JPH02309030A - Oil-hydraulic damper - Google Patents

Abstract

PURPOSE:To stabilize the performance of an oil damper and decrease the number of parts used to a buffer valve by allowing a valve piece to protrude from a boss fixed to a partitioning member, wherein the valve piece deflects to the low pressure side when a pressure difference is generated between two oil pressure chambers, and partitioning a throttle between a ring consolidated with the boss through a coupling piece and the movable end of the valve piece. CONSTITUTION:A piston 5 is provided with a flow path 16 formed from a through hole 20 which is for communication between two oil chambers 6, 7, and in the hollow 21 of this piston 5, an upper spacer cylinder 22, upper fulcrum plate 25, valve plate 26, lower fulcrum plate 25, and lower spacer cylinder 23 are accommodated and secured to a piston rod by a nut 27. A ridge 28 is formed, which faces the outside circumferential end of the valve plate 26 and partitions a throttle 16a, and a ring 32 formed in a single piece with the valve plate 26 is pinched between No.1, 2 crests 29, 30 of this ridge. Accordingly the damping forces both for contraction and elongation can be generated by a single buffer valve 9, which enables decrease in the number of parts, suppression of the cost, and obtainment of stabilized damping performance.

Description

【発明の詳細な説明】 Ａ０発明の目的 （１）　　産業上の利用分野 本発明は、自動車の懸架装置等に取付けられてその作動
に減衰力を与える油圧緩衝器に関し、特に、少なくとも
二つの油室と、この両油室間を連通ずる流路を有して両
油室間を仕切る仕切部材と、前記流路に生じる油の流れ
を制御すべく前記仕切部材に設けられた緩衝弁とを備え
た油圧緩衝器の改良に関する。Detailed Description of the Invention A0 Object of the Invention (1) Industrial Application Field The present invention relates to a hydraulic shock absorber that is attached to a suspension system of an automobile and provides damping force to its operation, and in particular, A partition member having a flow path communicating between the two oil chambers and partitioning the two oil chambers, and a buffer valve provided on the partition member to control the flow of oil generated in the flow path. This invention relates to improvements in hydraulic shock absorbers.

（２）従来の技術 この種緩衝器は、例えば特開昭５３−１１７１７１号公
報に開示されているように、既に知られている。(2) Prior Art This type of buffer is already known, as disclosed in, for example, Japanese Patent Application Laid-Open No. 53-117171.

（３）発明が解決しようとする課題 従来の油圧緩衝器では、緩衝弁として、緩衝器の収縮時
、即ち仕切部材としてのピストンの下降時、下部油室か
ら上部油室への油の流れを制御して収縮減衰力を発生す
る第１１１衝弁と、緩衝器の伸長時、即ちピストンの上
昇時、上部油室から下部油室への油の流れを制御して伸
長減衰力を発生する第２緩衝弁とを併設しているので、
緩衝弁の部品点数が多く、コスト高となる傾向がある上
、緩衝器の収縮及び伸長が高速で繰返される場合には、
それまで開いていた一方の緩衝弁が完全に閉じ位置まで
復帰しないうちに他方の緩衝弁が開くことがあり、この
ような現象は緩衝性能を損う原因となる。(3) Problems to be Solved by the Invention In conventional hydraulic shock absorbers, the buffer valve prevents the flow of oil from the lower oil chamber to the upper oil chamber when the shock absorber contracts, that is, when the piston as a partition member descends. a 111th valve that controls and generates a contraction damping force; and a 111th valve that controls oil flow from the upper oil chamber to the lower oil chamber to generate an expansion damping force when the shock absorber is extended, that is, when the piston is raised. Since it is equipped with 2 buffer valves,
Buffer valves have a large number of parts and tend to be expensive, and if the shock absorber contracts and expands repeatedly at high speed,
The other buffer valve may open before one of the previously open buffer valves has fully returned to its closed position, and this phenomenon causes loss of buffer performance.

本発明は、か−る事情に濡みてなされたもので、緩衝弁
の部品点数が少なく、しかも常に安定した緩衝性能を発
揮し得る油圧緩衝器を提供することを目的とする。The present invention was developed in response to the above circumstances, and an object of the present invention is to provide a hydraulic shock absorber which has a small number of shock absorbing valve parts and which can always exhibit stable shock absorbing performance.

Ｂ０発明の構成 （１）　　！ｌｉ！を解決するための手段上記目的を達
成するために、本発明は、前記緩衝弁を、仕切部材に固
着されるボス部と、このボス部から放射状に突出し、前
記両油室間の圧力差発生時に低圧側へ撓む複数の弁片と
、これら弁片を囲繞して仕切部材に固着され、これら弁
片の可動端との間に前記流路の絞り部を画成するリング
体と、前記弁片間に配置されて前記ボス部及びリング体
間を一体に連結する連結片とから構成したことを特徴と
する。Structure of B0 invention (1)! li! Means for Solving the Problems In order to achieve the above object, the present invention provides the buffer valve with a boss portion fixed to the partition member and radially protruding from the boss portion to create a pressure difference between the oil chambers. a plurality of valve pieces that sometimes bend toward the low pressure side; a ring body that surrounds these valve pieces and is fixed to a partition member and defines a constricted part of the flow path between the movable ends of these valve pieces; It is characterized by comprising a connecting piece disposed between the valve pieces and integrally connecting the boss part and the ring body.

（２）作　用 上記構成によれば、緩衝器の伸縮が繰返されると、両地
室の油が流路を経て両油室間を交互に往き来し、各弁片
は流路の絞り部を最小開度とする中立位置を必ず経由し
て一方向と他方向とへ交互に撓んで絞り部を適度に開き
、これにより減衰力を制御する。(2) Effect According to the above configuration, when the shock absorber is repeatedly expanded and contracted, the oil in both chambers alternately moves back and forth between both oil chambers via the flow path, and each valve piece is connected to the constricted portion of the flow path. The damping force is controlled by alternately bending in one direction and the other direction through a neutral position where the minimum opening is made, and opening the throttle part appropriately.

また、複数の弁片を支持するボス部とリング体とは連結
片を介して一体に連結されているので、弁片及びリング
体間の絞り部は、組立誤差の影響を受けることなく、常
に適正な寸法精度を保つことができる。In addition, since the boss part and the ring body that support the plurality of valve pieces are integrally connected via the connecting piece, the throttle part between the valve pieces and the ring body is always maintained without being affected by assembly errors. Appropriate dimensional accuracy can be maintained.

（３）実施例 以下、図面により本発明の一実施例について説明する。(3) Examples An embodiment of the present invention will be described below with reference to the drawings.

先ず第１図において、油圧緩衝器１は、外筒２と、この
外筒２内に収容されて同心上でそれに固着され、内部に
油を満たしたシリンダ３と、外筒２の上方へ突出するピ
ストンロッド４に連結されてシリンダ３に摺動自在に嵌
合する仕切部材としてのピストン５とを備える。ピスト
ン５はシリンダ３内を上下二つの油室６，７に区分し、
外筒２及びシリンダ３はそれらの間にオイルリザーバ８
を画成する。このリザーバ８の油面上空間には、空気も
しくは不活性ガスが所定圧力をもって封入される。First, in FIG. 1, the hydraulic shock absorber 1 includes an outer cylinder 2, a cylinder 3 housed in the outer cylinder 2 and fixed concentrically thereto, and filled with oil inside, and protruding upward from the outer cylinder 2. The piston 5 is connected to a piston rod 4 and is slidably fitted into the cylinder 3 as a partition member. The piston 5 divides the inside of the cylinder 3 into two upper and lower oil chambers 6 and 7.
The outer cylinder 2 and the cylinder 3 have an oil reservoir 8 between them.
Define. Air or an inert gas is sealed in the space above the oil surface of the reservoir 8 at a predetermined pressure.

ピストン５には、両地室６．７間を連通ずる流路１６と
、緩衝器１の収縮時、上記流路１６を通して行われる油
室６．７間の油の流通を制御して減衰力を発生する緩衝
弁９が設けられる。The piston 5 has a flow path 16 that communicates between the two chambers 6 and 7, and a damping force that controls the flow of oil between the oil chambers 6 and 7 through the flow path 16 when the shock absorber 1 is contracted. A buffer valve 9 is provided which generates a .

また、シリンダ３の下端と外筒２の底壁との間には、第
２の仕切部材１７が挟止され、この仕切部材１７には、
特に緩衝器１の中、高速伸縮時、下部油室７及びオイル
リザーバ８間での油の流通に抵抗を与えて減衰力を発生
するオリフィス１０が設けられる。Further, a second partition member 17 is sandwiched between the lower end of the cylinder 3 and the bottom wall of the outer cylinder 2, and this partition member 17 includes:
In particular, an orifice 10 is provided in the shock absorber 1 to provide resistance to the flow of oil between the lower oil chamber 7 and the oil reservoir 8 and to generate a damping force during high-speed expansion and contraction.

ピストンロッド４の上端には車体への取付けのための上
部取付部材１１が固着され、また外筒２の下端には車輪
支持腕への取付けのための下部取付部材１２が固着され
、上部取付部材１１の下面に形成された上部ばね座１３
と、外筒２の外周に固設された下部ばね座１４との間に
コイル状の懸架ばね１５が縮設される。An upper mounting member 11 is fixed to the upper end of the piston rod 4 for mounting to the vehicle body, and a lower mounting member 12 is fixed to the lower end of the outer cylinder 2 for mounting to the wheel support arm. Upper spring seat 13 formed on the lower surface of 11
A coiled suspension spring 15 is compressed between the lower spring seat 14 and the lower spring seat 14 fixed to the outer periphery of the outer cylinder 2.

前記流路１６及び緩衝弁９について第２図により説明す
る。The flow path 16 and the buffer valve 9 will be explained with reference to FIG.

ピストン５は、複数の通孔２０を有する端壁５ａを上向
きにしたカップ形をなしており、このピストン５の中空
部及び通孔２０により前記流路１６が構成される。The piston 5 has a cup shape with an end wall 5a facing upward and has a plurality of through holes 20, and the hollow portion of the piston 5 and the through holes 20 constitute the flow path 16.

ピストン５の中空部２１には上方から順に上部間隔筒２
２、円形の上部支点板２４、円形の弁板２６、円形の下
部支点板２５及び下部間隔１２３が収容され、これらは
ピストン５の端壁５ａと共にピストンロッド４の小径端
部４ａに中心部を貫通され、そしてこの小径端部４ａに
螺合されるナツト２７によりピストンロッド４に固着さ
れる。In the hollow part 21 of the piston 5, upper spacer cylinders 2 are arranged in order from above.
2. A circular upper fulcrum plate 24, a circular valve plate 26, a circular lower fulcrum plate 25, and a lower spacing 123 are housed, and these, together with the end wall 5a of the piston 5, have their center portions at the small diameter end 4a of the piston rod 4. The piston rod 4 is fixed to the piston rod 4 by a nut 27 that is passed through the small diameter end 4a and screwed onto the small diameter end 4a.

弁ｌｔ！ｉ２６は上、下部両支点板２４．２５よりも大
径に形成され、また上部支点板２４は下部支点板２５よ
りも大径に形成される。即ち、上部支点板２４の弁！ｆ
ｆ２６に対する支持長さは、下部支点板２５のそれより
も短く設定される。Valent! i26 is formed to have a larger diameter than both the upper and lower fulcrum plates 24, 25, and the upper fulcrum plate 24 is formed to have a larger diameter than the lower fulcrum plate 25. That is, the valve of the upper fulcrum plate 24! f
The support length for f26 is set shorter than that of the lower fulcrum plate 25.

一方、ピストン５には、弁板２６の外周端に対向してそ
れとの間に流路１６の絞り部１６ａを画成する環状突起
２８が設けられる。On the other hand, the piston 5 is provided with an annular projection 28 that faces the outer peripheral end of the valve plate 26 and defines a constricted portion 16a of the flow path 16 therebetween.

この突起２８は、ピストン５の内周面に一体に形成され
た環状の第１山部２９と、ピストン５の内周面に蝶着さ
れる環状体３１に形成された環状の第２山部３０と、両
山部２９，３０間に挟止されるリング体３２とから構成
される。そして、両山部２９．３０の頂部及びリング体
３２の内周面は略連続した平坦面に形成される。The protrusion 28 includes a first annular crest 29 integrally formed on the inner circumferential surface of the piston 5 and a second annular ridge formed on an annular body 31 hinged to the inner circumferential surface of the piston 5. 30 and a ring body 32 sandwiched between both peaks 29 and 30. The tops of both peaks 29 and 30 and the inner peripheral surface of the ring body 32 are formed into substantially continuous flat surfaces.

第３図に示すように、前記弁［２６及びリング体３２は
、一枚の円形の板ばね材から作られる。As shown in FIG. 3, the valve [26 and the ring body 32 are made from a single circular plate spring material.

即ち、一枚の円形の板ばね材の中心部に前記ピストンロ
ッド４の小径端部４ａに貫通される取付孔３３が穿設さ
れ、また同外周部に前記絞り部１６ａに相当する複数の
円弧状スリット３４が取付孔３３と同心の円周線上に並
ぶように切られ、さらに同中間部に各円弧状スリット３
４の両端から取付孔３３近くまで延びる直線状スリット
３５が切られる。That is, a mounting hole 33 that is penetrated by the small-diameter end 4a of the piston rod 4 is formed in the center of a single circular plate spring material, and a plurality of circles corresponding to the constricted portions 16a are formed in the outer periphery of the same. The arcuate slits 34 are cut so as to be lined up on a circumferential line concentric with the mounting hole 33, and each arcuate slit 3 is cut in the same middle part.
A linear slit 35 is cut from both ends of 4 to near the attachment hole 33.

而して、取付孔３３を有するボス部３６と、円弧状スリ
ット３４及び直線状スリット３５に囲まれる複数の弁片
３７とから前記弁板２６が構成され、そのボス部３６が
前記ピストンロッド４の小径端部４ａに固着される。The valve plate 26 is composed of a boss portion 36 having a mounting hole 33 and a plurality of valve pieces 37 surrounded by an arcuate slit 34 and a linear slit 35, and the boss portion 36 is connected to the piston rod 4. It is fixed to the small diameter end 4a of.

また円弧状スリット３４の外側に位置する部分により前
記リング体３２が構成され、このリング体３２及びボス
部３６は各弁片３７間を放射状に走る複数の連結片３８
により一体に連結される。Further, the ring body 32 is constituted by the portion located outside the arcuate slit 34, and the ring body 32 and the boss portion 36 are connected to a plurality of connecting pieces 38 that run radially between the respective valve pieces 37.
are connected together.

次にこの実施例の作用を説明する。Next, the operation of this embodiment will be explained.

緩衝器ｌに軸方向の圧縮荷重が加わり、ピストン５がシ
リンダ３内を下降すると、これに伴い下部油室７の油が
流路１６を通って上部油室６へ移るが、当初、最小開度
となっている弁板２６及び突起２８間の絞り部１６ａで
油の流れが絞られるため下部油室７の油圧が上昇し、減
衰力が発生する。When a compressive load in the axial direction is applied to the shock absorber l and the piston 5 descends inside the cylinder 3, the oil in the lower oil chamber 7 passes through the flow path 16 and moves to the upper oil chamber 6. Since the flow of oil is restricted by the constricted portion 16a between the valve plate 26 and the protrusion 28, which is in a constant state, the oil pressure in the lower oil chamber 7 increases and a damping force is generated.

こうして下部油室７に発生した油圧は弁板２６の下面に
作用するので、その油圧が所定値を超えて上昇すると、
弁板２６の各弁片３７が上部支点板２４の周縁を支点と
して上方へ撓まされ、その撓み量の増加に応じて絞り部
１６ａの開度が増加し、それに応じて減衰力の増加度合
が制御される。The oil pressure generated in the lower oil chamber 7 acts on the lower surface of the valve plate 26, so when the oil pressure rises beyond a predetermined value,
Each valve piece 37 of the valve plate 26 is bent upward using the peripheral edge of the upper support plate 24 as a fulcrum, and as the amount of bending increases, the opening degree of the throttle portion 16a increases, and the degree of increase in damping force increases accordingly. is controlled.

次に圧縮荷重が取除かれると緩衝器１が懸架ばね１５の
復元力で伸長するが、その伸長開始前に両袖室６，７闇
の圧力差がなくなったとき、弁板２６の各弁片３７は自
己の弾性により直ちに当初の自由状態に復帰して絞り部
１６ａの開度を再び最小にするので、緩衝器ｌの伸長、
即ちピストン５の上昇が始まると、上部油室６から下部
油室７へ油が移るとき、緩衝器１の収縮時と同様に絞り
部１６ａで油の流れが絞られるため上部油室６の油圧が
上昇し、減衰力が確実に発生する。Next, when the compressive load is removed, the shock absorber 1 expands due to the restoring force of the suspension spring 15, but before the expansion begins, when the pressure difference between the sleeve chambers 6 and 7 disappears, each valve of the valve plate 26 The piece 37 immediately returns to its original free state due to its own elasticity and minimizes the opening degree of the constriction portion 16a again, so that the expansion of the buffer l,
That is, when the piston 5 begins to rise, when oil moves from the upper oil chamber 6 to the lower oil chamber 7, the flow of oil is throttled by the constriction part 16a, similar to when the shock absorber 1 contracts, so that the oil pressure in the upper oil chamber 6 decreases. increases, and damping force is reliably generated.

そして上部油室６の油圧は弁板２６の上面に作用するの
で、その油圧が所定値を超えて上昇すると、弁板２６の
各弁片３７が下部支点板２５の周縁を支点として下方へ
撓まされ、この撓み量の増加に応じて絞り部１６ａの開
度が増加し、それに応じて減衰力の増加度合が制御され
る。The oil pressure in the upper oil chamber 6 acts on the upper surface of the valve plate 26, so when the oil pressure rises above a predetermined value, each valve piece 37 of the valve plate 26 bends downward using the periphery of the lower fulcrum plate 25 as a fulcrum. The degree of opening of the throttle portion 16a increases in accordance with the increase in the amount of deflection, and the degree of increase in the damping force is controlled accordingly.

尚、前記のような上、下部支点板２４．２５の寸法設定
により、弁板２６の下部支点板２４からの張出し量は上
部支点板２５からのそれより小さくなっているので、弁
片３７の下方への曲げ荷重は上部への曲げ荷重より大き
く、したがって、このとき得られる減衰力は緩衝器ｌの
収縮時よりも大きくなる。Furthermore, due to the dimension setting of the upper and lower fulcrum plates 24 and 25 as described above, the amount of overhang of the valve plate 26 from the lower fulcrum plate 24 is smaller than that from the upper fulcrum plate 25, so that the valve piece 37 is The downward bending load is greater than the upward bending load, and therefore the damping force obtained at this time is greater than when the shock absorber I is contracted.

ところで、弁板２６及びリング体３２は一枚の仮ばね材
から加工され、しかも弁板２６のボス部３６とリング体
３２とは連結片３５を介して一体に連結されているので
、弁板２６とリング体３２の相対位置関係は常に一定で
あり、したがって両者２６．３２間に画成される絞り部
１６ａは、緩衝弁９の緩衝器１への装着時の組立誤差の
影響を全く受けず、常に適正な寸法を保ち、減衰力特性
を安定させることができる。By the way, the valve plate 26 and the ring body 32 are processed from a single piece of temporary spring material, and the boss portion 36 of the valve plate 26 and the ring body 32 are integrally connected via the connecting piece 35. The relative positional relationship between 26 and ring body 32 is always constant, therefore, the constriction portion 16a defined between both 26 and 32 is completely unaffected by assembly errors when attaching the buffer valve 9 to the shock absorber 1. Therefore, proper dimensions can always be maintained and damping force characteristics can be stabilized.

一方、下部油室７及びオイルリザーバ８間では、ピスト
ン５の昇降によるピストンロッド４の、シリンダ３内を
占める体積変化に応じオリフィス１０を通して油の流通
が行われ１、その流速が所定値を超えるとオリフィス１
０の抵抗により減衰力が発生する。On the other hand, between the lower oil chamber 7 and the oil reservoir 8, oil flows through the orifice 10 in accordance with the change in volume of the piston rod 4 occupying the inside of the cylinder 3 due to the rise and fall of the piston 5, and the flow rate exceeds a predetermined value. and orifice 1
A damping force is generated due to zero resistance.

尚、緩衝弁９は、オリフィス１０に代えて仕切部材１７
に設けることもできる。Note that the buffer valve 9 has a partition member 17 instead of the orifice 10.
It can also be provided in

Ｃ１発明の効果 以上のように本発明によれば、前記緩衝弁を、仕切部材
に固着されるボス部と、このボス部から放射状に突出し
、前記両油室間の圧力差発生時に低圧側へ撓む複数の弁
片と、これら弁片を囲繞して仕切部材に固着され、これ
ら弁片の可動端との間に前記流路の絞り部を画成するリ
ング体と、前記弁片間に配置されて前記ボス部及びリン
グ体間を一体に連結する連結片とから構成したので、単
一の緩衝弁をもって収縮減衰力及び伸長減衰力を発生さ
せることができ、したがって部品点数が半減してコスト
の低減に大いに寄与することができ、しかも緩衝器の収
縮及び伸長が高速で繰返される場合でも、流路の絞り部
は弁部材により必ず最小開度の状態から制御されること
になり、常に安定した緩衝性能を得ることができる。C1 Effects of the Invention As described above, according to the present invention, the buffer valve has a boss portion fixed to the partition member, and protrudes radially from the boss portion, so that when a pressure difference occurs between the two oil chambers, the buffer valve is moved to the low pressure side. A plurality of flexible valve pieces, a ring body that surrounds these valve pieces and is fixed to a partition member and defines a constricted part of the flow path between the movable ends of these valve pieces, and between the valve pieces Since the structure includes a connecting piece that is arranged to integrally connect the boss part and the ring body, a single buffer valve can generate contraction damping force and extension damping force, and the number of parts can be reduced by half. This can greatly contribute to cost reduction, and even if the shock absorber is repeatedly contracted and expanded at high speed, the flow path throttle section will always be controlled from the minimum opening state by the valve member, so it will always be possible to reduce costs. Stable buffer performance can be obtained.

しかも、弁片を支持するボス部とリング体との一体化に
より、緩衝弁の緩衝器への装着時の組立誤差の影響を受
けることなく弁片及びリング体間の絞り部を常に適正な
寸法に保つことができ、これにより減衰力特性の安定化
に大いに寄与し得る。Moreover, by integrating the boss part that supports the valve piece with the ring body, the throttle part between the valve piece and the ring body can always be kept at the appropriate size without being affected by assembly errors when installing the buffer valve to the shock absorber. This can greatly contribute to stabilizing the damping force characteristics.

【図面の簡単な説明】[Brief explanation of the drawing]

図面は本発明の一実施例を示すもので、第１図は自動車
用油圧緩衝器の要部を縦断した側面図、第２図はＨ１ｉ
弁周辺の拡大縦断面図、第３図は緩衝弁の斜視図である
。 １・・・油圧緩衝器、５・・・仕切部材としてのピスト
ン、６・・・一方の油室、７・・・他方の油室、９・・
・１Ｎ　！３ｉ弁、１６・・・流路、）６ａ・・・絞り
部、２６・・・弁板、３２・・・リング体、３６・・・
ボス部、３７・・・弁片、３８・・・連結片The drawings show one embodiment of the present invention, and FIG. 1 is a longitudinal side view of the main parts of a hydraulic shock absorber for an automobile, and FIG.
FIG. 3 is an enlarged vertical cross-sectional view of the vicinity of the valve, and FIG. 3 is a perspective view of the buffer valve. DESCRIPTION OF SYMBOLS 1... Hydraulic shock absorber, 5... Piston as a partition member, 6... One oil chamber, 7... Other oil chamber, 9...
・1N! 3i valve, 16... flow path, ) 6a... throttle part, 26... valve plate, 32... ring body, 36...
Boss part, 37... Valve piece, 38... Connection piece

Claims (1)

【特許請求の範囲】 少なくとも二つの油室と、この両油室間を連通する流路
を有して両油室間を仕切る仕切部材と、前記流路に生じ
る油の流れを制御すべく前記仕切部材に設けられた緩衝
弁とを備えた油圧緩衝器において、 前記緩衝弁を、仕切部材に固着されるボス部と、このボ
ス部から放射状に突出し、前記両油室間の圧力差発生時
に低圧側へ撓む複数の弁片と、これら弁片を囲繞して仕
切部材に固着され、これら弁片の可動端との間に前記流
路の絞り部を画成するリング体と、前記弁片間に配置さ
れて前記ボス部及びリング体間を一体に連結する連結片
とから構成したことを特徴とする、油圧緩衝器。[Scope of Claims] At least two oil chambers; a partition member having a flow path communicating between the two oil chambers to partition the two oil chambers; In a hydraulic shock absorber equipped with a buffer valve provided on a partition member, the buffer valve includes a boss portion fixed to the partition member and a boss portion that projects radially from the boss portion, so that the buffer valve is configured to have a boss portion fixed to the partition member and project radially from the boss portion, so that when a pressure difference occurs between the two oil chambers, a plurality of valve pieces that bend toward the low pressure side; a ring body that surrounds these valve pieces and is fixed to a partition member and defines a constricted portion of the flow path between the movable ends of these valve pieces; A hydraulic shock absorber comprising a connecting piece disposed between the pieces to integrally connect the boss portion and the ring body.