In addition, the plurality of seal rings may use O-rings having the same diameter, and a cover member that covers the plug may be attached to one end of the cylinder body. In this case, the cover member may be a cylinder. It may be formed integrally with a reservoir attached to the main body and storing the working fluid.
[0011]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, an embodiment of the present invention will be described with reference to the drawings. FIG. 1 is a cross-sectional view showing a plunger-type hydraulic master cylinder for a vehicle. A cylinder body 2 of the master cylinder 1 is formed in a cylindrical shape with both ends opened, and a small-diameter portion 2a formed forward and a small-diameter portion 2a formed forward. It has a small diameter hole 2b slightly larger in diameter than the small diameter portion 2a, a medium diameter hole 2c and a large diameter hole 2d formed at the rear of the cylinder body. The first cup seal 3 is fitted in the engagement groove at the tip small diameter portion 2a, and the second cup seal 5 supported by the seal support 4 and the first piston guide 6 are mounted in the small diameter hole 2b. You. A seal support member 7 is mounted between the small-diameter hole 2b and the medium-diameter hole 2c. On both sides of the seal support member 7, a third cup seal 8 and a fourth cup seal 9 are supported. The lid member 12 composed of the sleeve 10 and the plug 11 is attached to the large diameter hole 2d. A second piston guide 13 is mounted inside the sleeve 10, and the tip small diameter portion 2 a, the seal support 4, the first piston guide 6, the seal support member 7, the second piston guide 13, and the bottom wall 10 a of the sleeve 10 are provided. Thereby, the cylinder hole 14 is formed.
[0012]
A primary piston 15 and a secondary piston 16 are inserted into the cylinder hole 14, and a first hydraulic chamber 17 is provided between the pistons 15 and 16, and a second hydraulic chamber 17 is provided between the secondary piston 16 and the sleeve 10. Hydraulic chambers 18 are respectively defined.
[0013]
The sleeve 10 is formed in a bottomed cylindrical shape having a peripheral wall 10b and a bottom wall 10a, and peripheral grooves 10c, 10c are formed on the opening side and the bottom wall side of the peripheral wall 10b, and are formed in the peripheral grooves 10c, 10c. O-rings 19, 19 having the diameter (the seal ring of the present invention) are fitted. Further, an output port 10d communicating with a discharge port P formed in the medium diameter hole 2c of the cylinder body 2 is formed in the peripheral wall 10b between the circumferential grooves 10c, 10c, and the discharge port is formed through the output port 10d. The hydraulic fluid is supplied from P to a brake device for a wheel (not shown).
[0014]
The plug 11 is a cylindrical body having a male screw portion 11a on the outer periphery, and a hexagonal hole 11b for inserting a tool is formed in the center portion. The second piston guide 13 inserted into the sleeve 10 is formed in a cylindrical shape, and suppresses the cup protruding into the lip of the fourth cup seal 9 and forms a liquid passage connecting the second hydraulic pressure chamber 18 and the output port 10d. And a groove 13a for performing the operation.
[0015]
The sleeve 10 is inserted from the large diameter hole 2d (one end opening of the present invention) of the cylinder body 2 toward the medium diameter hole 2c with the opening side facing the inside of the cylinder body. And the sleeve 10 are sealed in a liquid-tight manner. An internal thread is formed in the large-diameter hole 2d. After the sleeve 10 is inserted into the cylinder body 2, the external thread portion 11a of the plug 11 is changed to an internal thread of the large-diameter hole 2d. The sleeve 10 is prevented from coming off by the plug 11 by screwing it until it comes into contact with 10a.
[0016]
The primary piston 15 is disposed on the front end side of the cylinder hole 14, and the secondary piston 16 is disposed on the rear end side. The primary piston 15 has a receiving hole 15a for the push rod 20 formed on the distal end side and a large-diameter concave portion 15b formed on the rear end side, and the boot 21 and the first cup seal 3 attached to the distal end of the cylinder body 2 have the same shape. The two-cup seal 5 accommodates the cylinder hole 14 in a liquid-tight manner. A plurality of through holes 15c are formed in a rear end side peripheral wall of the primary piston 15 having the large-diameter recess 15b therein, and the primary piston 15 and the secondary piston 16 are provided inside the large-diameter recess 15b. The retainer 23 of the connecting guide pin 22 is housed. The retainer 23 is formed in a cup shape having a length capable of accommodating the guide pin 22, and a plurality of through holes 23 a communicating the inside and outside of the retainer are formed in a peripheral wall thereof.
[0017]
The secondary piston 16 has a large-diameter concave portion 16a formed on the rear end side and a medium-diameter concave portion 16b formed on the distal end side, and is housed in the cylinder hole 14 in a liquid-tight manner via the third cup seal 8 and the fourth cup seal 9. A retainer 24 to which the head of the guide pin 22 is fixed is attached to the large-diameter recess 16a. The first hydraulic chamber 17 is defined between the large-diameter recess 15b of the primary piston 15 and the large-diameter recess 16a of the secondary piston 16, and a first return spring 25 is contracted between the retainers 23 and 24. Have been. A plurality of through-holes 16c are formed in the peripheral wall on the rear end side of the secondary piston 16 having the medium-diameter recess 16b therein, and the second liquid is provided between the middle-diameter recess 16b and the bottom wall 10a of the sleeve 10. A pressure chamber is defined, and a second return spring 26 is contracted between the middle recess 16 b and the bottom wall 10 a of the sleeve 10.
[0018]
A pair of bosses 2e, 2f are provided at the upper part of the cylinder body 2 to project therefrom, and the bosses 2e, 2f are provided with reservoirs 28 via grommet seals 27, 27. A liquid through-hole 2g communicating with a bottom wall of a boss 2e formed on the front side of the cylinder main body is formed in a front side peripheral wall of the cylinder body 2, and a liquid through-hole 2g is formed in the seal support 4. A communication hole 4a communicating with the inside of the cylinder hole 14 is formed, and the first hydraulic chamber 17 is formed through a communication hole 15c formed in the primary piston 15 and the communication hole 4a and the liquid communication hole 2g. , Reservoir 28. A liquid through hole 2h communicating with a bottom wall of a boss 2f formed on the rear side of the cylinder body 2 is formed in a rear peripheral wall of the cylinder body 2, and a liquid through hole 2h is formed in the seal support member 7. A communication hole 7a that communicates with the inside of the cylinder hole 14 is formed. The second hydraulic chamber 18 communicates with the second piston 16 via a communication hole 16c formed in the secondary piston 16 and the communication hole 7a and the liquid communication hole 2h. It communicates with the reservoir 28.
[0019]
The reservoir 28 is formed of resin, and includes a reservoir main body 28a having a reservoir for the working fluid therein, and a cap 28b covering an upper opening of the reservoir main body 28a. The reservoir body 28a is integrally formed with a cover member 28c detachably attached to the rear end side of the cylinder body 2 to which the plug 11 is screwed, and a connecting portion 28d connecting the cover member 28c and the cylinder body 2. Is formed.
[0020]
When the primary piston 15 and the secondary piston 16 are not operated, they are disposed at the positions shown in FIG. 1 by the resilient force of the return springs 25 and 26, and the first hydraulic chamber 17 and the second hydraulic chamber 18 , Reservoir 28 respectively. When the push rod pushes the primary piston 15 during operation, the primary piston 15 advances the cylinder hole 14 toward the bottom while compressing the first return spring 25 in the first hydraulic chamber 17, and at the same time, the secondary piston 16 Starts advancing toward the bottom of the cylinder hole while compressing the second return spring 26. When the through hole 16 c of the secondary piston 16 is closed by the fourth cup seal 9, the communication between the second hydraulic chamber 18 and the reservoir 28 is cut off, so that a hydraulic pressure is generated in the second hydraulic chamber 18. . The pressurized hydraulic fluid is supplied to the other brake system from the bottom 10 a side of the sleeve 10 through the liquid through hole 20, via the output port 10 d of the sleeve 10 and the discharge port P of the cylinder body 2.
[0021]
When the set load of the return spring 26 and the pressure of the second hydraulic chamber 18 exceed the return spring 25 with this advance, the first hydraulic chamber 17 is compressed and hydraulic pressure is applied to the first hydraulic chamber 17. Is generated, and the generated hydraulic pressure is supplied to one of the brake systems. When the braking is released, the primary piston 15 and the secondary piston 16 return to their initial positions by the respective return springs 25, 26.
[0022]
In the master cylinder 1 of the present embodiment, the cover member 12 is formed by the sleeve 10 and the plug 11, the sleeve 10 having the O-rings 19, 19 is inserted into the cylinder body 2, and then the plug 11 is screwed into the cylinder body 2. The O-rings 19, 19 can be prevented from being twisted and damaged when the lid member is attached.
[0023]
Further, when a hydraulic pressure is generated in the second hydraulic chamber 18, the hydraulic fluid oozed from an output port 10 d formed in the sleeve 10 is provided on the distal end side and the bottom side of the sleeve 10 by the hydraulic fluid. Since the hydraulic pressure is applied substantially equally to the O-rings 19 and 19 having the diameter, the force in the bottom wall direction of the sleeve 10 can be reduced. For this reason, the length of the male screw portion 11a of the plug 11 can be reduced, and the overall length of the cylinder body 2 can be reduced.
[0024]
Further, since the outside of the plug 11 is covered by the cover member 28c, even if the plug 11 is loosened, there is no risk of falling off from the cylinder body 2. Further, the cover member 28c can prevent mud and dust from collecting in the hexagonal hole 11b formed on the outer wall of the plug 11, and during maintenance, remove the cover member 28c from the cylinder body 2 and insert a tool into the hexagonal hole 11b. Thus, the plug 11 can be easily attached and detached. Further, since the cover member 28c is formed integrally with the reservoir main body 28a, it can be provided at a low cost without increasing the number of parts, and there is no risk of loss during maintenance.
[0025]
Incidentally, the present invention is not limited to the one applied to the tandem type plunger type master cylinder as in the above-described embodiment, but can also be applied to a single type plunger type master cylinder. Applicable to various types of master cylinders.
[0026]
In addition, the seal ring of the present invention is not limited to the O-ring as in the above-described embodiment, and any other form of seal ring may be used. Further, the peripheral groove for fitting the seal ring is formed in the sleeve. The present invention is not limited to this, and may be provided on the peripheral wall of the cylinder hole. Further, the cover member that covers the plug may be formed separately from the reservoir body.
[0027]
【The invention's effect】
As described above, according to the present invention, when the lid member is mounted on the cylinder body, the seal ring can be prevented from being twisted, and the durability of the seal ring can be improved. Further, while the lid member is securely attached to the cylinder body, the amount of screwing into the cylinder body can be reduced, and the cylinder body can be made shorter. Furthermore, even if the lid member is loosened, the lid member is prevented from falling off from the cylinder body, and the lid member is prevented from collecting mud and dust, so that the lid member can be efficiently attached and detached during maintenance.
[Brief description of the drawings]
FIG. 1 is a cross-sectional view of a plunger-type master cylinder showing an embodiment of the present invention. FIG. 2 is an enlarged cross-sectional view of a main part showing an embodiment of the present invention. FIG. Explanation of reference numerals]
DESCRIPTION OF SYMBOLS 1 ... Master cylinder, 2 ... Cylinder main body, 2a ... Tip small diameter part, 2b ... Small diameter hole, 2c ... Medium diameter hole, 2d ... Large diameter hole, 10 ... Sleeve, 10a ... Bottom wall, 10c ... Peripheral wall, 10d ... Output port , 11 plug, 11a male screw part, 12 lid member, 14 cylinder hole, 15 primary piston, 16 secondary piston, 17 first hydraulic chamber, 18 second hydraulic chamber, 19 O-ring , 25 ... first return spring, 26 ... second return spring, 28 ... reservoir, 28c ... cover member, P ... discharge port

Claims

At one end opening of the cylinder body with both ends opened, a lid member is attached via a seal ring to form a bottomed cylinder hole, a piston is inserted into the cylinder hole, and between the piston and the lid member. In a vehicle hydraulic master cylinder defining a hydraulic chamber, the lid member is constituted by a bottomed cylindrical sleeve inserted into the cylinder body, and a plug having a threaded portion on the outer periphery, wherein the sleeve A hydraulic fluid output port communicating with a discharge port provided in the cylinder body, and a plurality of seal rings for sealing the periphery of the output port in a liquid-tight manner between the peripheral wall of the cylinder hole and the sleeve. The output port is interposed, the sleeve is inserted into the cylinder body with the opening side facing the inside of the cylinder body, and the plug is screwed into the one end opening to prevent the sleeve from coming off. Vehicle hydraulic master cylinder, characterized in that the.

2. The hydraulic master cylinder for a vehicle according to claim 1, wherein the plurality of seal rings are O-rings having the same diameter.

3. The hydraulic master cylinder for a vehicle according to claim 1, wherein a cover member that covers the plug is attached to one end of the cylinder body.

4. The hydraulic master cylinder for a vehicle according to claim 3, wherein the cover member is formed integrally with a reservoir attached to the cylinder body for storing the hydraulic fluid.