JP2009204118A - Hydraulic shock absorber - Google Patents

Hydraulic shock absorber

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JP2009204118A
JP2009204118A JP2008048420A JP2008048420A JP2009204118A JP 2009204118 A JP2009204118 A JP 2009204118A JP 2008048420 A JP2008048420 A JP 2008048420A JP 2008048420 A JP2008048420 A JP 2008048420A JP 2009204118 A JP2009204118 A JP 2009204118A
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oil chamber
chamber
inner tube
cylinder
piston
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Japanese (ja)
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Osamu Nagai
修 永井
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Showa Corp
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Showa Corp
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Abstract

<P>PROBLEM TO BE SOLVED: To prevent the breakage in the elongation stroke of a seal material which seals an annular oil chamber, in an opening portion on the inner periphery of an outer tube. <P>SOLUTION: In this hydraulic shock absorber 10, an outside operating oil chamber 20 in an inner tube 12 is communicated with a piston rod side oil chamber 21A in a cylinder 18 via an upper throttle hole 27, and the outside operating oil chamber 20 in the inner tube 12 is communicated with a piston side oil chamber 21B in the cylinder 18 via a lower throttle hole 28. In the elongation stroke, the upper throttle hole 27 is more strongly throttled than the lower throttle hole 28. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

本発明は車両用の油圧緩衝器に関する。   The present invention relates to a hydraulic shock absorber for a vehicle.

フロントフォーク等の油圧緩衝器として、特許文献１に記載の如く、アウタチューブの内周の開口部と、インナチューブの外周の先端部のそれぞれに固定したブッシュを介して、アウタチューブ内にインナチューブを摺動自在に挿入し、該アウタチューブの内周と、インナチューブの外周と、前記２つのブッシュとで囲まれる環状の油室を区画し、前記インナチューブの内周に隔壁部材を設け、下部に油室を区画するとともに、上部に油溜室を区画し、前記アウタチューブに取付けたピストンロッドを該隔壁部材に摺動自在に挿入し、前記インナチューブに挿入したピストンロッドの先端部に該インナチューブ内に摺動するピストンを固定し、前記油室を前記ピストンロッドが収容されるピストンロッド側油室と前記ピストンロッドが収容されないピストン側油室に区画し、前記環状の油室を前記インナチューブに設けた連通孔を介して前記ピストンロッド側油室に連通した車両用の油圧緩衝器において、前記環状の油室の断面積を前記ピストンロッドの断面積より大きく形成し、かつ、前記隔壁部材に伸側行程時に前記油室から前記油溜室内への流れを阻止するチェック弁を設けるとともに、前記隔壁部材に前記油室と前記油溜室を通過する体積補償用絞り流路を設けたものがある。   As a hydraulic shock absorber such as a front fork, as described in Patent Document 1, the inner tube is inserted into the outer tube through bushes fixed to the inner peripheral opening of the outer tube and the outer peripheral tip of the inner tube. And an annular oil chamber surrounded by the inner periphery of the outer tube, the outer periphery of the inner tube, and the two bushes, and a partition member provided on the inner periphery of the inner tube, An oil chamber is defined in the lower portion, an oil reservoir chamber is defined in the upper portion, a piston rod attached to the outer tube is slidably inserted into the partition member, and the piston rod inserted into the inner tube is inserted at the tip of the piston rod. A piston that slides in the inner tube is fixed, and the oil chamber accommodates the piston rod side oil chamber in which the piston rod is accommodated and the piston rod. In a hydraulic shock absorber for a vehicle, which is partitioned into a piston-side oil chamber, and the annular oil chamber communicates with the piston rod-side oil chamber via a communication hole provided in the inner tube. The partition member is provided with a check valve for preventing the flow from the oil chamber to the oil reservoir chamber during the extension stroke, and the partition member is provided with the oil chamber. And a volume compensating throttle channel that passes through the oil reservoir.

この従来の油圧緩衝器では、圧側行程でインナチューブに進入するピストンロッドの進入容積分の作動油がインナチューブ内のピストンロッド側油室からインナチューブの連通孔を通って環状油室に補給される。このとき、環状油室の容積増加分ΔＳ1（補給量）がピストンロッドの容積増加分ΔＳ2より大きいから、環状油室への油の必要補給量のうち、（ΔＳ1−ΔＳ2）の不足分が油溜室からチェック弁経由でピストンロッド側油室を介して補給される。   In this conventional hydraulic shock absorber, hydraulic oil corresponding to the volume of the piston rod that enters the inner tube in the compression stroke is supplied from the piston rod side oil chamber in the inner tube to the annular oil chamber through the inner tube communication hole. The At this time, since the volume increase ΔS1 (replenishment amount) of the annular oil chamber is larger than the volume increase ΔS2 of the piston rod, the shortage of (ΔS1−ΔS2) of the required oil replenishment amount to the annular oil chamber is oil. Replenishment from the reservoir chamber via the check valve via the piston rod side oil chamber.

また、伸側行程でインナチューブから退出するピストンロッドの退出容積分の作動油が環状油室からインナチューブの連通孔を通ってインナチューブ内のピストンロッド側油室に排出される。このとき、環状油室の容積減少分ΔＳ1（排出量）がピストンロッドの容積減少分ΔＳ2より大きいから、環状油室からの油の排出量のうち、（ΔＳ1−ΔＳ2）の余剰分がピストンロッド側油室経由で体積補償用絞り流路を通って油溜室へ排出される。この伸側行程では、体積補償用絞り流路の通路抵抗が伸側減衰力を発生させるものになる。
特開2003-269515 Further, the hydraulic oil corresponding to the retracted volume of the piston rod that retreats from the inner tube in the extension stroke is discharged from the annular oil chamber to the piston rod side oil chamber in the inner tube through the communication hole of the inner tube. At this time, since the volume decrease ΔS1 (discharge amount) of the annular oil chamber is larger than the volume decrease ΔS2 of the piston rod, the excess amount (ΔS1−ΔS2) of the oil discharge amount from the annular oil chamber is the piston rod. It is discharged to the oil reservoir chamber through the volume compensation throttle channel via the side oil chamber. In this extension side stroke, the passage resistance of the volume compensating throttle channel generates the extension side damping force.
JP2003-269515

特許文献１に記載の油圧緩衝器には以下の問題点がある。
伸側行程では、環状油室内の油が上述の如くに排出されるから、環状油室の圧力は正圧になる。加えて、伸側行程では、環状油室の油の余剰分がピストンロッド側油室経由で体積補償用絞り流路を通り、その間の体積補償用絞り流路の通路抵抗が伸側減衰力を発生させる。従って、伸側減衰力を発生させる体積補償用絞り流路の通路抵抗が背圧となるピストンロッド側油室の圧力は、伸側減衰力を高く設定して高圧になるとき、インナチューブの連通孔を介して環状油室、ひいてはアウタチューブの内周の開口部で環状油室をシールするシール材に及び、このシール材を破損させるおそれがある。従って、この仕様の油圧緩衝器は、オフロード系車両において、高ピストン速度に起因して高減衰力を発生させる使用条件では採用できない。 The hydraulic shock absorber described in Patent Document 1 has the following problems.
In the extension stroke, the oil in the annular oil chamber is discharged as described above, so the pressure in the annular oil chamber becomes positive. In addition, in the extension stroke, the excess oil in the annular oil chamber passes through the volume compensation throttle passage via the piston rod side oil chamber, and the passage resistance of the volume compensation throttle passage in the meantime increases the extension damping force. generate. Therefore, when the pressure in the piston rod side oil chamber, where the passage resistance of the volume compensation throttle channel that generates the expansion side damping force becomes the back pressure, is set to a high value by setting the expansion side damping force high, the inner tube communication There is a risk of damaging the sealing material that seals the annular oil chamber through the hole and thus the annular oil chamber at the inner peripheral opening of the outer tube. Therefore, the hydraulic shock absorber of this specification cannot be employed in an off-road vehicle under use conditions that generate a high damping force due to a high piston speed.

尚、圧側行程では、環状油室内に油が補給され、環状油室の圧力は負圧になるから、この環状油室をシールするシール材が破損するおそれはない。   In the pressure side stroke, oil is replenished in the annular oil chamber and the pressure in the annular oil chamber becomes negative. Therefore, there is no possibility that the sealing material for sealing the annular oil chamber is damaged.

本発明の課題は、アウタチューブ内にインナチューブを摺動自在に挿入し、アウタチューブの内周とインナチューブの外周との間に区画した環状油室をインナチューブに設けた連通孔を介してインナチューブ内の作動油室に連通する油圧緩衝器において、アウタチューブの内周の開口部で環状油室をシールするシール材の伸側行程における破損を防止することにある。   An object of the present invention is to insert an inner tube slidably into an outer tube, and through a communication hole provided in the inner tube with an annular oil chamber defined between the inner periphery of the outer tube and the outer periphery of the inner tube. In the hydraulic shock absorber communicating with the hydraulic oil chamber in the inner tube, it is intended to prevent breakage of the sealing material for sealing the annular oil chamber at the inner peripheral opening of the outer tube in the extension side stroke.

請求項１の発明は、車体側のアウタチューブ内に車軸側のインナチューブを摺動自在に挿入し、インナチューブの内部にシリンダを立設し、インナチューブとシリンダの上部に隔壁部材を設け、隔壁部材の下部のインナチューブとシリンダの間に外側作動油室を、シリンダの内部に内側作動油室をそれぞれ区画するとともに、隔壁部材の上部に油溜室を区画し、アウタチューブ側に取付けたピストン支持部材を、隔壁部材に通してシリンダ内の内側作動油室に挿入し、ピストン支持部材の先端部にシリンダ内を摺動するピストンを設け、シリンダ内の内側作動油室をピストンロッドが収容されるピストンロッド側油室と、ピストンロッドが収容されないピストン側油室に区画し、インナチューブ内の外側作動油室と、シリンダ内のピストンロッド側油室を上絞り孔により連通するとともに、インナチューブ内の外側作動油室と、シリンダ内のピストン側油室を下絞り孔により連通し、伸側行程で上絞り孔を下絞り孔より強く絞り、アウタチューブの内周とインナチューブの外周との間に環状油室を区画し、この環状油室をインナチューブに設けた連通孔を介してインナチューブ内の外側作動油室に連通し、環状油室の断面積をピストン支持部材の断面積より大きく形成し、ピストン支持部材が内側作動油室から退出する伸側行程で内側作動油室又は外側作動油室の油を油溜室へ流す体積補償用絞り流路と、伸側行程で内側作動油室又は外側作動油室から油溜室への油の流れを阻止するチェック弁とを有してなるようにしたものである。   In the first aspect of the invention, the inner tube on the axle side is slidably inserted into the outer tube on the vehicle body side, a cylinder is erected inside the inner tube, and a partition member is provided on the inner tube and the upper portion of the cylinder, An outer hydraulic oil chamber is defined between the inner tube and the cylinder at the lower part of the partition member, an inner hydraulic oil chamber is defined inside the cylinder, and an oil reservoir chamber is defined at the upper part of the partition member, and is attached to the outer tube side. The piston support member is inserted into the inner hydraulic oil chamber in the cylinder through the partition member, and a piston that slides in the cylinder is provided at the tip of the piston support member, and the piston rod accommodates the inner hydraulic oil chamber in the cylinder. Divided into a piston rod side oil chamber and a piston side oil chamber in which the piston rod is not accommodated, and an outer hydraulic oil chamber in the inner tube and a piston rod in the cylinder. The upper side oil chamber communicates with the upper throttle hole, and the outer hydraulic oil chamber in the inner tube and the piston side oil chamber in the cylinder communicate with each other through the lower throttle hole. The annular oil chamber is partitioned between the inner periphery of the outer tube and the outer periphery of the inner tube, and this annular oil chamber communicates with the outer hydraulic oil chamber in the inner tube through a communication hole provided in the inner tube. The cross-sectional area of the annular oil chamber is formed larger than the cross-sectional area of the piston support member, and the oil in the inner hydraulic oil chamber or the outer hydraulic oil chamber is transferred to the oil reservoir chamber in the extension side stroke in which the piston support member retreats from the inner hydraulic oil chamber. It has a throttle channel for volume compensation to flow and a check valve for preventing the flow of oil from the inner hydraulic oil chamber or the outer hydraulic oil chamber to the oil reservoir chamber in the extension stroke.

請求項２の発明は、請求項１の発明において更に、前記伸側行程の外側作動油室の一定圧力以上の油を油溜室へ逃がすブロー弁を設けたものである。   According to a second aspect of the present invention, in the first aspect of the present invention, a blow valve is provided for releasing oil having a pressure equal to or higher than that of the outer hydraulic oil chamber in the extension stroke to the oil reservoir chamber.

（請求項１）
(a)伸側行程で、環状油室に連通している外側作動油室の圧力を以下の理由で上げることがないから、外側作動油室の高圧油が環状油室に及んで、アウタチューブの内周の開口部で環状油室をシールしているシール材を破損することがない。 (Claim 1)
(a) In the extension stroke, the pressure of the outer hydraulic oil chamber communicating with the annular oil chamber is not increased for the following reason, so that the high pressure oil in the outer hydraulic oil chamber reaches the annular oil chamber, and the outer tube The sealing material that seals the annular oil chamber at the opening on the inner circumference of the inner ring is not damaged.

(a-1)下絞り孔を設けたことで、ピストンロッドの退出容積補償の油を外側作動油室から下絞り孔を介してピストン側油室に補給できる。これにより、外側作動油室の圧力を低くすることができる。尚、下絞り孔がない場合は、外側作動油室の油を上絞り孔から伸側行程の故に高圧になっているピストンロッド側油室経由でピストン側油室に補給する必要があり、外側作動油室の圧力は高圧のピストンロッド側油室と同等以上でなければならなくなる。   (a-1) By providing the lower throttle hole, the piston rod withdrawal volume compensation oil can be supplied from the outer hydraulic oil chamber to the piston-side oil chamber through the lower throttle hole. Thereby, the pressure of an outer side hydraulic oil chamber can be made low. If there is no lower throttle hole, the oil in the outer hydraulic oil chamber must be replenished from the upper throttle hole to the piston side oil chamber via the piston rod side oil chamber that is at a high pressure due to the extension stroke. The pressure in the hydraulic oil chamber must be equal to or higher than that of the high pressure piston rod side oil chamber.

(a-2)下絞り孔を設けたことで、ピストンロッドの退出容積補償の油を外側作動油室から下絞り孔を介してピストン側油室に補給できる。これにより、上絞り孔をピストンロッドの退出容積補償の油の流路とする必要がなくなって絞ることができるようになるから、減衰力発生装置を高減衰に設定しても、伸側減衰発生時にピストンロッド側油室の高圧が直接外側作動油室にかかることがなくなり、外側作動油室の圧力が上がらない。   (a-2) By providing the lower throttle hole, the piston rod withdrawal volume compensation oil can be supplied from the outer hydraulic oil chamber to the piston-side oil chamber through the lower throttle hole. This eliminates the need for the upper throttle hole as an oil flow path for the piston rod withdrawal volume compensation, so that the throttle can be throttled. Sometimes, the high pressure of the piston rod side oil chamber is not directly applied to the outer hydraulic oil chamber, and the pressure of the outer hydraulic oil chamber does not increase.

(a-3)上絞り孔を下絞り孔より強く絞ったから、ピストンロッドの退出容積補償の油を外側作動油室から下絞り孔を介してピストン側油室に補給するとき、外側作動油室の圧力が上がらない。   (a-3) Since the upper throttle hole is squeezed more strongly than the lower throttle hole, when the piston rod withdrawal volume compensation oil is supplied from the outer hydraulic oil chamber to the piston side oil chamber via the lower throttle hole, the outer hydraulic oil chamber The pressure does not increase.

(a-4)環状油室の油の余剰分が外側作動油室経由で体積補償用絞り流路から油溜室へ排出されるとき、必要以上の油が排出しないように体積補償用絞り流路を絞っているが、外側作動油室の圧力が下がれば、相対的に体積補償用絞り流路での設定減衰力も下がり、結果として外側作動油室の圧力が上がらない。   (a-4) When the excess oil in the annular oil chamber is discharged from the volume compensation throttle passage to the oil reservoir chamber via the outer hydraulic oil chamber, the volume compensation throttle flow is prevented so that excessive oil is not discharged. If the pressure in the outer hydraulic oil chamber is reduced, the set damping force in the volume compensation throttle passage is also relatively lowered, and as a result, the pressure in the outer hydraulic oil chamber is not increased.

尚、圧側行程では、環状油室内に油が補給され、環状油室の圧力は負圧になるから、この環状油室をシールするシール材が破損するおそれはない。   In the pressure side stroke, oil is replenished in the annular oil chamber and the pressure in the annular oil chamber becomes negative. Therefore, there is no possibility that the sealing material for sealing the annular oil chamber is damaged.

（請求項２）
(b)体積補償用絞り流路が外側作動油室の油を油溜室へ流すように設けられ、伸側行程の高ピストン速度に起因して外側作動油室の油の圧力が一定圧力以上に上昇するときには、直ちにブロー弁が開き、この外側作動油室の油を油溜室へ逃がす。これにより、高圧の外側作動油室の油がインナチューブの連通孔を介して環状油室に及ぶことがない。 (Claim 2)
(b) A volume compensation throttle passage is provided so that the oil in the outer hydraulic oil chamber flows into the oil reservoir chamber, and the oil pressure in the outer hydraulic oil chamber exceeds a certain pressure due to the high piston speed in the extension side stroke. When the air pressure rises, the blow valve immediately opens, and the oil in the outer hydraulic oil chamber is released to the oil reservoir chamber. Thus, the oil in the high-pressure outer hydraulic oil chamber does not reach the annular oil chamber via the inner tube communication hole.

図１は油圧緩衝器の全体を示す断面図、図２は図１の下部拡大断面図、図３は図１の中間部拡大断面図、図４は図１の上部拡大断面図、図５は図３の要部拡大断面図である。   1 is a cross-sectional view showing the entire hydraulic shock absorber, FIG. 2 is a lower enlarged cross-sectional view of FIG. 1, FIG. 3 is an enlarged intermediate cross-sectional view of FIG. 1, FIG. It is a principal part expanded sectional view of FIG.

フロントフォーク（油圧緩衝器）１０は、アウタチューブ１１を車体側に、インナチューブ１２を車輪側に配置する倒立型フロントフォークであり、図１〜図４に示す如く、アウタチューブ１１の下端開口部の内周に固定したガイドブッシュ１１Ａと、インナチューブ１２の上端開口部の外周に固定したガイドブッシュ１２Ａ（インナチューブ１２の内周であってガイドブッシュ１２Ａの下部にはシール部材１２Ｂを付帯的に備える）を介して、アウタチューブ１１の内部にインナチューブ１２を摺動自在に挿入する。１１Ｂはオイルシール、１１Ｃはダストシールである。アウタチューブ１１の上端開口部にはキャップ１３が液密に螺着され、アウタチューブ１１の外周には車体側取付部材が設けられる。インナチューブ１２の下端開口部にはボトムピース１４、車軸ブラケット１５が液密に挿着されてインナチューブ１２の底部を構成し、車軸ブラケット１５には車軸取付孔１６が設けられる。このとき、インナチューブ１２の底部を形成するボトムピース１４が有底筒状をなして車軸ブラケット１５の内径段差部に装填されるとともに、インナチューブ１２の下端部が車軸ブラケット１５の内径に螺着され、インナチューブ１２の下端面がボトムピース１４の外周段差部を車軸ブラケット１５の内径段差部との間に挟圧保持する。   The front fork (hydraulic shock absorber) 10 is an inverted front fork in which the outer tube 11 is disposed on the vehicle body side and the inner tube 12 is disposed on the wheel side. As shown in FIGS. The guide bush 11A fixed to the inner periphery of the inner tube 12 and the guide bush 12A fixed to the outer periphery of the upper end opening of the inner tube 12 (the seal member 12B is attached to the lower portion of the guide bush 12A on the inner periphery of the inner tube 12) The inner tube 12 is slidably inserted into the outer tube 11. 11B is an oil seal, and 11C is a dust seal. A cap 13 is screwed in a liquid-tight manner to the upper end opening of the outer tube 11, and a vehicle body side mounting member is provided on the outer periphery of the outer tube 11. A bottom piece 14 and an axle bracket 15 are liquid-tightly inserted into the lower end opening of the inner tube 12 to form the bottom of the inner tube 12, and an axle mounting hole 16 is provided in the axle bracket 15. At this time, the bottom piece 14 that forms the bottom of the inner tube 12 forms a bottomed cylindrical shape and is loaded into the inner diameter step portion of the axle bracket 15, and the lower end portion of the inner tube 12 is screwed to the inner diameter of the axle bracket 15. The lower end surface of the inner tube 12 holds the outer circumferential step portion of the bottom piece 14 between the inner diameter step portion of the axle bracket 15 and holds it.

フロントフォーク１０は、アウタチューブ１１の内周と、インナチューブ１２の外周と、前記２つのガイドブッシュ１１Ａ、１２Ａにて区画される環状油室１７を区画する。   The front fork 10 defines an annular oil chamber 17 defined by the inner periphery of the outer tube 11, the outer periphery of the inner tube 12, and the two guide bushes 11A and 12A.

フロントフォーク１０は、インナチューブ１２の内部にシリンダ１８を立設する。シリンダ１８の下端部はボトムピース１４の内周に螺着されてボトムピース１４の底面と衝合し、インナチューブ１２と環状間隙を介する状態で該インナチューブ１２と同軸配置される。   The front fork 10 erects a cylinder 18 inside the inner tube 12. The lower end portion of the cylinder 18 is screwed to the inner periphery of the bottom piece 14 and abuts with the bottom surface of the bottom piece 14, and is coaxially arranged with the inner tube 12 through an annular gap with the inner tube 12.

フロントフォーク１０は、インナチューブ１２とシリンダ１８の上部に隔壁部材１９を設ける。隔壁部材１９はシリンダ１８の上端外周に螺着される。隔壁部材１９の上端面側には後述するバルブ押え６７が設置され、バルブ押え６７の外周に装填したシール部材６８がインナチューブ１２の上端側の内周に液密に挿着されている。   The front fork 10 is provided with a partition member 19 on the inner tube 12 and the cylinder 18. The partition member 19 is screwed to the outer periphery of the upper end of the cylinder 18. A valve presser 67 which will be described later is installed on the upper end surface side of the partition wall member 19, and a seal member 68 loaded on the outer periphery of the valve presser 67 is inserted in a liquid-tight manner on the inner periphery on the upper end side of the inner tube 12.

フロントフォーク１０は、隔壁部材１９の下部のインナチューブ１２とシリンダ１８の間に外側作動油室２０を、シリンダ１８の内部に内側作動油室２１をそれぞれ区画するとともに、隔壁部材１９の上部に油溜室２２を区画する。油溜室２２の中でその下側領域は油室２２Ａ（油面Ｌ）、上側領域は空気室２２Ｂである。   The front fork 10 partitions an outer hydraulic oil chamber 20 between the inner tube 12 below the partition wall member 19 and the cylinder 18, an inner hydraulic oil chamber 21 inside the cylinder 18, and oil above the partition wall member 19. The reservoir chamber 22 is partitioned. In the oil reservoir chamber 22, the lower region is an oil chamber 22A (oil surface L), and the upper region is an air chamber 22B.

フロントフォーク１０は、図５に示す如く、アウタチューブ１１に取付けたピストンロッド２３を隔壁部材１９に通してシリンダ１８内の内側作動油室２１に挿入する。具体的には、キャップ１３の中心部の下端部にピストンロッド２３を螺着し、これをロックナット２４で固定する。   As shown in FIG. 5, the front fork 10 inserts the piston rod 23 attached to the outer tube 11 through the partition member 19 into the inner hydraulic oil chamber 21 in the cylinder 18. Specifically, a piston rod 23 is screwed to the lower end portion of the center portion of the cap 13 and fixed with a lock nut 24.

フロントフォーク１０は、隔壁部材１９からシリンダ１８に挿入したピストンロッド２３の先端部に螺着したピストンボルト２５に、シリンダ１８の内周に摺動するピストン２６を固定し、前記内側作動油室２１をピストンロッド２３が収容されるピストンロッド側油室２１Ａと、ピストンロッド２３が収容されないピストン側油室２１Ｂに区画する。ピストン２６はピストンナット２５Ａにより固定される。   In the front fork 10, a piston 26 that slides on the inner periphery of the cylinder 18 is fixed to a piston bolt 25 that is screwed onto the tip of a piston rod 23 that is inserted into the cylinder 18 from the partition wall member 19. Are divided into a piston rod side oil chamber 21A in which the piston rod 23 is accommodated and a piston side oil chamber 21B in which the piston rod 23 is not accommodated. The piston 26 is fixed by a piston nut 25A.

フロントフォーク１０は、インナチューブ１２内の外側作動油室２０と、シリンダ１８内の内側作動油室２１のピストンロッド側油室２１Ａを、シリンダ１８に設けた上絞り孔２７により常時連通する。また、インナチューブ１２内の外側作動油室２０と、シリンダ１８内の内側作動油室２１のピストン側油室２１Ｂを、シリンダ１８に設けた下絞り孔２８により常時連通する。上絞り孔２７を下絞り孔２８より強く絞る。   The front fork 10 always communicates the outer hydraulic oil chamber 20 in the inner tube 12 and the piston rod side oil chamber 21 </ b> A of the inner hydraulic oil chamber 21 in the cylinder 18 through an upper throttle hole 27 provided in the cylinder 18. Further, the outer hydraulic oil chamber 20 in the inner tube 12 and the piston-side oil chamber 21 </ b> B of the inner hydraulic oil chamber 21 in the cylinder 18 are always in communication with each other through a lower throttle hole 28 provided in the cylinder 18. The upper throttle hole 27 is squeezed more strongly than the lower throttle hole 28.

フロントフォーク１０は、前記環状油室１７を、インナチューブ１２に設けた連通孔２９を介してインナチューブ１２内の外側作動油室２０に常時連通する。   The front fork 10 always communicates the annular oil chamber 17 with the outer hydraulic oil chamber 20 in the inner tube 12 through a communication hole 29 provided in the inner tube 12.

フロントフォーク１０は、アウタチューブ１１の上端開口部に設けたキャップ１３の下端面と、インナチューブ１２とシリンダ１８の上部に設けた隔壁部材１９の上のバルブ押え６７の上端面との間に、懸架スプリング３０を介装している。ピストンロッド２３の上端側外周には、懸架スプリング３０の内周をガイドするスプリングガイド３１が設けられている。フロントフォーク１０は、車両走行時に路面から受ける衝撃力を懸架スプリング３０の伸縮振動により吸収する。   The front fork 10 is located between the lower end surface of the cap 13 provided at the upper end opening of the outer tube 11 and the upper end surface of the valve presser 67 on the inner tube 12 and the partition member 19 provided on the upper portion of the cylinder 18. A suspension spring 30 is interposed. A spring guide 31 for guiding the inner periphery of the suspension spring 30 is provided on the outer periphery on the upper end side of the piston rod 23. The front fork 10 absorbs the impact force received from the road surface when the vehicle travels by the expansion and contraction vibration of the suspension spring 30.

フロントフォーク１０は、ピストン２６に減衰力発生装置４０を備える（図３）。
減衰力発生装置４０は、圧側流路４１と伸側流路４２を備える。圧側流路４１は、バルブストッパ４１Ｂにバックアップされる圧側ディスクバルブ４１Ａ（圧側減衰バルブ）により開閉される。伸側流路４２は、バルブストッパ４２Ｂにバックアップされる伸側ディスクバルブ４２Ａ（伸側減衰バルブ）により開閉される。尚、バルブストッパ４１Ｂ、バルブ４１Ａ、ピストン２６、バルブ４２Ａ、バルブストッパ４２Ｂは、ピストンボルト２５に挿着されるバルブ組立体を構成し、ピストンボルト２５に螺着されるピストンナット２５Ａに挟まれて固定される。 The front fork 10 includes a damping force generator 40 on the piston 26 (FIG. 3).
The damping force generator 40 includes a compression side channel 41 and an extension side channel 42. The pressure side channel 41 is opened and closed by a pressure side disk valve 41A (pressure side damping valve) backed up by a valve stopper 41B. The extension side flow path 42 is opened and closed by an extension side disk valve 42A (extension side damping valve) backed up by a valve stopper 42B. The valve stopper 41B, the valve 41A, the piston 26, the valve 42A, and the valve stopper 42B constitute a valve assembly that is inserted into the piston bolt 25, and are sandwiched between piston nuts 25A that are screwed into the piston bolt 25. Fixed.

減衰力発生装置４０は、圧側行程では、圧側ディスクバルブ４１Ａの撓み変形により圧側減衰力を発生する。また、伸側行程では、伸側ディスクバルブ４２Ａの撓み変形により伸側減衰力を発生する。この圧側減衰力と伸側減衰力により、前述した懸架スプリング３０の伸縮振動を制振する。   The damping force generating device 40 generates a compression side damping force by the bending deformation of the compression side disk valve 41A in the compression side stroke. In the extension side stroke, the extension side damping force is generated by the bending deformation of the extension side disk valve 42A. The compression-side damping force and the extension-side damping force suppress the expansion and contraction vibration of the suspension spring 30 described above.

フロントフォーク１０は、ピストンボルト２５の上端面とシリンダ１８の上端側の隔壁部材１９のピストンロッド側油室２１Ａに臨む下端面に設けたスプリングシート５１との間にリバウンドスプリング５２を介装している。フロントフォーク１０の最伸長時に、ピストンボルト２５の上端面とスプリングシート５１の間でリバウンドスプリング５２を加圧することにより、最伸長ストロークを規制する。   The front fork 10 has a rebound spring 52 interposed between an upper end surface of the piston bolt 25 and a spring seat 51 provided on a lower end surface of the partition wall member 19 on the upper end side of the cylinder 18 facing the piston rod side oil chamber 21A. Yes. When the front fork 10 is fully extended, the maximum extension stroke is regulated by pressurizing the rebound spring 52 between the upper end surface of the piston bolt 25 and the spring seat 51.

しかるに、フロントフォーク１０にあっては、アウタチューブ１１とインナチューブ１２の環状隙間からなる前記環状油室１７の断面積Ｓ1を、ピストンロッド２３の断面積（外径に囲まれる面積）Ｓ2より大きく形成している（Ｓ1＞Ｓ2、但しＳ1≧Ｓ2でも可）。   However, in the front fork 10, the sectional area S1 of the annular oil chamber 17 formed by the annular gap between the outer tube 11 and the inner tube 12 is larger than the sectional area (area surrounded by the outer diameter) S2 of the piston rod 23. (S1> S2, where S1 ≧ S2 is acceptable).

また、隔壁部材１９に、圧側行程では油溜室２２からピストンロッド側油室２１Ａへの油の流れを許容し、伸側行程ではピストンロッド側油室２１Ａから油溜室２２への油の流れを阻止するチェック弁６０を設けている。隔壁部材１９とスプリングシート５１の内周にはバルブ室６１が設けられ、バルブ室６１の上端側の段差部６１Ａと、バルブ室６１の下端側のスプリングシート５１上のバックアップスプリング６２との間にチェック弁６０のフランジ６０Ａが収容される。チェック弁６０のフランジ６０Ａは、段差部６１Ａとスプリングシート５１の間隔より短尺とされ、下端面に横溝を形成される。チェック弁６０のフランジ６０Ａは、バルブ室６１の内周を上下変位可能に設けられる。チェック弁６０のフランジ６０Ａの外周は、バルブ室６１の内周との間に、油溜室２２からピストンロッド側油室２１Ａへの油の流れを許容する流路を形成する。チェック弁６０は、ピストンロッド２３を摺動自在に支持するブッシュ６３をその内周に圧入されて備える。圧側行程では、チェック弁６０はシリンダ１８に進入するピストンロッド２３に連れ移動して下方に移動し、スプリングシート５１に衝合するとともに、段差部６１Ａとの間に隙間を形成し、油溜室２２の油をその外周経由でピストンロッド側油室２１Ａへ流入可能とする。伸側行程では、チェック弁６０はシリンダ１８から退出するピストンロッド２３に連れ移動して上方に移動し、段差部６１Ａに衝合して該段差部６１Ａとの間の隙間を閉じ、ピストンロッド側油室２１Ａの油が上述した圧側行程の逆経路で油溜室２２へ排出されることを阻止する。   The partition member 19 is allowed to flow oil from the oil reservoir chamber 22 to the piston rod side oil chamber 21A in the pressure side stroke, and flows from the piston rod side oil chamber 21A to the oil reservoir chamber 22 in the extension side stroke. A check valve 60 is provided to prevent this. A valve chamber 61 is provided on the inner periphery of the partition wall member 19 and the spring seat 51, and between the stepped portion 61 </ b> A on the upper end side of the valve chamber 61 and the backup spring 62 on the spring seat 51 on the lower end side of the valve chamber 61. The flange 60A of the check valve 60 is accommodated. The flange 60A of the check valve 60 is shorter than the distance between the stepped portion 61A and the spring seat 51, and a lateral groove is formed on the lower end surface. The flange 60A of the check valve 60 is provided so that the inner periphery of the valve chamber 61 can be displaced vertically. The outer periphery of the flange 60 </ b> A of the check valve 60 forms a flow path that allows oil to flow from the oil reservoir chamber 22 to the piston rod side oil chamber 21 </ b> A with the inner periphery of the valve chamber 61. The check valve 60 includes a bush 63 that is slidably supported by the piston rod 23 and is press-fitted into the inner periphery thereof. In the pressure side stroke, the check valve 60 moves along with the piston rod 23 entering the cylinder 18 and moves downward, abuts against the spring seat 51, and forms a gap with the step portion 61A. 22 oil can flow into the piston rod side oil chamber 21A via its outer periphery. In the extension side stroke, the check valve 60 moves along with the piston rod 23 that retreats from the cylinder 18 and moves upward. The check valve 60 collides with the stepped portion 61A to close the gap between the stepped portion 61A and the piston rod side. The oil in the oil chamber 21A is prevented from being discharged to the oil reservoir 22 through the reverse path of the pressure side stroke described above.

また、隔壁部材１９に、伸側行程で外側作動油室２０の油を油溜室２２へ流す体積補償用絞り流路６４を設けている。尚、隔壁部材１９に設ける体積補償用絞り流路６４は、伸側行程で内側作動油室２１のピストンロッド側油室２１Ａの油を油溜室２２へ流すものであっても良い。   Further, the partition member 19 is provided with a volume compensating throttle passage 64 for flowing the oil in the outer hydraulic oil chamber 20 to the oil reservoir chamber 22 in the extension side stroke. The volume compensation throttle channel 64 provided in the partition wall member 19 may flow the oil in the piston rod side oil chamber 21A of the inner working oil chamber 21 to the oil reservoir chamber 22 in the extension side stroke.

本実施例では、外側作動油室２０に臨む隔壁部材１９の下端面から油溜室２２へ向かう連通路６５を該隔壁部材１９に設け、この連通路６５が開口する隔壁部材１９の上端の環状バルブシートの平坦面に薄い平板からなるドーナツ状ベンディングバルブ６６を添設し、懸架スプリング３０により隔壁部材１９の側に押圧されるバルブ押え６７の下端面外周部によりベンディングバルブ６６の外周部を隔壁部材１９の環状バルブシート外周部との間に挟持する。バルブ押え６７の外周には、インナチューブ１２の内周に液密に挿着されるＯリングからなるシール部材６８が装填される。バルブ押え６７の下端面は、外周側から内周側に向けて、隔壁部材１９の平坦な環状バルブシートから徐々に離隔する湾曲面をなす。これにより、ベンディングバルブ６６の内周部は、伸側行程で環状油室１７から外側作動油室２０に排出される油の排出量のうち、環状油室１７の容積減少分ΔＳ1（排出量）がピストンロッド２３の容積減少分ΔＳ2を超える余剰分の油により加圧されてバルブ押え６７の下端面の湾曲に沿うように反り曲げられ、隔壁部材１９の環状バルブシートとの間に体積補償用絞り流路６４を形成する。上述の余剰分の油が体積補償用絞り流路６４から油溜室２２へ排出されることになる。   In the present embodiment, a communication path 65 from the lower end surface of the partition wall member 19 facing the outer hydraulic oil chamber 20 to the oil reservoir chamber 22 is provided in the partition wall member 19, and an annular shape at the upper end of the partition wall member 19 where the communication path 65 opens. A donut-shaped bending valve 66 made of a thin flat plate is attached to the flat surface of the valve seat, and the outer peripheral portion of the bending valve 66 is separated by the outer peripheral portion of the lower end surface of the valve presser 67 pressed against the partition member 19 side by the suspension spring 30. The member 19 is sandwiched between the outer peripheral part of the annular valve seat. On the outer periphery of the valve presser 67, a seal member 68 made of an O-ring inserted into the inner periphery of the inner tube 12 in a liquid-tight manner is loaded. The lower end surface of the valve retainer 67 forms a curved surface that gradually separates from the flat annular valve seat of the partition wall member 19 from the outer peripheral side toward the inner peripheral side. As a result, the inner circumferential portion of the bending valve 66 has a volume decrease ΔS1 (discharge amount) of the annular oil chamber 17 out of the amount of oil discharged from the annular oil chamber 17 to the outer hydraulic oil chamber 20 in the extension stroke. Is pressurized by excess oil exceeding the volume decrease ΔS2 of the piston rod 23, warped and bent along the curvature of the lower end surface of the valve presser 67, and is used for volume compensation between the annular valve seat of the partition wall member 19 A throttle channel 64 is formed. The surplus oil described above is discharged from the volume compensation throttle passage 64 to the oil reservoir chamber 22.

更に、隔壁部材１９に、伸側行程の外側作動油室２０の一定圧力以上の油を油溜室２２へ逃がすブロー弁６９を設けている。本実施例では、ブロー弁６９をベンディングバルブ６６とバルブ押え６７の組合せにより構成する。即ち、外側作動油室２０の圧力が懸架スプリング３０のばね力に打ち勝つとき、外側作動油室２０の圧力が懸架スプリング３０のばね力に抗してベンディングバルブ６６の全体及びバルブ押え６７を隔壁部材１９の環状バルブシートから押し上げ、外側作動油室２０の油を隔壁部材１９の連通路６５から油溜室２２へ逃がす。   Further, the partition member 19 is provided with a blow valve 69 for letting oil having a pressure equal to or higher than that in the outer working oil chamber 20 in the extension side stroke to the oil reservoir chamber 22. In this embodiment, the blow valve 69 is constituted by a combination of a bending valve 66 and a valve presser 67. That is, when the pressure of the outer hydraulic oil chamber 20 overcomes the spring force of the suspension spring 30, the pressure of the outer hydraulic oil chamber 20 resists the spring force of the suspension spring 30, and the entire bending valve 66 and the valve presser 67 are separated from the partition member. The oil in the outer hydraulic oil chamber 20 is released from the communication passage 65 of the partition wall member 19 to the oil reservoir chamber 22.

フロントフォーク１０の動作は以下の如くになる。
（圧側行程）
圧側行程で、ピストン側油室２１Ｂの油が圧側ディスクバルブ４１Ａを開いてピストンロッド側油室２１Ａに移送される。また、シリンダ１８に進入するピストンロッド２３の進入容積分の作動油がピストン側油室２１Ｂからシリンダ１８の下絞り孔２８を通って外側作動油室２０に移送され、外側作動油室２０からインナチューブ１２の連通孔２９を通って環状油室１７に補給される。このとき、環状油室１７の容積増加分ΔＳ1（補給量）がピストンロッド２３の容積増加分ΔＳ2より大きいから、環状油室１７への油の必要補給量のうち、（ΔＳ1−ΔＳ2）の不足分が油溜室２２からチェック弁６０を介して補給される。 The operation of the front fork 10 is as follows.
(Pressure side stroke)
In the pressure side stroke, the oil in the piston side oil chamber 21B opens the pressure side disk valve 41A and is transferred to the piston rod side oil chamber 21A. Further, the hydraulic oil corresponding to the volume of the piston rod 23 entering the cylinder 18 is transferred from the piston-side oil chamber 21 </ b> B through the lower throttle hole 28 of the cylinder 18 to the outer hydraulic oil chamber 20. The annular oil chamber 17 is supplied through the communication hole 29 of the tube 12. At this time, since the volume increase ΔS1 (replenishment amount) of the annular oil chamber 17 is larger than the volume increase ΔS2 of the piston rod 23, the required amount of oil supplied to the annular oil chamber 17 is insufficient (ΔS1−ΔS2). Minutes are replenished from the oil reservoir 22 through the check valve 60.

この圧側行程では、前述した通り、圧側ディスクバルブ４１Ａの撓み変形により圧側減衰力を発生する。   In the compression side stroke, as described above, a compression side damping force is generated by the bending deformation of the compression side disk valve 41A.

（伸側行程）
伸側行程で、ピストンロッド側油室２１Ａの油が伸側ディスクバルブ４２Ａを開いてピストン側油室２１Ｂに移送される。また、シリンダ１８から退出するピストンロッド２３の退出容積分の作動油が環状油室１７からインナチューブ１２の連通孔２９を通って外側作動油室２０に排出され、外側作動油室２０からシリンダ１８の下絞り孔２８を通ってピストン側油室２１Ｂに移送される。このとき、環状油室１７の容積減少分ΔＳ1（排出量）がピストンロッド２３の容積減少分ΔＳ2より大きいから、環状油室１７からの油の排出量のうち、（ΔＳ1−ΔＳ2）の余剰分が体積補償用絞り流路６４を通って油溜室２２へ排出される。 (Extension process)
In the extension stroke, the oil in the piston rod side oil chamber 21A is transferred to the piston side oil chamber 21B by opening the extension side disk valve 42A. Further, the hydraulic oil corresponding to the retraction volume of the piston rod 23 retreating from the cylinder 18 is discharged from the annular oil chamber 17 through the communication hole 29 of the inner tube 12 to the outer hydraulic oil chamber 20 and from the outer hydraulic oil chamber 20 to the cylinder 18. Is transferred to the piston-side oil chamber 21B through the lower throttle hole 28. At this time, since the volume decrease ΔS1 (discharge amount) of the annular oil chamber 17 is larger than the volume decrease ΔS2 of the piston rod 23, the excess of (ΔS1−ΔS2) of the oil discharge amount from the annular oil chamber 17 Is discharged to the oil reservoir 22 through the volume compensation throttle passage 64.

この伸側行程では、前述した通り、伸側ディスクバルブ４２Ａの撓み変形により伸側減衰力を発生する。また、上述の絞り流路６４の通路抵抗による伸側減衰力も発生する。   In this extension side stroke, as described above, the extension side damping force is generated by the bending deformation of the extension side disk valve 42A. Further, the extension side damping force due to the passage resistance of the throttle channel 64 is also generated.

本実施例によれば以下の作用効果を奏する。
(a)伸側行程で、環状油室１７に連通している外側作動油室２０の圧力を以下の理由で上げることがないから、外側作動油室２０の高圧油が環状油室１７に及んで、アウタチューブ１１の内周の開口部で環状油室１７をシールしているシール材を破損することがない。 According to the present embodiment, the following operational effects can be obtained.
(a) In the extension stroke, the pressure of the outer hydraulic oil chamber 20 communicating with the annular oil chamber 17 is not increased for the following reason, so that the high pressure oil in the outer hydraulic oil chamber 20 reaches the annular oil chamber 17. Thus, the sealing material that seals the annular oil chamber 17 at the inner peripheral opening of the outer tube 11 is not damaged.

(a-1)下絞り孔２８を設けたことで、ピストンロッド２３の退出容積補償の油を外側作動油室２０から下絞り孔２８を介してピストン側油室２１Ｂに補給できる。これにより、外側作動油室２０の圧力を低くすることができる。尚、下絞り孔２８がない場合は、外側作動油室２０の油を上絞り孔２７から伸側行程の故に高圧になっているピストンロッド側油室２１Ａ経由でピストン側油室２１Ｂに補給する必要があり、外側作動油室２０の圧力は高圧のピストンロッド側油室２１Ａと同等以上でなければならなくなる。   (a-1) By providing the lower throttle hole 28, the oil for compensating the withdrawal volume of the piston rod 23 can be supplied from the outer hydraulic oil chamber 20 to the piston-side oil chamber 21B through the lower throttle hole 28. Thereby, the pressure in the outer hydraulic oil chamber 20 can be lowered. If there is no lower throttle hole 28, the oil in the outer hydraulic oil chamber 20 is supplied from the upper throttle hole 27 to the piston-side oil chamber 21B via the piston rod-side oil chamber 21A that is at a high pressure due to the extension side stroke. Therefore, the pressure in the outer hydraulic oil chamber 20 must be equal to or higher than that of the high pressure piston rod side oil chamber 21A.

(a-2)下絞り孔２８を設けたことで、ピストンロッド２３の退出容積補償の油を外側作動油室２０から下絞り孔２８を介してピストン側油室２１Ｂに補給できる。これにより、上絞り孔２７をピストンロッド２３の退出容積補償の油の流路とする必要がなくなって絞ることができるようになるから、減衰力発生装置４０を高減衰に設定しても、伸側減衰発生時にピストンロッド側油室２１Ａの高圧が直接外側作動油室２０にかかることがなくなり、外側作動油室２０の圧力が上がらない。   (a-2) By providing the lower throttle hole 28, the oil for compensating the withdrawal volume of the piston rod 23 can be supplied from the outer hydraulic oil chamber 20 to the piston-side oil chamber 21B through the lower throttle hole 28. This eliminates the need for the upper restricting hole 27 as an oil flow path for the retraction volume compensation of the piston rod 23, so that the restriction can be made even if the damping force generator 40 is set to high attenuation. When the side damping occurs, the high pressure of the piston rod side oil chamber 21A is not directly applied to the outer hydraulic oil chamber 20, and the pressure of the outer hydraulic oil chamber 20 does not increase.

(a-3)上絞り孔２７を下絞り孔２８より強く絞ったから、ピストンロッド２３の退出容積補償の油を外側作動油室２０から下絞り孔２８を介してピストン側油室２１Ｂに補給するとき、外側作動油室２０の圧力が上がらない。   (a-3) Since the upper throttle hole 27 is squeezed more strongly than the lower throttle hole 28, the oil for compensating the withdrawal volume of the piston rod 23 is supplied from the outer hydraulic oil chamber 20 to the piston-side oil chamber 21B through the lower throttle hole 28. At this time, the pressure in the outer hydraulic oil chamber 20 does not increase.

(a-4)環状油室１７の油の余剰分が外側作動油室２０経由で体積補償用絞り流路６４から油溜室２２へ排出されるとき、必要以上の油が排出しないように体積補償用絞り流路６４を絞っているが、外側作動油室２０の圧力が下がれば、相対的に体積補償用絞り流路６４での設定減衰力も下がり、結果として外側作動油室２０の圧力が上がらない。   (a-4) When excess oil in the annular oil chamber 17 is discharged from the volume compensation throttle channel 64 to the oil reservoir chamber 22 via the outer hydraulic oil chamber 20, the volume is prevented so that excessive oil is not discharged. Although the compensation throttle channel 64 is throttled, if the pressure in the outer hydraulic fluid chamber 20 decreases, the set damping force in the volume compensation throttle channel 64 also decreases relatively, and as a result, the pressure in the outer hydraulic fluid chamber 20 decreases. Does not rise.

尚、圧側行程では、環状油室１７内に油が補給され、環状油室１７の圧力は負圧になるから、この環状油室１７をシールするオイルシール１１Ｂが破損するおそれはない。   In the pressure side stroke, oil is replenished into the annular oil chamber 17 and the pressure in the annular oil chamber 17 becomes negative. Therefore, there is no possibility that the oil seal 11B that seals the annular oil chamber 17 is broken.

(b)体積補償用絞り流路６４が外側作動油室２０の油を油溜室２２へ流すように設けられ、伸側行程の高ピストン２６速度に起因して外側作動油室２０の油の圧力が一定圧力以上に上昇するときには、直ちにブロー弁６９が開き、この外側作動油室２０の油を油溜室２２へ逃がす。これにより、高圧の外側作動油室２０の油がインナチューブ１２の連通孔２９を介して環状油室１７に及ぶことがない。   (b) A volume compensation throttle passage 64 is provided so as to flow the oil in the outer hydraulic oil chamber 20 to the oil reservoir chamber 22, and the oil in the outer hydraulic oil chamber 20 is caused by the high piston 26 speed in the extension stroke. When the pressure rises above a certain pressure, the blow valve 69 is immediately opened, and the oil in the outer working oil chamber 20 is released to the oil reservoir chamber 22. Thereby, the oil in the high-pressure outer hydraulic oil chamber 20 does not reach the annular oil chamber 17 through the communication hole 29 of the inner tube 12.

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。例えば、本発明のブロー弁６９は、外側作動油室２０に対し、体積補償用絞り流路６４と並列的に設けられるものでも良い。   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. For example, the blow valve 69 of the present invention may be provided in parallel to the volume compensation throttle passage 64 with respect to the outer hydraulic oil chamber 20.

また、本発明の体積補償用絞り流路６４の絞り度合が弱く、あまり絞られていないときには、ブロー弁６９を設けることは必須でない。   In addition, when the degree of throttling of the volume compensating throttling channel 64 of the present invention is weak and not so narrow, it is not essential to provide the blow valve 69.

図１は油圧緩衝器の全体を示す断面図である。FIG. 1 is a sectional view showing the entire hydraulic shock absorber. 図２は図１の下部拡大断面図である。2 is an enlarged cross-sectional view of the lower part of FIG. 図３は図１の中間部拡大断面図である。FIG. 3 is an enlarged cross-sectional view of the middle part of FIG. 図４は図１の上部拡大断面図である。FIG. 4 is an enlarged cross-sectional view of the upper part of FIG. 図５は図３の要部拡大断面図である。FIG. 5 is an enlarged cross-sectional view of the main part of FIG.

符号の説明Explanation of symbols

１０ フロントフォーク（油圧緩衝器）
１１ アウタチューブ
１２ インナチューブ
１７ 環状油室
１８ シリンダ
１９ 隔壁部材
２０ 外側作動油室
２１ 内側作動油室
２１Ａ ピストンロッド側油室
２１Ｂ ピストン側油室
２２ 油溜室
２３ ピストンロッド（ピストン支持部材）
２６ ピストン
２７ 上絞り孔
２８ 下絞り孔
２９ 連通孔
６０ チェック弁
６４ 体積補償用絞り流路
６９ ブロー弁 10 Front fork (hydraulic shock absorber)
11 outer tube 12 inner tube 17 annular oil chamber 18 cylinder 19 partition member 20 outer hydraulic oil chamber 21 inner hydraulic oil chamber 21A piston rod side oil chamber 21B piston side oil chamber 22 oil reservoir chamber 23 piston rod (piston support member)
26 Piston 27 Upper throttle hole 28 Lower throttle hole 29 Communication hole 60 Check valve 64 Volume compensation throttle channel 69 Blow valve

Claims (2)

車体側のアウタチューブ内に車軸側のインナチューブを摺動自在に挿入し、
インナチューブの内部にシリンダを立設し、
インナチューブとシリンダの上部に隔壁部材を設け、隔壁部材の下部のインナチューブとシリンダの間に外側作動油室を、シリンダの内部に内側作動油室をそれぞれ区画するとともに、隔壁部材の上部に油溜室を区画し、
アウタチューブ側に取付けたピストン支持部材を、隔壁部材に通してシリンダ内の内側作動油室に挿入し、ピストン支持部材の先端部にシリンダ内を摺動するピストンを設け、
シリンダ内の内側作動油室をピストンロッドが収容されるピストンロッド側油室と、ピストンロッドが収容されないピストン側油室に区画し、
インナチューブ内の外側作動油室と、シリンダ内のピストンロッド側油室を上絞り孔により連通するとともに、インナチューブ内の外側作動油室と、シリンダ内のピストン側油室を下絞り孔により連通し、伸側行程で上絞り孔を下絞り孔より強く絞り、
アウタチューブの内周とインナチューブの外周との間に環状油室を区画し、この環状油室をインナチューブに設けた連通孔を介してインナチューブ内の外側作動油室に連通し、
環状油室の断面積をピストン支持部材の断面積より大きく形成し、
ピストン支持部材が内側作動油室から退出する伸側行程で内側作動油室又は外側作動油室の油を油溜室へ流す体積補償用絞り流路と、伸側行程で内側作動油室又は外側作動油室から油溜室への油の流れを阻止するチェック弁とを有してなる油圧緩衝器。 Insert the inner tube on the axle side slidably into the outer tube on the vehicle body side,
Install a cylinder upright inside the inner tube,
A partition member is provided at the upper part of the inner tube and the cylinder, an outer hydraulic oil chamber is defined between the inner tube and the cylinder at the lower part of the partition member, and an inner hydraulic oil chamber is defined inside the cylinder. Partition the reservoir,
The piston support member attached to the outer tube side is inserted into the inner hydraulic oil chamber in the cylinder through the partition member, and a piston that slides in the cylinder is provided at the tip of the piston support member.
The inside hydraulic oil chamber in the cylinder is divided into a piston rod side oil chamber in which the piston rod is accommodated and a piston side oil chamber in which the piston rod is not accommodated,
The outer hydraulic oil chamber in the inner tube communicates with the piston rod side oil chamber in the cylinder through the upper throttle hole, and the outer hydraulic oil chamber in the inner tube communicates with the piston side oil chamber in the cylinder through the lower throttle hole. The upper throttle hole is squeezed more strongly than the lower throttle hole in the extension stroke,
An annular oil chamber is defined between the inner periphery of the outer tube and the outer periphery of the inner tube, and the annular oil chamber communicates with an outer hydraulic oil chamber in the inner tube through a communication hole provided in the inner tube.
Forming the cross-sectional area of the annular oil chamber larger than the cross-sectional area of the piston support member;
A volume compensation throttle channel for flowing the oil in the inner hydraulic fluid chamber or the outer hydraulic fluid chamber to the oil reservoir chamber during the extension stroke when the piston support member retreats from the inner hydraulic fluid chamber, and the inner hydraulic fluid chamber or the outer portion during the extension stroke. A hydraulic shock absorber having a check valve for preventing the flow of oil from the hydraulic oil chamber to the oil reservoir chamber. 前記伸側行程の外側作動油室の一定圧力以上の油を油溜室へ逃がすブロー弁を設けた請求項１に記載の油圧緩衝器。   2. The hydraulic shock absorber according to claim 1, further comprising a blow valve configured to release oil having a pressure equal to or higher than a predetermined pressure in the outer hydraulic oil chamber in the extension stroke to the oil reservoir chamber.
JP2008048420A 2008-02-28 2008-02-28 Hydraulic shock absorber Withdrawn JP2009204118A (en)

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Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2012117635A (en) * 2010-12-02 2012-06-21 Kyb Co Ltd Shock absorber
JP2014240700A (en) * 2014-10-01 2014-12-25 カヤバ工業株式会社 Damper
EP2843257A4 (en) * 2012-04-27 2016-04-20 Kyb Corp Suspension device
JP2016070460A (en) * 2014-10-01 2016-05-09 Ｋｙｂモーターサイクルサスペンション株式会社 Front fork

Cited By (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2012117635A (en) * 2010-12-02 2012-06-21 Kyb Co Ltd Shock absorber
US9038792B2 (en) 2010-12-02 2015-05-26 Kayaba Industry Co., Ltd. Shock absorber
EP2843257A4 (en) * 2012-04-27 2016-04-20 Kyb Corp Suspension device
JP2014240700A (en) * 2014-10-01 2014-12-25 カヤバ工業株式会社 Damper
JP2016070460A (en) * 2014-10-01 2016-05-09 Ｋｙｂモーターサイクルサスペンション株式会社 Front fork

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