JP2009052702A

JP2009052702A - Damping force adjustable hydraulic shock absorber

Info

Publication number: JP2009052702A
Application number: JP2007221700A
Authority: JP
Inventors: Tsutomu Naito; 力内藤
Original assignee: Showa Corp
Current assignee: Showa Corp
Priority date: 2007-08-28
Filing date: 2007-08-28
Publication date: 2009-03-12

Abstract

PROBLEM TO BE SOLVED: To adjust extension side damping force and compression side damping force by simple structure in a damping force adjustable hydraulic shock absorber. SOLUTION: In this damping force adjustable hydraulic shock absorber, an extension side back pressure chamber 61 and a compression side back pressure chamber 71 are provided on the back side of an extension side damping valve 33 in a first piston 23 and on the back side of a compression side damping valve 43 in a second piston 27, respectively. A piston rod 13 is provided with a by-pass passage 80, a variable throttle valve 81 is provided in an intermediate part of the by-pass passage 80, and the pressure in the extension side back pressure chamber 61 and in the compression side back pressure chamber 71 is controlled by adjusting the throttling degree of the variable throttle valve 81, thereby adjusting the extension side damping force and the compression side damping force. COPYRIGHT: (C)2009,JPO&INPIT

Description

本発明は減衰力調整式油圧緩衝器に関する。 The present invention relates to a damping force adjusting hydraulic shock absorber.

減衰力調整式油圧緩衝器として、特許文献１に記載の如く、シリンダにピストンロッドを挿入し、ピストンロッドに固定したピストンによりシリンダ内をロッド側室とピストン側室に区画し、ロッド側室とピストン側室はピストンに設けた伸側流路及び該伸側流路を開閉する伸側減衰バルブと、圧側流路及び該圧側流路を開閉する圧側減衰バルブのそれぞれを介して連通されてなる減衰力調整式油圧緩衝器において、伸側減衰バルブの伸側流路に対する背面側と圧側減衰バルブの圧側流路に対する背面側のそれぞれに、伸側背圧室と圧側背圧室のそれぞれを設け、ピストンロッドにピストンの伸側流路と圧側流路を迂回してロッド側室とピストン側室を連絡するバイパス路を設け、バイパス路の中間部に伸側背圧室と圧側背圧室を連絡してなるものがある。このバイパス路は、第１のチェック弁を介してピストン側室からの油の流れを許容するとともに、第２のチェック弁を介してロッド側室からの油の流れを許容する。更に、伸側背圧室と圧側背圧室の圧力を制御する圧力制御弁をバイパス路に連通するリリーフ室に設け、圧力制御弁のリリーフ室からロッド側室への油の流れのみを許容する第３のチェック弁と、圧力制御弁のリリーフ室からピストン側室への油の流れのみを許容する第４のチェック弁とを設けている。特許文献１に記載の減衰力調整式油圧緩衝器では、圧力制御弁の設定圧力が低いときには、伸側減衰力と圧側減衰力の双方が低くなり、圧力制御弁の設定圧力が高いときには、伸側減衰力と圧側減衰力の双方が高くなる。
特開平8-4818号 As described in Patent Document 1, as a damping force adjustment type hydraulic shock absorber, a piston rod is inserted into a cylinder, and the inside of the cylinder is divided into a rod side chamber and a piston side chamber by a piston fixed to the piston rod. A damping force adjusting type connected to each other via an extension side flow path provided on the piston, an extension side damping valve for opening and closing the extension side flow path, and a pressure side flow path and a pressure side damping valve for opening and closing the pressure side flow path. In the hydraulic shock absorber, an extension side back pressure chamber and a pressure side back pressure chamber are provided on the back side of the extension side damping valve on the extension side flow path and on the back side of the pressure side damping valve on the pressure side flow path, respectively. A bypass passage that bypasses the extension side flow path and the pressure side flow path of the piston and connects the rod side chamber and the piston side chamber is provided, and the extension back pressure chamber and the pressure side back pressure chamber are connected to the middle part of the bypass path. There are things. This bypass passage allows the flow of oil from the piston side chamber via the first check valve and allows the flow of oil from the rod side chamber via the second check valve. In addition, a pressure control valve for controlling the pressure in the extension side back pressure chamber and the pressure side back pressure chamber is provided in the relief chamber communicating with the bypass passage, and only the flow of oil from the relief chamber of the pressure control valve to the rod side chamber is allowed. And a fourth check valve that allows only the flow of oil from the relief chamber of the pressure control valve to the piston side chamber. In the damping force adjustment type hydraulic shock absorber described in Patent Document 1, when the set pressure of the pressure control valve is low, both the extension side damping force and the compression side damping force are low, and when the set pressure of the pressure control valve is high, the extension is performed. Both the side damping force and the compression side damping force are increased.
JP-A-8-4818

特許文献１に記載の減衰力調整式油圧緩衝器では、ピストンロッドに設けるバイパス路に圧力制御弁を設けるとともに、このバイパス路をピストン側室とロッド側室のそれぞれに連通する通路に第１と第２のチェック弁を設け、圧力制御弁のリリーフ室をロッド側室とピストン側室のそれぞれに連通する通路に第３と第４のチェック弁を設ける必要があり、構成部品の加工工程、組立工程が多大になり、複雑である。 In the damping force adjustment type hydraulic shock absorber described in Patent Document 1, a pressure control valve is provided in a bypass passage provided in the piston rod, and the bypass passage is connected to a passage communicating with each of the piston side chamber and the rod side chamber. It is necessary to provide the third and fourth check valves in the passages that connect the relief chamber of the pressure control valve to each of the rod side chamber and the piston side chamber. It is complicated.

本発明の課題は、減衰力調整式油圧緩衝器において、簡易な構造により、伸側減衰力と圧側減衰力を調整することにある。 An object of the present invention is to adjust an extension side damping force and a compression side damping force with a simple structure in a damping force adjusting hydraulic shock absorber.

請求項１の発明は、シリンダにピストンロッドを挿入し、ピストンロッドに第１と第２のピストンを固定し、シリンダの内部に、第１のピストンと第２のピストンに挟まれる中間室と、第１のピストンの中間室に対する反対側に区画されるロッド側室と、第２のピストンの中間室に対する反対側に区画されるピストン側室を設け、第１のピストンはロッド側室と中間室を連通可能にする伸側流路と圧側流路を備えるとともに、伸側流路を伸側行程で開く伸側減衰バルブと、圧側流路を伸側行程では閉じ、圧側行程で開く伸側チェック弁を有し、第２のピストンはピストン側室と中間室を連通可能にする圧側流路と伸側流路を備えるとともに、圧側流路を圧側行程で開く圧側減衰バルブと、伸側流路を圧側行程では閉じ、伸側行程では開く圧側チェック弁を有してなる減衰力調整式油圧緩衝器であって、第１のピストンにおける伸側減衰バルブの伸側流路に対する背面側と、第２のピストンにおける圧側減衰バルブの圧側流路に対する背面側のそれぞれに、伸側背圧室と圧側背圧室のそれぞれを設け、ピストンロッドに第１と第２の両ピストンの伸側流路と圧側流路を迂回してロッド側室とピストン側室を連絡するバイパス路を設け、バイパス路の中間部に伸側背圧室と圧側背圧室を連絡し、バイパス路における伸側背圧室への連絡口と圧側背圧室への連絡口に挟まれる中間部に可変絞り弁を設け、可変絞り弁の絞り度の調整により伸側背圧室と圧側背圧室の圧力を制御することにより、伸側減衰力と圧側減衰力を調整可能にするようにしたものである。 The invention of claim 1 inserts a piston rod into a cylinder, fixes the first and second pistons to the piston rod, an intermediate chamber sandwiched between the first piston and the second piston inside the cylinder, A rod side chamber defined on the opposite side to the intermediate chamber of the first piston and a piston side chamber defined on the opposite side to the intermediate chamber of the second piston are provided, and the first piston can communicate with the rod side chamber and the intermediate chamber. With an extension side damping valve that opens the extension side channel in the extension side stroke, and an extension side check valve that closes the pressure side channel in the extension side stroke and opens it in the compression side stroke The second piston includes a pressure side passage and an extension side passage that allow the piston side chamber and the intermediate chamber to communicate with each other, a pressure side damping valve that opens the pressure side passage in the pressure side stroke, and an extension side passage in the pressure side stroke. Close side, open on extension side A damping force adjustment type hydraulic shock absorber having a check valve, the back side of the first piston with respect to the expansion side flow path of the expansion side damping valve, and the pressure side flow path of the compression side damping valve with the second piston. Each of the back side pressure chamber and the pressure side back pressure chamber is provided on the back side, and the rod side chamber and the piston side chamber bypass the extension side flow channel and the pressure side flow channel of the first and second pistons on the piston rod. A bypass path is established to connect the extension side back pressure chamber and the compression side back pressure chamber to the middle of the bypass path, and the connection port to the extension side back pressure chamber and the pressure side back pressure chamber in the bypass path A variable throttle valve is provided in the intermediate part, and by adjusting the throttle degree of the variable throttle valve, the extension side pressure and compression side damping force can be adjusted by controlling the pressure in the extension side back pressure chamber and the pressure side back pressure chamber. It is what you do.

請求項２の発明は、請求項１の発明において更に、前記伸側背圧室と圧側背圧室のそれぞれが、伸側減衰バルブと圧側減衰バルブそれぞれのためのバルブストッパと、それらバルブストッパの外周に設けたバックアップカラーにより形成され、各バックアップカラーはスプリングにより伸側減衰バルブと圧側減衰バルブのそれぞれに付勢され、伸側減衰バルブは伸側流路に臨む受圧面積を伸側背圧室に臨む受圧面積より大きくし、圧側減衰バルブは圧側流路に臨む受圧面積を圧側背圧室に臨む受圧面積より大きくしてなるようにしたものである。 According to a second aspect of the present invention, in the first aspect of the present invention, each of the extension-side back pressure chamber and the compression-side back pressure chamber includes a valve stopper for each of the extension-side damping valve and the compression-side damping valve, and It is formed by a backup collar provided on the outer periphery, and each backup collar is urged by a spring to each of the expansion side damping valve and the compression side damping valve, and the expansion side damping valve has a pressure receiving area facing the expansion side flow path. The pressure side damping valve is configured such that the pressure receiving area facing the pressure side flow path is larger than the pressure receiving area facing the pressure side back pressure chamber.

（請求項１）
(a)可変絞り弁の絞り度の調整により伸側減衰バルブと圧側減衰バルブを閉じ方向に押さえる伸側背圧室と圧側背圧室の圧力を制御することにより、伸側減衰力と圧側減衰力を調整できる。即ち、バイパス路における伸側背圧室への連絡口と圧側背圧室への連絡口に挟まれる中間部に可変絞り弁を設けたことにより、可変絞り弁の絞り度が開き側に設定されると伸側背圧室と圧側背圧室の圧力がともに低くなって伸側減衰力と圧側減衰力をともに低く調整できる。他方、可変絞り弁の絞り度が閉じ側に設定されると伸側背圧室と圧側背圧室の圧力がともに高くなって伸側減衰力と圧側減衰力をともに高く調整できる。 (Claim 1)
(a) By adjusting the throttle degree of the variable throttle valve, the expansion side damping pressure and compression side damping force and compression side damping are controlled by controlling the pressure in the expansion side back pressure chamber and compression side back pressure chamber that press the expansion side damping valve and compression side damping valve in the closing direction. You can adjust the power. That is, by providing a variable throttle valve at the intermediate part between the communication port to the extension side back pressure chamber and the communication port to the compression side back pressure chamber in the bypass passage, the throttle degree of the variable throttle valve is set to the open side. As a result, the pressures in the extension-side back pressure chamber and the compression-side back pressure chamber both become low, and both the extension-side damping force and the compression-side damping force can be adjusted to be low. On the other hand, when the degree of throttling of the variable throttle valve is set to the closed side, the pressures in the extension-side back pressure chamber and the compression-side back pressure chamber both increase, and both the extension-side damping force and the compression-side damping force can be adjusted to be high.

(b)バイパス路の中間部に設けた可変絞り弁により伸側背圧室と圧側背圧室の圧力を制御するものであり、バイパス路の入口に設けた固定オリフィスにより背圧室の圧力を調整するものに比し、伸側背圧室と圧側背圧室の圧力を遅れなく制御し、伸側減衰力と圧側減衰力の調整の応答性を向上できる。 (b) The pressure in the expansion side pressure chamber and the pressure side back pressure chamber is controlled by a variable throttle valve provided in the middle of the bypass passage, and the pressure in the back pressure chamber is controlled by a fixed orifice provided at the inlet of the bypass passage. Compared with the one to be adjusted, the pressures in the extension-side back pressure chamber and the compression-side back pressure chamber can be controlled without delay, and the response of adjusting the extension-side damping force and the compression-side damping force can be improved.

(c)可変絞り弁の絞り度の調整により伸側背圧室と圧側背圧室の圧力を制御することにより、伸側減衰バルブと圧側減衰バルブの開弁圧を簡易な構造により自在に制御できる。これにより、伸・圧減衰力を遅れなくスムースに、大小広い範囲に渡り、無段階に調整でき、ピストンの微低速域から調整できる。伸側背圧室と圧側背圧室の圧力を制御することで、減衰バルブ自体による減衰力を小さく設定でき、減衰バルブの開弁圧を上記圧力の制御により調整でき、伸・圧減衰力を微低速域から高速域まで無段階に調整できる。 (c) By controlling the throttle pressure of the variable throttle valve to control the pressure in the expansion-side back pressure chamber and the pressure-side back pressure chamber, the opening pressure of the expansion-side damping valve and the compression-side damping valve can be freely controlled with a simple structure. it can. As a result, the extension / pressure damping force can be adjusted smoothly without delay over a wide range of large and small, and can be adjusted from the very low speed range of the piston. By controlling the pressure in the expansion-side back pressure chamber and the compression-side back pressure chamber, the damping force by the damping valve itself can be set small, and the valve opening pressure of the damping valve can be adjusted by controlling the above-mentioned pressure. Stepless adjustment is possible from very low speed to high speed.

(d)第１と第２の２つのピストンを設けるだけで、各ピストンに複雑な流路等を設ける必要がないし、ピストンロッドに設けるバイパス路も唯１つで足りる。構成部品の加工工数、組立工数も多大にならず、単純になる。 (d) By only providing the first and second pistons, it is not necessary to provide a complicated flow path or the like for each piston, and only one bypass path is required for the piston rod. The number of processing steps and assembly steps for the component parts are not increased, and it is simplified.

（請求項２）
(e)伸側背圧室と圧側背圧室のそれぞれが、伸側減衰バルブと圧側減衰バルブそれぞれのためのバルブストッパと、それらバルブストッパの外周に設けたバックアップカラーにより形成され、各バックアップカラーはスプリングにより伸側減衰バルブと圧側減衰バルブのそれぞれに付勢され、伸側減衰バルブは伸側流路に臨む受圧面積を伸側背圧室に臨む受圧面積より大きくし、圧側減衰バルブは圧側流路に臨む受圧面積を圧側背圧室に臨む受圧面積より大きくした。従って、伸側行程で、伸側流路と伸側背圧室の圧力がともに上がったとき、伸側減衰バルブの上述の受圧面積の差により伸側背圧室の側のバックアップカラーが押し下げられ、このバックアップカラーがバックアップしている伸側減衰バルブを開弁し、伸側減衰力の上限（最大減衰力）を設定できる。また、圧側行程で、圧側流路と圧側背圧室の圧力がともに上がったとき、圧側減衰バルブの上述の受圧面積の差により圧側背圧室の側のバックアップカラーが押し下げられ、このバックアップカラーがバックアップしている圧側減衰バルブを開弁し、圧側減衰力の上限（最大減衰力）を設定できる。 (Claim 2)
(e) Each of the expansion-side back pressure chamber and the compression-side back pressure chamber is formed by a valve stopper for each of the expansion-side damping valve and the compression-side damping valve and a backup collar provided on the outer periphery of each valve stopper. Is urged by the spring to each of the expansion side damping valve and the pressure side damping valve. The expansion side damping valve makes the pressure receiving area facing the expansion side flow path larger than the pressure receiving area facing the expansion side back pressure chamber, and the pressure side damping valve is the compression side The pressure receiving area facing the flow path was made larger than the pressure receiving area facing the compression side back pressure chamber. Therefore, when the pressure in the expansion side flow path and the expansion side back pressure chamber rises during the expansion side stroke, the backup collar on the expansion side back pressure chamber side is pushed down due to the difference in the pressure receiving area of the expansion side damping valve. The extension side damping valve backed up by this backup collar is opened, and the upper limit (maximum damping force) of the extension side damping force can be set. In addition, when both the pressure side flow path and the pressure side back pressure chamber rise in the pressure side stroke, the pressure collar on the pressure side back pressure chamber side is pushed down due to the difference in the pressure receiving area of the pressure side damping valve. The backup pressure side damping valve can be opened to set the upper limit (maximum damping force) of the compression side damping force.

図１は減衰力調整式油圧緩衝器を示す断面図、図２は図１の減衰力調整構造を示す断面図、図３は図２の要部拡大図、図４は可変絞り弁の絞り度を開き側に設定した状態で、（Ａ）は伸側行程を示す断面図、（Ｂ）は圧側行程を示す断面図、図５は可変絞り弁の絞り度を閉じ側に設定した状態で、（Ａ）は伸側減衰力を示す断面図、（Ｂ）は圧側減衰力を示す断面図である。 1 is a cross-sectional view showing a damping force adjusting hydraulic shock absorber, FIG. 2 is a cross-sectional view showing the damping force adjusting structure of FIG. 1, FIG. 3 is an enlarged view of the main part of FIG. 2, and FIG. (A) is a cross-sectional view showing the extension side stroke, (B) is a cross-sectional view showing the compression side stroke, and FIG. 5 is a state where the throttle degree of the variable throttle valve is set to the close side. (A) is sectional drawing which shows the extension side damping force, (B) is sectional drawing which shows the compression side damping force.

減衰力調整式油圧緩衝器１０は、図１、図２に示す如く、ダンパチューブ１１にシリンダ１２を内蔵した二重管からなる複筒式であり、シリンダ１２にピストンロッド１３を挿入し、ダンパチューブ１１の下部に車軸側取付部を備えるとともに、ピストンロッド１３の上部に車体側取付部１４を備え、車両の懸架装置を構成する。 As shown in FIGS. 1 and 2, the damping force adjusting hydraulic shock absorber 10 is a double-tube type composed of a double tube in which a cylinder 12 is built in a damper tube 11, and a piston rod 13 is inserted into the cylinder 12 to An axle side attachment portion is provided at the lower portion of the tube 11, and a vehicle body side attachment portion 14 is provided at the upper portion of the piston rod 13 to constitute a vehicle suspension device.

油圧緩衝器１０は、ダンパチューブ１１の外周の下スプリングシート１５と、ピストンロッド１３の上端部の車体側取付部１４に設けられた上スプリングシート（不図示）の間に懸架ばね１６を介装する。 The hydraulic shock absorber 10 has a suspension spring 16 interposed between a lower spring seat 15 on the outer periphery of the damper tube 11 and an upper spring seat (not shown) provided on the vehicle body side mounting portion 14 at the upper end portion of the piston rod 13. To do.

油圧緩衝器１０は、シリンダ１２に挿入されるピストンロッド１３のためのロッドガイド１７、ブッシュ１８、オイルシール１９を、ダンパチューブ１１の上端加締部１１Ａとシリンダ１２の上端部の間に挟圧固定している。 The hydraulic shock absorber 10 clamps a rod guide 17, a bush 18, and an oil seal 19 for the piston rod 13 inserted into the cylinder 12 between the upper end crimped portion 11 A of the damper tube 11 and the upper end portion of the cylinder 12. It is fixed.

減衰力調整式油圧緩衝器１０は、ピストンバルブ装置２０とボトムバルブ装置５０を有し、それらが発生する減衰力により、懸架ばね１６による衝撃力の吸収に伴うピストンロッド１３の伸縮振動を制振する。 The damping force adjusting hydraulic shock absorber 10 includes a piston valve device 20 and a bottom valve device 50, and the damping force generated by them controls vibrations of the piston rod 13 caused by absorption of impact force by the suspension spring 16. To do.

（ピストンバルブ装置２０）
ピストンバルブ装置２０は、ピストンロッド１３のシリンダ１２への挿入端の外周に螺着されて固定されるピストンボルト２１を有し、ピストンボルト２１の外周にスペーサ２２、第１のピストン２３、バルブストッパ２４、カラー２５、バルブストッパ２６、第２のピストン２７、スペーサ２８を挿着し、これらをピストンボルト２１に螺着される袋ナット２９によりピストンボルト２１の基端段差部との間に挟圧固定する。 (Piston valve device 20)
The piston valve device 20 has a piston bolt 21 that is screwed and fixed to the outer periphery of the insertion end of the piston rod 13 into the cylinder 12. A spacer 22, a first piston 23, and a valve stopper are provided on the outer periphery of the piston bolt 21. 24, collar 25, valve stopper 26, second piston 27, and spacer 28 are inserted and clamped between the base end step portion of the piston bolt 21 by a cap nut 29 screwed to the piston bolt 21. Fix it.

ピストンバルブ装置２０は、シリンダ１２の内部に、第１のピストン２３と第２のピストン２７に挟まれる中間室１２Ｃと、第１のピストン２３の中間室１２Ｃに対する反対側に区画されるロッド側室１２Ａと、第２のピストン２７の中間室１２Ｃに対する反対側に区画されるピストン側室１２Ｂを設ける。 The piston valve device 20 includes, in the cylinder 12, an intermediate chamber 12C sandwiched between the first piston 23 and the second piston 27, and a rod side chamber 12A partitioned on the opposite side of the first piston 23 with respect to the intermediate chamber 12C. And a piston-side chamber 12B that is partitioned on the opposite side of the second piston 27 with respect to the intermediate chamber 12C.

第１のピストン２３は、ロッド側室１２Ａと中間室１２Ｃを連通可能にする伸側流路３１と圧側流路３２を備えるとともに、伸側流路３１を伸側行程で開くディスク状の伸側減衰バルブ３３と、圧側流路３２を伸側行程では閉じ、圧側行程で開く伸側チェック弁３４を有する。伸側減衰バルブ３３はその内周側を第１のピストン２３とバルブストッパ２４の間に挟持される。伸側チェック弁３４はその内周側を第１のピストン２３とスペーサ２２の間に挟持される。 The first piston 23 is provided with an extension side channel 31 and a pressure side channel 32 that allow the rod side chamber 12A and the intermediate chamber 12C to communicate with each other, and the disk-like extension side damping opens the extension side channel 31 in the extension side stroke. The valve 33 and the expansion side check valve 34 are closed in the expansion side stroke and opened in the compression side stroke. The expansion-side damping valve 33 is sandwiched between the first piston 23 and the valve stopper 24 on the inner peripheral side. The extension side check valve 34 is sandwiched between the first piston 23 and the spacer 22 on the inner peripheral side thereof.

第２のピストン２７は、ピストン側室１２Ｂと中間室１２Ｃを連通可能にする圧側流路４１と伸側流路４２を備えるとともに、圧側流路４１を圧側行程で開くディスク状の圧側減衰バルブ４３と、伸側流路４２を圧側行程では閉じ、伸側行程では開く圧側チェック弁４４を有する。圧側減衰バルブ４３はその内周側を第２のピストン２７とバルブストッパ２６の間に挟持される。圧側チェック弁４４はその内周側を第２のピストン２７とスペーサ２８の間に挟持される。 The second piston 27 includes a pressure side channel 41 and an extension side channel 42 that allow the piston side chamber 12B and the intermediate chamber 12C to communicate with each other, and a disk-like pressure side damping valve 43 that opens the pressure side channel 41 in the pressure side stroke. The pressure side check valve 44 is closed in the pressure side stroke and opened in the pressure side stroke. The inner side of the compression side damping valve 43 is sandwiched between the second piston 27 and the valve stopper 26. The inner side of the pressure side check valve 44 is sandwiched between the second piston 27 and the spacer 28.

従って、伸長時には、ロッド側室１２Ａの油が、第１のピストン２３の伸側流路３１を通り、伸側減衰バルブ３３を撓み変形させて開き、中間室１２Ｃ経由で、第２のピストン２７の伸側流路４２を通り、圧側チェック弁４４を開いてピストン側室１２Ｂに導かれ、伸側減衰力を発生させる。また、圧縮時には、ピストン側室１２Ｂの油が、第２のピストン２７の圧側流路４１を通り、圧側減衰バルブ４３を撓み変形させて開き、中間室１２Ｃ経由で、第１のピストン２３の圧側流路３２を通り、伸側チェック弁３４を開いてロッド側室１２Ａに導かれ、圧側減衰力を発生させる。 Therefore, at the time of extension, the oil in the rod side chamber 12A passes through the extension side flow path 31 of the first piston 23, bends and opens the extension side damping valve 33, and opens the second piston 27 via the intermediate chamber 12C. The pressure side check valve 44 is opened through the extension side flow path 42 and guided to the piston side chamber 12B, and an extension side damping force is generated. Further, at the time of compression, the oil in the piston side chamber 12B passes through the pressure side flow path 41 of the second piston 27, bends and deforms the pressure side damping valve 43, and opens through the intermediate chamber 12C to the pressure side flow of the first piston 23. Through the passage 32, the extension side check valve 34 is opened and guided to the rod side chamber 12A to generate a compression side damping force.

（ボトムバルブ装置５０）
油圧緩衝器１０は、ダンパチューブ１１とシリンダ１２の間隙をリザーバ室１２Ｄとし、このリザーバ室１２Ｄの内部を油室とガス室に区画している。そして、ボトムバルブ装置５０は、シリンダ１２の内部のピストン側室１２Ｂとリザーバ室１２Ｄとを仕切るボトムピース５１をシリンダ１２の下端部とダンパチューブ１１の底部との間に配置し、ダンパチューブ１１の底部とボトムピース５１の間の空間をボトムピース５１に設けた流路によりリザーバ室１２Ｄに連絡可能にする。 (Bottom valve device 50)
In the hydraulic shock absorber 10, a gap between the damper tube 11 and the cylinder 12 is defined as a reservoir chamber 12D, and the interior of the reservoir chamber 12D is divided into an oil chamber and a gas chamber. The bottom valve device 50 includes a bottom piece 51 that partitions the piston-side chamber 12B and the reservoir chamber 12D inside the cylinder 12 between the lower end portion of the cylinder 12 and the bottom portion of the damper tube 11, and the bottom portion of the damper tube 11. The space between the bottom piece 51 and the bottom piece 51 can be communicated with the reservoir chamber 12D through a flow path provided in the bottom piece 51.

ボトムバルブ装置５０は、ボトムピース５１に設けた圧側流路５１Ａと伸側流路（不図示）をそれぞれ開閉するボトムバルブとしての、ディスクバルブ５２とチェックバルブ５３を備える。 The bottom valve device 50 includes a disk valve 52 and a check valve 53 as bottom valves for opening and closing a pressure side channel 51A and an extension side channel (not shown) provided in the bottom piece 51, respectively.

そして、伸長時には、シリンダ１２から退出するピストンロッド１３の退出容積分の油が、チェックバルブ５３を押し開き、リザーバ室１２Ｄからボトムピース５１の伸側流路（不図示）経由でピストン側室１２Ｂに補給される。圧縮時には、シリンダ１２に進入するピストンロッド１３の進入容積分の油が、ピストン側室１２Ｂからボトムピース５１の圧側流路５１Ａを通ってディスクバルブ５２を撓み変形させて開き、リザーバ室１２Ｄへ押出され、圧側減衰力を得る。 At the time of extension, the oil corresponding to the retraction volume of the piston rod 13 that retreats from the cylinder 12 pushes open the check valve 53 and enters the piston side chamber 12B from the reservoir chamber 12D via the expansion side flow path (not shown) of the bottom piece 51. To be replenished. At the time of compression, the oil corresponding to the volume of the piston rod 13 entering the cylinder 12 is opened from the piston side chamber 12B through the pressure side flow path 51A of the bottom piece 51 by bending and deforming the disk valve 52 and pushed into the reservoir chamber 12D. Get the compression side damping force.

尚、油圧緩衝器１０にあっては、シリンダ１２のロッド側室１２Ａに位置するピストンロッド１３まわりで、ピストン２３の側（上側）に固定されたリバウンドシート５６の上に、ピストンロッド１３の伸切り時（油圧緩衝器１０の最伸長状態）に圧縮変形せしめられるリバウンドラバー５７を備えている。 In the hydraulic shock absorber 10, the piston rod 13 is stretched around the piston rod 13 positioned in the rod side chamber 12 A of the cylinder 12 and on the rebound sheet 56 fixed to the piston 23 side (upper side). A rebound rubber 57 that is compressed and deformed at the time (the maximum extension state of the hydraulic shock absorber 10) is provided.

しかるに、油圧緩衝器１０は、ピストンバルブ装置２０の伸・圧減衰力を調整するための減衰力調整装置６０を以下の如くに備える。 However, the hydraulic shock absorber 10 includes a damping force adjusting device 60 for adjusting the extension / pressure damping force of the piston valve device 20 as follows.

減衰力調整装置６０は、図３に示す如く、第１のピストン２３における伸側減衰バルブ３３の伸側流路３１に対する背面側と、第２のピストン２７における圧側減衰バルブ４３の圧側流路４１に対する背面側のそれぞれに、伸側背圧室６１と圧側背圧室７１のそれぞれを設ける。本実施例では、伸側背圧室６１と圧側背圧室７１のそれぞれが、伸側減衰バルブ３３と圧側減衰バルブ４３それぞれの背面に設けたバルブストッパ２４、２６と、それらバルブストッパ２４、２６の外周に摺動隙間を介して摺動するように設けたバックアップカラー６２、７２により区画されて形成され、各バックアップカラー６２、７２の背面に設けた板ばね６３、７３（スプリング）により各バックアップカラー６２、７２の正面を伸側減衰バルブ３３と圧側減衰バルブ４３のそれぞれに付勢されて押し当てられる。環状板ばね６３の環状中央部がバルブストッパ２４とカラー２５の間に挟圧固定され、該板ばね６３の外縁部がバックアップカラー６２に予圧接する弾性曲がり状態で当接する。環状板ばね７３の環状中央部がバルブストッパ２６とカラー２５の間に挟圧固定され、該板ばね７３の外縁部がバックアップカラー７２に予圧接する弾性曲がり状態で当接する。このとき、伸側減衰バルブ３３と圧側減衰バルブ４３のそれぞれが伸側流路３１と圧側流路４１のそれぞれに臨む受圧面積は、伸側背圧室６１と圧側背圧室７１のそれぞれに臨む受圧面積より大きくする。 As shown in FIG. 3, the damping force adjusting device 60 includes a back side of the extension side damping valve 33 in the first piston 23 with respect to the extension side channel 31 and a pressure side channel 41 of the compression side damping valve 43 in the second piston 27. An extension side back pressure chamber 61 and a pressure side back pressure chamber 71 are provided on each of the back surfaces of the pressure side. In this embodiment, each of the expansion side back pressure chamber 61 and the pressure side back pressure chamber 71 includes valve stoppers 24 and 26 provided on the back surfaces of the expansion side damping valve 33 and the pressure side damping valve 43, respectively, and these valve stoppers 24 and 26. Each of the backup collars 63, 73 (spring) provided on the back surface of each of the backup collars 62, 72 is partitioned and formed by backup collars 62, 72 provided so as to slide on the outer periphery of the backup collars. The front surfaces of the collars 62 and 72 are urged and pressed against the extension side damping valve 33 and the compression side damping valve 43, respectively. An annular central portion of the annular leaf spring 63 is clamped and fixed between the valve stopper 24 and the collar 25, and an outer edge portion of the leaf spring 63 comes into contact with the backup collar 62 in an elastic bent state. The annular central portion of the annular leaf spring 73 is clamped and fixed between the valve stopper 26 and the collar 25, and the outer edge portion of the leaf spring 73 contacts the backup collar 72 in an elastic bent state. At this time, the pressure receiving areas that the expansion side damping valve 33 and the compression side attenuation valve 43 respectively face the expansion side flow path 31 and the pressure side flow path 41 respectively face the expansion side back pressure chamber 61 and the pressure side back pressure chamber 71. Make it larger than the pressure receiving area.

減衰力調整装置６０は、ピストンロッド１３（ピストンボルト２１及び袋ナット２９）に第１と第２の両ピストン２３、２７の伸側流路３１、４２と圧側流路３２、４１と中間室１２Ｃを迂回してロッド側室１２Ａとピストン側室１２Ｂを連絡可能にするバイパス路８０を設ける。バイパス路８０の中間部に伸側背圧室６１と圧側背圧室７１を連絡する。バイパス路８０は、ピストンボルト２１に設けた孔状連絡口６１Ａ、バルブストッパ２４の内周環状溝６１Ｂ、孔６１Ｃを順に連通させて伸側背圧室６１に連絡する。また、バイパス路８０は、ピストンボルト２１に設けた孔状連絡口７１Ａ、バルブストッパ２６の内周環状溝７１Ｂ、孔７１Ｃを順に連通させて圧側背圧室７１に連絡する。 The damping force adjusting device 60 is connected to the piston rod 13 (piston bolt 21 and cap nut 29) on the extension side passages 31 and 42, the pressure side passages 32 and 41 of the first and second pistons 23 and 27, and the intermediate chamber 12C. A bypass path 80 is provided to allow the rod side chamber 12A and the piston side chamber 12B to communicate with each other. The extension-side back pressure chamber 61 and the compression-side back pressure chamber 71 are connected to the middle portion of the bypass passage 80. The bypass path 80 communicates with the extension-side back pressure chamber 61 by sequentially communicating a hole-like communication port 61A provided in the piston bolt 21, an inner peripheral annular groove 61B of the valve stopper 24, and a hole 61C. Further, the bypass path 80 communicates with the pressure-side back pressure chamber 71 by sequentially communicating a hole-like communication port 71A provided in the piston bolt 21, an inner peripheral annular groove 71B of the valve stopper 26, and a hole 71C.

減衰力調整装置６０は、バイパス路８０における伸側背圧室６１への連絡口６１Ａと、圧側背圧室７１への連絡口７１Ａに挟まれる中間部に可変絞り弁８１のニードル弁８１Ａを設ける。可変絞り弁８１は、ピストンロッド１３の上端部の車体側取付部１４に設けたアクチュエータ８２に連結され、ピストンロッド１３の中空部に挿通され、ピストンボルト２１のバイパス路８０の中間部に設けた弁座８０Ａに接離するニードル弁８１Ａを先端部に備える。可変絞り弁８１のニードル弁８１Ａは、アクチュエータ８２により直線移動されてバイパス路８０の弁座８０Ａに接離し、弁座８０Ａに対する絞り度を調整することにより、後述する如くに、伸側背圧室６１と圧側背圧室７１の圧力を制御し、ひいては伸側減衰バルブ３３の伸側減衰力と圧側減衰バルブ４３の圧側減衰力を調整可能にする。 The damping force adjusting device 60 is provided with a needle valve 81 A of the variable throttle valve 81 at an intermediate portion between the communication port 61 A to the extension-side back pressure chamber 61 and the communication port 71 A to the compression-side back pressure chamber 71 in the bypass passage 80. . The variable throttle valve 81 is connected to an actuator 82 provided in the vehicle body side mounting portion 14 at the upper end portion of the piston rod 13, is inserted through the hollow portion of the piston rod 13, and is provided in an intermediate portion of the bypass passage 80 of the piston bolt 21. A needle valve 81A that contacts and separates from the valve seat 80A is provided at the tip. As will be described later, the needle valve 81A of the variable throttle valve 81 is linearly moved by the actuator 82 so as to contact and separate from the valve seat 80A of the bypass passage 80 and adjust the throttle degree with respect to the valve seat 80A. 61 and the pressure in the compression-side back pressure chamber 71 are controlled, so that the expansion-side damping force of the expansion-side damping valve 33 and the compression-side damping force of the compression-side damping valve 43 can be adjusted.

従って、減衰力調整装置６０は以下の如くに動作する。
(A)可変絞り弁８１がバイパス路８０の絞り度を開き側に設定したとき Accordingly, the damping force adjusting device 60 operates as follows.
(A) When the variable throttle valve 81 sets the throttle degree of the bypass passage 80 to the open side

(A-1)伸側行程（図４（Ａ））
可変絞り弁８１が開き側にあるから、ロッド側室１２Ａの圧油がバイパス路８０をピストン側室１２Ｂに向けて素通りし易く、伸側背圧室６１の圧力は上がらない。
ロッド側室１２Ａの油が、第１のピストン２３の伸側流路３１を通り、伸側減衰バルブ３３を撓み変形させて開き、中間室１２Ｃ経由で、第２のピストン２７の伸側流路４２を通り、圧側チェック弁４４を開いてピストン側室１２Ｂに導かれ、伸側減衰力を発生させる。このとき、伸側減衰バルブ３３を閉じ方向に押さえる伸側背圧室６１の圧力が上述の如くに高くならず、伸側減衰バルブ３３は開き易くなって、伸側減衰バルブ３３の伸側減衰力は低くなる。 (A-1) Stretch side stroke (Fig. 4 (A))
Since the variable throttle valve 81 is on the open side, the pressure oil in the rod side chamber 12A easily passes through the bypass passage 80 toward the piston side chamber 12B, and the pressure in the extension side back pressure chamber 61 does not increase.
The oil in the rod side chamber 12A passes through the extension side passage 31 of the first piston 23, opens the extension side damping valve 33 by bending and deforming, and passes through the intermediate chamber 12C to the extension side passage 42 of the second piston 27. Then, the pressure side check valve 44 is opened and guided to the piston side chamber 12B to generate the extension side damping force. At this time, the pressure in the extension-side back pressure chamber 61 that presses the extension-side damping valve 33 in the closing direction does not increase as described above, and the extension-side damping valve 33 is easily opened. Power is lowered.

(A-2)圧側行程（図４（Ｂ））
可変絞り弁８１が開き側にあるから、ピストン側室１２Ｂの圧油がバイパス路８０をロッド側室１２Ａに向けて素通りし易く、圧側背圧室７１の圧力は上がらない。 (A-2) Compression side stroke (Fig. 4 (B))
Since the variable throttle valve 81 is on the open side, the pressure oil in the piston side chamber 12B easily passes through the bypass passage 80 toward the rod side chamber 12A, and the pressure in the pressure side back pressure chamber 71 does not increase.

ピストン側室１２Ｂの油が、第２のピストン２７の圧側流路４１を通り、圧側減衰バルブ４３を撓み変形させて開き、中間室１２Ｃ経由で、第１のピストン２３の圧側流路３２を通り、伸側チェック弁３４を開いてロッド側室１２Ａに導かれ、圧側減衰力を発生させる。このとき、圧側減衰バルブ４３を閉じ方向に押さえる圧側背圧室７１の圧力が上述の如くに高くならず、圧側減衰バルブ４３は開き易くなって、圧側減衰バルブ４３の圧側減衰力は低くなる。 The oil in the piston-side chamber 12B passes through the pressure-side flow path 41 of the second piston 27, bends and opens the pressure-side damping valve 43, passes through the pressure-side flow path 32 of the first piston 23 via the intermediate chamber 12C, The extension side check valve 34 is opened and guided to the rod side chamber 12A to generate a compression side damping force. At this time, the pressure in the pressure-side back pressure chamber 71 that presses the pressure-side damping valve 43 in the closing direction is not increased as described above, the pressure-side damping valve 43 is easily opened, and the pressure-side damping force of the pressure-side damping valve 43 is decreased.

(B)可変絞り弁８１がバイパス路８０の絞り度を閉じ側に設定したとき
(B-1)伸側行程（図５（Ａ））
可変絞り弁８１が閉じ側にあるから、ロッド側室１２Ａの圧油がバイパス路８０から連絡口６１Ａ等を通って伸側背圧室６１に入り、伸側背圧室６１の圧力が上がる。 (B) When the variable throttle valve 81 sets the throttle degree of the bypass passage 80 to the closed side
(B-1) Stretch side stroke (Fig. 5 (A))
Since the variable throttle valve 81 is on the closed side, the pressure oil in the rod side chamber 12A enters the extension side back pressure chamber 61 from the bypass passage 80 through the communication port 61A and the like, and the pressure in the extension side back pressure chamber 61 increases.

ロッド側室１２Ａの油が、第１のピストン２３の伸側流路３１を通り、伸側減衰バルブ３３を撓み変形させて開き、中間室１２Ｃ経由で、第２のピストン２７の伸側流路４２を通り、圧側チェック弁４４を開いてピストン側室１２Ｂに導かれ、伸側減衰力を発生させる。このとき、伸側減衰バルブ３３を閉じ方向に押さえる伸側背圧室６１の圧力が上述の如くに高くなり、伸側減衰バルブ３３は開き難くなって、伸側減衰バルブ３３の伸側減衰力は高くなる。 The oil in the rod side chamber 12A passes through the extension side passage 31 of the first piston 23, opens the extension side damping valve 33 by bending and deforming, and passes through the intermediate chamber 12C to the extension side passage 42 of the second piston 27. Then, the pressure side check valve 44 is opened and guided to the piston side chamber 12B to generate the extension side damping force. At this time, the pressure in the extension side back pressure chamber 61 that presses the extension side damping valve 33 in the closing direction becomes high as described above, and the extension side damping valve 33 becomes difficult to open, and the extension side damping force of the extension side damping valve 33 is increased. Becomes higher.

(B-2)圧側行程（図５（Ｂ））
可変絞り弁８１が閉じ側にあるから、ピストン側室１２Ｂの圧油がバイパス路８０から連絡口７１Ａを通って圧側背圧室７１に入り、圧側背圧室７１の圧力が上がる。 (B-2) Compression side stroke (Fig. 5 (B))
Since the variable throttle valve 81 is on the closed side, the pressure oil in the piston side chamber 12B enters the pressure side back pressure chamber 71 from the bypass passage 80 through the communication port 71A, and the pressure in the pressure side back pressure chamber 71 increases.

ピストン側室１２Ｂの油が、第２のピストン２７の圧側流路４１を通り、圧側減衰バルブ４３を撓み変形させて開き、中間室１２Ｃ経由で、第１のピストン２３の圧側流路３２を通り、伸側チェック弁３４を開いてロッド側室１２Ａに導かれ、圧側減衰力を発生させる。このとき、圧側減衰バルブ４３を閉じ方向に押さえる圧側背圧室７１の圧力が上述の如くに高くなり、圧側減衰バルブ４３は開き難くなって、圧側減衰バルブ４３の圧側減衰力は高くなる。 The oil in the piston-side chamber 12B passes through the pressure-side flow path 41 of the second piston 27, bends and opens the pressure-side damping valve 43, passes through the pressure-side flow path 32 of the first piston 23 via the intermediate chamber 12C, The extension side check valve 34 is opened and guided to the rod side chamber 12A to generate a compression side damping force. At this time, the pressure in the pressure-side back pressure chamber 71 that presses the pressure-side damping valve 43 in the closing direction increases as described above, the pressure-side damping valve 43 becomes difficult to open, and the pressure-side damping force of the pressure-side damping valve 43 increases.

本実施例によれば以下の作用効果を奏する。
(a)可変絞り弁８１の絞り度の調整により伸側減衰バルブ３３と圧側減衰バルブ４３を閉じ方向に押さえる伸側背圧室６１と圧側背圧室７１の圧力を制御することにより、伸側減衰力と圧側減衰力を調整できる。即ち、バイパス路８０における伸側背圧室６１への連絡口６１Ａと圧側背圧室７１への連絡口７１Ａに挟まれる中間部に可変絞り弁８１を設けたことにより、可変絞り弁８１の絞り度が開き側に設定されると伸側背圧室６１と圧側背圧室７１の圧力がともに低くなって伸側減衰力と圧側減衰力をともに低く調整できる。他方、可変絞り弁８１の絞り度が閉じ側に設定されると伸側背圧室６１と圧側背圧室７１の圧力がともに高くなって伸側減衰力と圧側減衰力をともに高く調整できる。 According to the present embodiment, the following operational effects can be obtained.
(a) By controlling the pressure of the expansion side back pressure chamber 61 and the pressure side back pressure chamber 71 that press the expansion side damping valve 33 and the compression side attenuation valve 43 in the closing direction by adjusting the throttle degree of the variable throttle valve 81, the expansion side is controlled. Damping force and compression side damping force can be adjusted. In other words, the variable throttle valve 81 is provided at the intermediate portion between the communication port 61A to the extension side back pressure chamber 61 and the communication port 71A to the compression side back pressure chamber 71 in the bypass passage 80, so that the throttle of the variable throttle valve 81 is reduced. When the degree is set to the open side, the pressures in the extension-side back pressure chamber 61 and the compression-side back pressure chamber 71 are both lowered, and both the extension-side damping force and the compression-side damping force can be adjusted to be low. On the other hand, when the throttle degree of the variable throttle valve 81 is set to the closed side, the pressures in the extension side back pressure chamber 61 and the compression side back pressure chamber 71 are both increased, and both the extension side damping force and the compression side damping force can be adjusted to be high.

(b)バイパス路８０の中間部に設けた可変絞り弁８１により伸側背圧室６１と圧側背圧室７１の圧力を制御するものであり、バイパス路８０の入口に設けた固定オリフィスにより背圧室の圧力を調整するものに比し、伸側背圧室６１と圧側背圧室７１の圧力を遅れなく制御し、伸側減衰力と圧側減衰力の調整の応答性を向上できる。 (b) The pressure in the extension-side back pressure chamber 61 and the pressure-side back pressure chamber 71 is controlled by a variable throttle valve 81 provided in the middle portion of the bypass passage 80, and the back is controlled by a fixed orifice provided at the inlet of the bypass passage 80. Compared with the one that adjusts the pressure in the pressure chamber, the pressures in the extension-side back pressure chamber 61 and the compression-side back pressure chamber 71 can be controlled without delay, and the response of adjusting the extension-side damping force and the compression-side damping force can be improved.

(c)可変絞り弁８１の絞り度の調整により伸側背圧室６１と圧側背圧室７１の圧力を制御することにより、伸側減衰バルブ３３と圧側減衰バルブ４３の開弁圧を簡易な構造により自在に制御できる。これにより、伸・圧減衰力を遅れなくスムースに、大小広い範囲に渡り、無段階に調整でき、ピストン２３、２７の微低速域から調整できる。伸側背圧室６１と圧側背圧室７１の圧力を制御することで、減衰バルブ３３、４３自体による減衰力を小さく設定でき、減衰バルブ３３、４３の開弁圧を上記圧力の制御により調整でき、伸・圧減衰力を微低速域から高速域まで無段階に調整できる。 (c) By controlling the pressure in the expansion side back pressure chamber 61 and the pressure side back pressure chamber 71 by adjusting the degree of throttling of the variable throttle valve 81, the valve opening pressure of the expansion side damping valve 33 and the pressure side damping valve 43 can be simplified. It can be freely controlled by the structure. As a result, the stretching / pressure damping force can be adjusted smoothly without delay over a wide range of large and small, and can be adjusted from the very low speed range of the pistons 23 and 27. By controlling the pressure in the extension side back pressure chamber 61 and the pressure side back pressure chamber 71, the damping force by the damping valves 33 and 43 itself can be set small, and the valve opening pressure of the damping valves 33 and 43 is adjusted by controlling the pressure. It is possible to adjust the stretching / pressure damping force steplessly from the very low speed range to the high speed range.

(d)第１と第２の２つのピストン２３、２７を設けるだけで、各ピストン２３、２７に複雑な流路等を設ける必要がないし、ピストンロッド１３に設けるバイパス路８０も唯１つで足りる。構成部品の加工工数、組立工数も多大にならず、単純になる。 (d) By only providing the first and second pistons 23 and 27, it is not necessary to provide a complicated flow path or the like for each piston 23 and 27, and there is only one bypass path 80 provided for the piston rod 13. It ’s enough. The number of processing steps and assembly steps for the component parts are not increased, and it is simplified.

(e)伸側背圧室６１と圧側背圧室７１のそれぞれが、伸側減衰バルブ３３と圧側減衰バルブ４３それぞれのためのバルブストッパ２４、２６と、それらバルブストッパ２４、２６の外周に設けたバックアップカラー６２、７２により形成され、各バックアップカラー６２、７２はスプリング６３、７３により伸側減衰バルブ３３と圧側減衰バルブ４３のそれぞれに付勢され、伸側減衰バルブ３３は伸側流路３１に臨む受圧面積を伸側背圧室６１に臨む受圧面積より大きくし、圧側減衰バルブ４３は圧側流路４１に臨む受圧面積を圧側背圧室７１に臨む受圧面積より大きくした。従って、伸側行程で、伸側流路３１と伸側背圧室６１の圧力がともに上がったとき、伸側減衰バルブ３３の上述の受圧面積の差により伸側背圧室６１の側のバックアップカラー６２が押し下げられ、このバックアップカラー６２がバックアップしている伸側減衰バルブ３３を開弁し、伸側減衰力の上限（最大減衰力）を設定できる。また、圧側行程で、圧側流路４１と圧側背圧室７１の圧力がともに上がったとき、圧側減衰バルブ４３の上述の受圧面積の差により圧側背圧室７１の側のバックアップカラー７２が押し下げられ、このバックアップカラー７２がバックアップしている圧側減衰バルブ４３を開弁し、圧側減衰力の上限（最大減衰力）を設定できる。 (e) The extension side back pressure chamber 61 and the pressure side back pressure chamber 71 are provided on the outer periphery of the valve stoppers 24 and 26 for the extension side damping valve 33 and the pressure side damping valve 43, respectively. The backup collars 62 and 72 are urged by the springs 63 and 73 to the extension side damping valve 33 and the compression side damping valve 43, respectively. The pressure receiving area that faces the expansion side back pressure chamber 61 is made larger than the pressure receiving area that faces the expansion side back pressure chamber 61, and the pressure side damping valve 43 makes the pressure receiving area that faces the pressure side flow path 41 larger than the pressure receiving area that faces the pressure side back pressure chamber 71. Therefore, when both the expansion side flow path 31 and the expansion side back pressure chamber 61 rise in the expansion side stroke, the back side of the expansion side back pressure chamber 61 is backed up by the difference in the pressure receiving area of the expansion side damping valve 33 described above. The collar 62 is pushed down, the extension side damping valve 33 backed up by the backup collar 62 is opened, and the upper limit (maximum damping force) of the extension side damping force can be set. In addition, when both the pressure in the pressure side flow path 41 and the pressure side back pressure chamber 71 rise in the pressure side stroke, the backup collar 72 on the pressure side back pressure chamber 71 side is pushed down due to the difference in the pressure receiving area of the pressure side damping valve 43 described above. The pressure side damping valve 43 backed up by the backup collar 72 is opened, and the upper limit (maximum damping force) of the pressure side damping force can be set.

以上、本発明の実施例を図面により詳述したが、本発明の具体的な構成はこの実施例に限られるものではなく、本発明の要旨を逸脱しない範囲の設計の変更等があっても本発明に含まれる。 Although the embodiments of the present invention have been described in detail with reference to the drawings, the specific configuration of the present invention is not limited to these embodiments, and even if there is a design change or the like without departing from the gist of the present invention. It is included in the present invention.

図１は減衰力調整式油圧緩衝器を示す断面図である。FIG. 1 is a cross-sectional view showing a damping force adjusting hydraulic shock absorber. 図２は図１の減衰力調整構造を示す断面図である。FIG. 2 is a cross-sectional view showing the damping force adjusting structure of FIG. 図３は図２の要部拡大図である。FIG. 3 is an enlarged view of a main part of FIG. 図４は可変絞り弁の絞り度を開き側に設定した状態で、（Ａ）は伸側行程を示す断面図、（Ｂ）は圧側行程を示す断面図である。4A and 4B show a state in which the throttle degree of the variable throttle valve is set to the open side, in which FIG. 4A is a cross-sectional view showing an extension side stroke, and FIG. 図５は可変絞り弁の絞り度を閉じ側に設定した状態で、（Ａ）は伸側減衰力を示す断面図、（Ｂ）は圧側減衰力を示す断面図である。5A and 5B are cross-sectional views showing the expansion-side damping force and FIG. 5B is a cross-sectional view showing the compression-side damping force in a state where the throttle degree of the variable throttle valve is set to the closed side.

符号の説明Explanation of symbols

１０油圧緩衝器
１２シリンダ
１２Ａロッド側室
１２Ｂピストン側室
１２Ｃ中間室
１３ピストンロッド
２３第１のピストン
２４、２６バルブストッパ
２７第２のピストン
３１伸側流路
３２圧側流路
３３伸側減衰バルブ
３４伸側チェック弁
４１圧側流路
４２伸側流路
４３圧側減衰バルブ
４４圧側チェック弁
６０減衰力調整装置
６１伸側背圧室
６１Ａ連絡口
６２バックアップカラー
６３板ばね（スプリング）
７１圧側背圧室
７１Ａ連絡口
７２バックアップカラー
７３板ばね（スプリング）
８０バイパス路
８１可変絞り弁 DESCRIPTION OF SYMBOLS 10 Hydraulic buffer 12 Cylinder 12A Rod side chamber 12B Piston side chamber 12C Intermediate chamber 13 Piston rod 23 First piston 24, 26 Valve stopper 27 Second piston 31 Stretch side flow path 32 Pressure side flow path 33 Stretch side damping valve 34 Stretch side Check valve 41 Pressure side flow path 42 Extension side flow path 43 Pressure side damping valve 44 Pressure side check valve 60 Damping force adjustment device 61 Extension side back pressure chamber 61A Contact port 62 Backup collar 63 Leaf spring (spring)
71 Pressure side back pressure chamber 71A Communication port 72 Backup collar 73 Leaf spring
80 Bypass 81 Variable throttle valve

Claims

シリンダにピストンロッドを挿入し、
ピストンロッドに第１と第２のピストンを固定し、
シリンダの内部に、第１のピストンと第２のピストンに挟まれる中間室と、第１のピストンの中間室に対する反対側に区画されるロッド側室と、第２のピストンの中間室に対する反対側に区画されるピストン側室を設け、
第１のピストンはロッド側室と中間室を連通可能にする伸側流路と圧側流路を備えるとともに、伸側流路を伸側行程で開く伸側減衰バルブと、圧側流路を伸側行程では閉じ、圧側行程で開く伸側チェック弁を有し、
第２のピストンはピストン側室と中間室を連通可能にする圧側流路と伸側流路を備えるとともに、圧側流路を圧側行程で開く圧側減衰バルブと、伸側流路を圧側行程では閉じ、伸側行程では開く圧側チェック弁を有してなる減衰力調整式油圧緩衝器であって、
第１のピストンにおける伸側減衰バルブの伸側流路に対する背面側と、第２のピストンにおける圧側減衰バルブの圧側流路に対する背面側のそれぞれに、伸側背圧室と圧側背圧室のそれぞれを設け、
ピストンロッドに第１と第２の両ピストンの伸側流路と圧側流路を迂回してロッド側室とピストン側室を連絡するバイパス路を設け、
バイパス路の中間部に伸側背圧室と圧側背圧室を連絡し、
バイパス路における伸側背圧室への連絡口と圧側背圧室への連絡口に挟まれる中間部に可変絞り弁を設け、
可変絞り弁の絞り度の調整により伸側背圧室と圧側背圧室の圧力を制御することにより、伸側減衰力と圧側減衰力を調整可能にすることを特徴とする減衰力調整式油圧緩衝器。 Insert the piston rod into the cylinder,
First and second pistons are fixed to the piston rod,
Inside the cylinder, an intermediate chamber sandwiched between the first piston and the second piston, a rod side chamber defined on the opposite side of the first piston to the intermediate chamber, and an opposite side of the second piston to the intermediate chamber A piston side chamber is provided,
The first piston includes an extension side flow path and a pressure side flow path that allow the rod side chamber and the intermediate chamber to communicate with each other, an extension side damping valve that opens the extension side flow path in the extension side stroke, and a pressure side flow path in the extension side stroke Has an extension check valve that closes and opens in the compression stroke,
The second piston includes a pressure side flow path and an extension side flow path that allow the piston side chamber and the intermediate chamber to communicate with each other, a pressure side damping valve that opens the pressure side flow path in the pressure side stroke, and the extension side flow path is closed in the pressure side stroke. A damping force adjustment type hydraulic shock absorber having a pressure side check valve that opens in the extension side stroke,
Each of an extension-side back pressure chamber and a compression-side back pressure chamber is provided on each of the back side of the extension side damping valve of the first piston with respect to the extension side flow path and the back side of the compression side attenuation valve of the second piston. Provided,
A bypass path is provided in the piston rod to bypass the extension side flow path and the pressure side flow path of both the first and second pistons and connect the rod side chamber and the piston side chamber,
The extension side pressure chamber and the compression side back pressure chamber are connected to the middle part of the bypass passage,
A variable throttle valve is provided in the middle part between the communication port to the extension side back pressure chamber and the communication port to the compression side back pressure chamber in the bypass passage,
Damping force adjustable hydraulic, characterized in that the expansion side compression force and the compression side damping force can be adjusted by controlling the pressure in the expansion side back pressure chamber and the compression side back pressure chamber by adjusting the throttle degree of the variable throttle valve Shock absorber.

前記伸側背圧室と圧側背圧室のそれぞれが、伸側減衰バルブと圧側減衰バルブそれぞれのためのバルブストッパと、それらバルブストッパの外周に設けたバックアップカラーにより形成され、各バックアップカラーはスプリングにより伸側減衰バルブと圧側減衰バルブのそれぞれに付勢され、
伸側減衰バルブは伸側流路に臨む受圧面積を伸側背圧室に臨む受圧面積より大きくし、
圧側減衰バルブは圧側流路に臨む受圧面積を圧側背圧室に臨む受圧面積より大きくしてなる請求項１に記載の減衰力調整式油圧緩衝器。 Each of the extension-side back pressure chamber and the compression-side back pressure chamber is formed by a valve stopper for each of the extension-side damping valve and the compression-side damping valve, and a backup collar provided on the outer periphery of the valve stopper, and each backup collar is a spring. Is applied to each of the expansion side damping valve and the compression side damping valve,
The expansion side damping valve makes the pressure receiving area facing the expansion side flow path larger than the pressure receiving area facing the expansion side back pressure chamber,
The damping force adjusting hydraulic shock absorber according to claim 1, wherein the pressure side damping valve has a pressure receiving area facing the pressure side flow path larger than a pressure receiving area facing the pressure side back pressure chamber.