JPS63186009A - Hydraulic controller for hydraulic cylinder - Google Patents

Abstract

PURPOSE:To aim at miniaturization of pilot valves and opening/closing valves as well as simplify a countermeasure for sealing by leading lower pressure oil in another system to back pressure chambers on the spool sides of the respective pilot valves so as to control the opening/closing valves respectively. CONSTITUTION:Pilot oil passages 141, 142 are connected to the back pressure chambers 42, 92 of first and second valve bodies 40, 90, and then pilot valves 80, 100 are provided in the pilot oil passages 141, 142, while control oil passages 131, 133, which lead control oil pressure lower than operating oil pressure, are connected to the back pressure chambers 86, 106 of the respective pilot valves 80, 100, and further opening/closing valves 62, 66 are provided in the respective control oil passages 131, 135. Therefore, higher pressure oil hardly, acts on respective pilot valves 80, 100 and respective opening/closing valves 62, 66 so that the respective valves can be miniaturized. In addition, the sealing surface areas can be reduced so as to simplify a countermeasure for sealing.

Description

【発明の詳細な説明】 （産業上の利用分野） 本発明は油圧シリンダの油圧制御装置に関する。[Detailed description of the invention] (Industrial application field) The present invention relates to a hydraulic control device for a hydraulic cylinder.

（従来の技術） 特開昭５４−９９８８１号において、ポンプ順）ら油圧
シリンダへの作動油路に逆止弁とその下流側の第１弁体
及び上流側の第２弁体とを設け、該各弁体の背圧室には
パイロット圧油を導くパイロット油路をそれぞれ接続し
、該各パイロット油路に開閉弁をそれぞれ設けけて油圧
シリンダの作動を制御するようにしたことが開示される
。(Prior Art) In Japanese Patent Application Laid-Open No. 54-99881, a check valve, a first valve body on the downstream side thereof, and a second valve body on the upstream side thereof are provided in the hydraulic oil path from the pump to the hydraulic cylinder, It is disclosed that pilot oil passages for guiding pilot pressure oil are connected to the back pressure chambers of each of the valve bodies, and that each of the pilot oil passages is provided with an on-off valve to control the operation of the hydraulic cylinder. Ru.

（発明が解決しようとする問題点） このように従来は逆止弁の上下流に設けられる各弁体の
背圧室にパイロット圧油をそれぞれ導き、その各パイロ
ット油路にそれぞれ設けられる開閉弁にて油圧シリンダ
の作動を制御していたが、開閉弁を閉じて弁体の背圧室
にパイロット圧油を保持しておくには、そのパイロット
圧油は高圧°の作動油圧に打ち勝つべく高圧となるため
、それに耐えるべく大型で大容量の開閉弁を用い、且つ
高精度のシール対策を必要としていた。(Problems to be Solved by the Invention) In this way, conventionally, pilot pressure oil is guided into the back pressure chambers of each valve body provided upstream and downstream of a check valve, and on-off valves are provided in each pilot oil passage. In order to close the on-off valve and maintain pilot pressure oil in the back pressure chamber of the valve body, the pilot pressure oil must be under high pressure to overcome the high pressure of the working oil pressure. Therefore, in order to withstand this, it was necessary to use a large, large-capacity on-off valve and to take high-precision sealing measures.

そこで本発明の目的は、ポンプから油圧シリンダへの作
動油路に設けられる逆止弁の上下流の各弁体の背圧室へ
のパイロット圧油を別のポペットとスプールから成るパ
イロット弁でそれぞれ制御し、この各パイロット弁をそ
のスプール側背圧室に別系統の低圧油を導いてそれぞれ
開閉弁で制御することにより、開閉弁の小型小容量化が
図れるとともに、各々の弁体やパイロット弁が小型化さ
れ、ひいては油圧制御ユニットを小型化、軽量化し、シ
ール対策の容易化をも図れるようにした油圧シリンダの
油圧制御装置を提供するにある。Therefore, an object of the present invention is to supply pilot pressure oil to the back pressure chambers of each valve element upstream and downstream of the check valve provided in the hydraulic oil path from the pump to the hydraulic cylinder using separate pilot valves consisting of separate poppets and spools. By controlling each pilot valve with a separate system of low-pressure oil to its spool-side back pressure chamber and controlling each valve with an on-off valve, the on-off valve can be made smaller and smaller in capacity, and each valve body and pilot valve can be It is an object of the present invention to provide a hydraulic control device for a hydraulic cylinder, in which the hydraulic control unit is made smaller and lighter, and sealing measures can be easily taken.

（問題点を解決するための手段） 以上の問題を解決して目的を達成すべく本発明は、ポン
プ（３２）から油圧シリンダ（１０）への作動油路（１
１０）に逆止弁（３６）とその下流側の第１弁体（４０
）及び上流側の第２弁体（９０）とを設け、該答弁体（
４０）　、　（９０）の背圧室（４２）、　（９２）に
はパイロット圧油を導くパイロット油路（１４１）　、
（１４２）をそれぞれ接続し、該各パイロット油路（’
１４１）　、（１４２）にはポペット（８２）、（１０
２）とスプール（８３）　、　（１０３）を同軸上に配
置して成るパイロット弁（８０）　、　（１００）をそ
れぞれ設け、該各パイロット弁（８０）　、　（１００
）のスプール側背圧室（８６）　、　（１０６）にはポ
ンプ（３２）から前記作動油路（１１０）の作動油圧よ
り低圧の制御油圧を導く制御油路（１３１）　、（１３
５）をそれぞれ接続し、該各制御油路（１３］、）、（
１３５）には前記各パイロット弁（８０）、　（１００
）のスプール側背圧室（８６）　、（１０６）へ制御油
圧を給排するための開閉弁（６２）、（６６）を絞り弁
（６１）、（６５）を介してそれぞれ設けたことを特徴
とする。(Means for Solving the Problems) In order to solve the above problems and achieve the objectives, the present invention provides a hydraulic oil passage (1) from the pump (32) to the hydraulic cylinder (10).
10) includes a check valve (36) and a first valve body (40) on the downstream side thereof.
) and a second valve body (90) on the upstream side, and the answering body (
40), (90) back pressure chambers (42), (92) have pilot oil passages (141) that guide pilot pressure oil,
(142) respectively, and each pilot oil path ('
141), (142) have poppets (82), (10
2) and spools (83) and (103) are arranged coaxially to provide pilot valves (80) and (100), respectively.
) control oil passages (131), (13) which lead a control hydraulic pressure lower than the hydraulic pressure of the hydraulic oil passage (110) from the pump (32) to the spool-side back pressure chambers (86), (106).
5), respectively, and connect the respective control oil passages (13], ), (
135), each of the pilot valves (80), (100
) are provided with on-off valves (62) and (66) for supplying and discharging control hydraulic pressure to and from the spool-side back pressure chambers (86) and (106) via throttle valves (61) and (65), respectively. Features.

（作用） ポンプ（３２）から油圧シリンダ（１０）への作動油路
（１１０）に設けられる逆止弁（３６）の上下流の各弁
体（４０）　、　（９０）の背圧室（４２）、（９２）
へ゛のパイロット圧油を別のポペット（８２）　、　（
１０２）とスプール（８３）、　（１０３）から成るパ
イロット弁（８０）、（１００）でそれぞれ制御し、こ
の各パイロット弁（８０）　、（１００）をそのスプー
ル側背圧室（８６）、（１０６，）に別系統の低圧油を
導いてそれぞれ開閉弁（６２）　、（６５）で制御する
ので、弁体（４０）　、　（９０）の閉時に高圧となる
パイロット圧油なパイロット弁（８０）　、　（１００
）のポペット（８２）、（１０２）で受けられ、そのポ
ペット（８２）、　（１０２）を保持するスプール（８
３）　、　（１０３）には低圧油を導くだけで良くなり
、開閉弁（６２）、（６６）には高圧油がかからずに低
圧の制御油のみを制御すれば良く、従って開閉弁は小型
小容量化のものを採用することができ、そのシール面も
少なくなるためにシール対策も簡単なものになる。また
絞り弁（６１）、（６５）を設けたことにより弁体（４
０）、　（９０）の開閉速度の調整も行える。(Function) The back pressure chambers (42) of the upstream and downstream valve bodies (40) and (90) of the check valve (36) provided in the hydraulic oil path (110) from the pump (32) to the hydraulic cylinder (10) ), (92)
Transfer the pilot pressure oil to another poppet (82), (
102) and spools (83), (103), respectively, and each pilot valve (80), (100) is controlled by its spool side back pressure chamber (86), ( Since low pressure oil from a separate system is led to the pilot valve (80) and controlled by the on-off valves (62) and (65), the pilot pressure oil becomes high pressure when the valve bodies (40) and (90) are closed. ), (100
) is received by the poppets (82), (102) and holds the poppets (82), (102).
3), (103) need only introduce low-pressure oil, and the on-off valves (62) and (66) only need to control low-pressure control oil without applying high-pressure oil. It is possible to use a smaller and smaller capacity device, and the sealing surface is also reduced, making sealing measures simpler. In addition, by providing the throttle valves (61) and (65), the valve body (4)
0) and (90) can also be adjusted.

（実施例） 以下に添付図面を基に実施例を説明する。(Example) Examples will be described below based on the accompanying drawings.

第１図はトラクタの概略側面を示し、トラクタ（１）の
後方にはロータリ一作業機（２）が装備され、第２図に
も示すようにロータリ一作業機（２）はトラクタ（１）
後部に枢支された１本のアッパリンク（３）と２本のロ
アリンク（４）、（４）で支持され、またトラクタ（１
）後部上には昇降用の油圧シリンダ（１０）が設置され
、この油圧シリンダ（１０）により上下揺動される２木
のリフトアーム（５）、（５）とロアリンク（４）、（
４）とはそれぞれリフトロッド（６）、（６）にて枢着
され、更に一方のリフトロット（６）には水平制御用の
油圧シリンダ（２０）が組み込まれる。Figure 1 shows a schematic side view of the tractor, and the rear of the tractor (1) is equipped with a rotary work machine (2), and as shown in Figure 2, the rotary work machine (2) is attached to the tractor (1).
It is supported by one upper link (3) and two lower links (4), (4) which are pivotally supported at the rear, and the tractor (1
) A hydraulic cylinder (10) for lifting and lowering is installed on the rear part, and two wooden lift arms (5), (5) and a lower link (4), (
4) are pivotally connected to each other by lift rods (6) and (6), respectively, and one of the lift rods (6) is equipped with a hydraulic cylinder (20) for horizontal control.

第４図はその油圧回路を示し、昇降用の油圧シリンダ（
１０）は単動型シリンダ、水平制御用の油圧シリンダ（
２０）は複動型シリンダであり、タンク（３１）からポ
ンプ（３２）で汲み上げられた油は分流弁（３３）で二
手に分岐され、一方は単動型シリンダ（１０）の給排ボ
ート（１１）、他方は複動型シリンダ（２０）の給排ボ
ート（２１）、　（２２）へと流れ、またポンプ（３２
）から分流弁（３３）への油路（３４）にリリーフ弁（
３５）が設けられる。Figure 4 shows the hydraulic circuit, and shows the hydraulic cylinder for lifting (
10) is a single-acting cylinder, a hydraulic cylinder for horizontal control (
20) is a double-acting type cylinder, and the oil pumped up from the tank (31) by the pump (32) is branched into two parts by the diversion valve (33), and one side is the supply/discharge boat (20) of the single-acting type cylinder (10). 11), the other flows to the supply/discharge boats (21), (22) of the double-acting cylinder (20), and the pump (32).
) to the diversion valve (33) with a relief valve (
35) is provided.

分流弁（３３）から単動型シリンダ（１０）内のピスト
ン（１３）背面側の油室（１４）の給排ボート（１１）
への作動油路（１１０）には逆止弁（３６）か設けられ
、その下流に分岐油路（１１１）を介して第１油作動装
置（Ａ）を構成するポペット式の第１弁体（４０）か設
けられ、更に給排ボート（１１）には絞り弁（２１１）
、チェック弁（３１１）が内蔵され、調圧弁（１９）も
接続される。第１弁体（４０）はポペット（４１）の背
圧室（４２）内にスプリング（４３）を収納し、作動油
路（１１０）側のボート（４４）はポペット（４１）に
て開閉され、ポペット（４１）が開くと作動油はボート
（４５）からタンク（３１）へ戻される。Supply/discharge boat (11) from the diverter valve (33) to the piston (13) in the single-acting cylinder (10) and the oil chamber (14) on the back side
A check valve (36) is provided in the hydraulic oil passage (110) leading to the valve, and a poppet-type first valve body constituting the first oil-operated device (A) is provided downstream of the check valve (36) via a branch oil passage (111). (40), and a throttle valve (211) is provided on the supply/discharge boat (11).
, a check valve (311) is built-in, and a pressure regulating valve (19) is also connected. The first valve body (40) stores a spring (43) in the back pressure chamber (42) of the poppet (41), and the boat (44) on the hydraulic oil path (110) side is opened and closed by the poppet (41). , when the poppet (41) opens, hydraulic fluid is returned from the boat (45) to the tank (31).

分流弁（３３）から複動型シリンダ（２０）の給排ボー
ト（２１）、（２２）への作動油路（１２０）には油作
動装置（Ｃ）をなすスプール式の方向切換弁（５０）が
設けられ、その下流で作動油路（１２０）は二手に分岐
され、一方の油路（１２１）は複動型シリンダ（２０）
内のピストン（２３）下方側の油室（２４）の給排ボー
ト（２１）、他方の油路（１２２）はピストン（２３）
上方側の油室（２５）の給排ボート（２２）に接続され
゛る。方向切換弁（５０）はスプール（５１）の両方に
背圧室（５２）、（５３）を有し、その左側の一方のみ
にスプリング（５４）を収納し、スプール（５１）には
左右のランド（５５）、（５６）とその両側方及び中間
を連続する油路（５７）が形成される。この油路（５７
）の中央が供給ボート（５８）に臨むと両端のボート（
５９）、（５９）から作動油がタンク（３１）に戻され
る。A hydraulic oil path (120) from the diverter valve (33) to the supply/discharge boats (21) and (22) of the double-acting cylinder (20) has a spool-type directional control valve (50) that forms the oil-operated device (C). ), downstream of which the hydraulic oil passage (120) is branched into two, and one oil passage (121) is connected to a double-acting cylinder (20).
The inner piston (23) is the supply/discharge boat (21) of the lower oil chamber (24), and the other oil passage (122) is the piston (23).
It is connected to the supply/discharge boat (22) of the upper oil chamber (25). The directional control valve (50) has back pressure chambers (52) and (53) on both sides of the spool (51), and a spring (54) is housed in only one of the left sides, and the spool (51) has back pressure chambers (52) and (53) on both sides. An oil passage (57) is formed that is continuous with the lands (55), (56), on both sides thereof, and in the middle. This oil road (57
) facing the supply boat (58), the boats at both ends (
Hydraulic oil is returned to the tank (31) from (59) and (59).

複動型シリンダ（２０）への作動油路（１２０）の上流
側には分岐油路（１２：ｌ）か設けられ、この分岐油路
（１２３）に絞り弁（３７）を介して減圧弁（３８）か
接続され、この減圧弁（３８）の下流に制御油路（１３
０）が設けられ、更に減圧弁（３８）と並列に絞り弁（
３９）が設けられる。制御油路（１３０）には減圧弁（
３８）により減圧されて作動油圧より低圧の制御油圧が
流れ、この制御油路（１３０）には各種制御弁が設けら
れる。A branch oil passage (12:l) is provided on the upstream side of the hydraulic oil passage (120) to the double-acting cylinder (20), and a pressure reducing valve is connected to this branch oil passage (123) via a throttle valve (37). (38) is connected to the control oil passage (13) downstream of this pressure reducing valve (38).
0) is provided, and a throttle valve (38) is provided in parallel with the pressure reducing valve (38).
39) is provided. A pressure reducing valve (
38), a control oil pressure lower than the working oil pressure flows, and various control valves are provided in this control oil passage (130).

制御油路（１３０）は下流で二手に分岐され、その両方
の油路（１：１１）　、（１：１２）には絞り弁（６１
）、（７１）を介して電磁式の第１開閉弁（６２）、（
７２）がそれぞれ接続され、左側の第１開閉弁（６２）
は単動型シリンダ（１０）への作動油路（１１０）に設
けた前記第１弁体（４０）を制御し、右側の第１開閉弁
（７２）は複動型シリンダ（２０）への作動油路（１２
０）に設けた方向切換弁（５０）を制御する。The control oil passage (130) is branched into two downstream, and both oil passages (1:11) and (1:12) are equipped with throttle valves (61).
), (71) to the electromagnetic first on-off valve (62), (
72) are connected respectively, and the first on-off valve (62) on the left side
controls the first valve body (40) provided in the hydraulic oil passage (110) to the single-acting cylinder (10), and the first on-off valve (72) on the right side controls the hydraulic oil passage (110) to the single-acting cylinder (10). Hydraulic oil path (12
0) is controlled.

即ち左側の第１開閉弁（６２）の上流において分岐した
油路（１３３）に第１パイロツト弁（８０）を接続し、
そのボート（８１）と第１弁体（４０）の背圧室（４２
）とをパイロット油路（１４１）て接続する。第１パイ
ロツト弁（８０）はボート（８１）を開閉するポペット
弁（１８２）とスプール弁（２８２）とを一体とし、ボ
ート（８１）をこれらの間の溝部に臨ませたポペット（
８２）とスプール（８３）とを同軸上に配置して成り、
ポペット（８２）の背圧室（８４）にスプリング（８５
）を収納し、スプール（８３）の背圧室（８６）に制御
油路（１３：ｌ）を接続する。また右側の第１開閉弁（
７２）の上流において分岐した油路（１３４）を方向切
換弁（５０）の左側の背圧室（５２）に接続する。That is, the first pilot valve (80) is connected to the oil passage (133) branched upstream of the first on-off valve (62) on the left side,
The boat (81) and the back pressure chamber (42) of the first valve body (40)
) is connected to the pilot oil passage (141). The first pilot valve (80) integrates a poppet valve (182) for opening and closing the boat (81) and a spool valve (282).
82) and a spool (83) are arranged on the same axis,
A spring (85) is installed in the back pressure chamber (84) of the poppet (82).
), and the control oil line (13:l) is connected to the back pressure chamber (86) of the spool (83). Also, the first on-off valve on the right side (
72) is connected to the back pressure chamber (52) on the left side of the directional control valve (50).

ここで、第１パイロツト弁（８０）は、スプリング（８
５）の付勢力だけで、ポペット弁（１８２）とスプール
弁（２８２）とを一体としてボート（８１）をこれらの
間の溝部に臨ませたポペット（８２）かパイロット油路
（１４１）側のボート（８１）を閉じる構造となってい
る。このため、ボート（８１）を開くにはスプール（８
３）の背圧室（８６）にスプリング（８５）の付勢力に
打ち勝つだけの低圧油を導くたけて良い。またポペット
とスプールを一体に形成した場合はケースも含んで高精
度の加工を要するが、実施例のように別体て構成すれば
、加工精度はラフなもので足りる。Here, the first pilot valve (80) has a spring (80).
5), the poppet valve (182) and the spool valve (282) are integrated and the boat (81) faces the groove between them. It has a structure that closes the boat (81). Therefore, in order to open the boat (81), the spool (8
3) Low pressure oil sufficient to overcome the biasing force of the spring (85) may be introduced into the back pressure chamber (86). Furthermore, if the poppet and spool are integrally formed, high-precision machining is required including the case, but if they are constructed separately as in the embodiment, rough machining accuracy is sufficient.

更に制御油路（１３０）は上流ても二手に分岐され、そ
の両方の油路（１３５）　、（１３６）にも絞り弁（６
５）　、　（７５）を介して電磁式の第２開閉弁（６６
）　。Furthermore, the control oil passage (130) is also branched into two upstream, and both oil passages (135) and (136) are also equipped with a throttle valve (6).
5), the second electromagnetic on-off valve (66) via (75)
).

（７６）かそれぞれ接続され、左側の第２開閉弁（６６
）は単動型シリンダ（ｌＯ）への作動油路（１１０）の
逆止弁（３６）の上流側に設けられる第２油作動、装置
（Ｂ）を構成する第２弁体（９０）を制御し、右側の第
２開閉弁（７６）は複動型シリンダ（２０）への作動油
路（１２０）に設けた方向切換弁（５０）を制御する。(76) are connected to the second on-off valve (66) on the left side.
) is a second oil actuator provided on the upstream side of the check valve (36) in the hydraulic oil path (110) to the single-acting cylinder (lO), and the second valve body (90) constituting the device (B). The second on-off valve (76) on the right side controls the directional switching valve (50) provided in the hydraulic oil path (120) to the double-acting cylinder (20).

即ち単動型シリンダ（１０）への作動油路（１１０）の
逆止弁（３６）の上流側にも分岐油路（１１２）を介し
てポペット式の第２弁体（９０）が設けられ、この第２
弁体（９０）もポペット（９１）の背圧室（９２）内に
スプリング（９３）を収納し、作動油路（１１０）側の
ボート（９４）はポペット（９１）にて開閉され、ポペ
ット（９１）が開くと作動油はボート（９５）からタン
クへ戻される。左側の第２開閉弁（６６）の上流におい
て分岐した油路（１３７）にも第２パイロツト弁（１０
０）を接続し、そのボート（１０１）と第２弁体（９０
）の背圧室（９２）とをパイロット油路（１４２）で接
続する。第２パイロツト弁（１００）もボート（１０１
）を開閉するポペット弁（１１０２）とスプール弁（２
１０２）とを一体とし、ボート（１０１）をこれらの間
の溝部に臨ませたポペット（１０２）とスプール（１０
３）とを同軸上に配置して成り、ポペット（１０２）の
背圧室（１０４）にスプリング（１０５）を収納し、ス
プール（１０：ｌ）の背圧室（１０６）に制御油路（１
３７）を接続する。また右側の第２開閉弁（７５）の上
流において分岐した油路（１３８）を方向切換弁（５０
）の右側の背圧室（５３）に接続する。That is, a poppet-type second valve body (90) is also provided on the upstream side of the check valve (36) in the hydraulic oil path (110) to the single-acting cylinder (10) via the branch oil path (112). , this second
The valve body (90) also houses a spring (93) in the back pressure chamber (92) of the poppet (91), and the boat (94) on the hydraulic oil path (110) side is opened and closed by the poppet (91). When (91) is opened, hydraulic oil is returned from the boat (95) to the tank. There is also a second pilot valve (10
0) and the boat (101) and the second valve body (90
) is connected to the back pressure chamber (92) by a pilot oil passage (142). The second pilot valve (100) is also connected to the boat (101).
) and a spool valve (2) that opens and closes the poppet valve (1102).
The poppet (102) and the spool (102) are integrated with the spool (102) and the boat (101) faces the groove between them.
3) are arranged coaxially, a spring (105) is stored in the back pressure chamber (104) of the poppet (102), and a control oil path ( 1
37). In addition, the oil passage (138) branched upstream of the second on-off valve (75) on the right side is connected to the directional control valve (50).
) is connected to the back pressure chamber (53) on the right side.

以上の各種制御弁及び油路は第３図に示すように油圧制
御ユニット（１５０）に内蔵され、この油圧制御ユニッ
ト（１５０）は前記昇降用の単動型シリンダ（１０）の
側面に設置される。The various control valves and oil passages described above are built into a hydraulic control unit (150) as shown in FIG. 3, and this hydraulic control unit (150) is installed on the side of the single-acting cylinder (10) for lifting. Ru.

次に第４図の油圧回路を基にその機能を説明する。Next, its function will be explained based on the hydraulic circuit shown in FIG.

先ず作業機（２）の昇降操作から説明するに上昇させる
場合は、左側の第１開閉弁（６２）を開き、第２開閉弁
（６６）を閉じる。第１開閉弁（６２）の開により制御
油はボート（６３）からタンク（３１）へ戻され、第１
パイロツト弁（８０）のボート（８１）がポペット（８
２）にて閉じられ、第１弁体（４０）の背圧室（４２）
に作動油路の油圧によりパイロット圧油が満たされ、ス
プリング（４３）の付勢と併せてポペット（４１）が前
進し、ボート（４４）が閉じられる。また第２開閉弁（
６６）の閉により低圧の制御油が第２パイロツト弁（１
００）のスプール（１０：ｌ）の背圧室（１０６）に導
かれ、スプール（１０３）の前進でボート（１０１）か
ポペット（１０２）にて閉じられ、第２弁体（９０）の
背圧室（９２）に作動油路の油圧によりパイロット圧油
が満たされ、スプリング（９３）の付勢と併せてポペッ
ト（９１）が前進し、ボート（９４）が閉じられる。First, the lifting operation of the working machine (2) will be explained. When raising the working machine (2), the first opening/closing valve (62) on the left side is opened and the second opening/closing valve (66) is closed. By opening the first on-off valve (62), the control oil is returned from the boat (63) to the tank (31), and the first on-off valve (62) is opened.
The boat (81) of the pilot valve (80) is
2), the back pressure chamber (42) of the first valve body (40)
The pilot pressure oil is filled by the hydraulic pressure of the hydraulic oil passage, and the poppet (41) moves forward together with the biasing of the spring (43), and the boat (44) is closed. Also, the second on-off valve (
66) is closed, low-pressure control oil flows to the second pilot valve (1
00) is guided to the back pressure chamber (106) of the spool (10:l), and is closed by the boat (101) or poppet (102) as the spool (103) advances, and the back pressure of the second valve body (90) is The pressure chamber (92) is filled with pilot pressure oil by the hydraulic pressure of the hydraulic oil passage, and the poppet (91) moves forward together with the biasing of the spring (93) to close the boat (94).

このように第１及び第２の両弁体（４０）、　（９０）
が閉じられているので、高圧の作動油は単動型シリンダ
（１０）の油室（１４）に送り込まれ、これによりリフ
トアーム（５）、リフドロ・ンド（６）等を介して作業
ｍ（２）が上昇する。In this way, both the first and second valve bodies (40), (90)
is closed, high-pressure hydraulic oil is sent into the oil chamber (14) of the single-acting cylinder (10), which causes the work m ( 2) increases.

下降させる場合は、逆に第１開閉弁（６２）を閉じ、第
２開閉弁（６６）を開く。第１開閉弁（６２）の閉によ
り低圧の制御油か第１パイロツト弁（８０）のスプール
（８３）の背圧室（８６）に導かれ、スプール（８３）
の前進でボート（８１）をポペット（８２）が開き、第
１弁体（４０）の背圧室（４２）のパイロット圧油が背
圧室（８４）を通ってタンク（３１）に戻され、高圧の
作動油によりスプリング（４３）に抗してポペット（４
１）か後退し、ボー）−（４４）が開かれる。第２開閉
弁（６６）の開により制御油はボー）　（６７）からタ
ンク（３１）へ戻され、第２パイロツト弁（１００）の
ボート（１０１）をポペット（１０２）が開き、第２弁
体（９０）の背圧室（９２）のパイロット圧油がタンク
（３１）に戻され、同様に高圧の作動油によりスプリン
グ（９３）に抗してポペット（９１）か後退し、ボー）
　（９４）が開かれる。When lowering, the first on-off valve (62) is closed and the second on-off valve (66) is opened. When the first on-off valve (62) is closed, the low-pressure control oil is guided to the back pressure chamber (86) of the spool (83) of the first pilot valve (80), and the spool (83)
When the boat (81) moves forward, the poppet (82) opens, and the pilot pressure oil in the back pressure chamber (42) of the first valve body (40) returns to the tank (31) through the back pressure chamber (84). , the poppet (4) is pushed against the spring (43) by high-pressure hydraulic oil.
1) or retreats, and Bow)-(44) is opened. When the second on-off valve (66) is opened, the control oil is returned from the boat (67) to the tank (31), the poppet (102) opens the boat (101) of the second pilot valve (100), and the second valve The pilot pressure oil in the back pressure chamber (92) of the body (90) is returned to the tank (31), and the poppet (91) also retreats against the spring (93) due to the high pressure hydraulic oil, causing the bow)
(94) is opened.

このように第１及び第２の両弁体（４０）、　（９０）
が開かれているので、高圧の作動油は逆止弁（３６）上
流側の第２弁体（９０）からタンク（３１）へ戻され、
且つ単動型シリンダ（１０）の油室（１４）内の油は逆
止弁（３６）下流側の第１弁体（４０）からタンク（３
１）へ戻され、これによりリフトアーム（５）、リフト
ロッド（６）等を介して作業機（２）が下降する。In this way, both the first and second valve bodies (40), (90)
is open, high-pressure hydraulic oil is returned to the tank (31) from the second valve body (90) on the upstream side of the check valve (36).
In addition, the oil in the oil chamber (14) of the single-acting cylinder (10) is transferred from the first valve body (40) downstream of the check valve (36) to the tank (3).
1), thereby lowering the working machine (2) via the lift arm (5), lift rod (6), etc.

高さ位置を維持する場合は、第１及び第２の両開閉弁（
６２）　、　（６６）を開く。上述のように第２開閉弁
（６６）の開により第２弁体（９０）が開いて高圧の作
動油は逆止弁（３６）上流側の第２弁体（９０）からタ
ンク（３１）へ戻されるが、第１開閉弁（６２）の開に
より第１弁体（４０）が閉じて単動型シリンダ（１０）
の油室（１４）内の油は逆止弁（３６）にてリークを阻
止されるので、作業機（２）の高さ位置は維持される。When maintaining the height position, the first and second on-off valves (
62), open (66). As mentioned above, when the second on-off valve (66) opens, the second valve body (90) opens, and the high-pressure hydraulic oil is transferred from the second valve body (90) upstream of the check valve (36) to the tank (31). However, when the first on-off valve (62) opens, the first valve body (40) closes and the single-acting cylinder (10)
Since the oil in the oil chamber (14) is prevented from leaking by the check valve (36), the height position of the work implement (2) is maintained.

そして作業１１１（２）の水平制御は複動型シリンダ（
２０）を伸縮させることにより行われ、先ず伸ばす場合
は、右側の第１開閉弁（７２）を開き、第２開閉弁（７
６）を閉じる。第１開閉弁（７２）の開により制御油は
ボート（７３）からタンク（３１）へ戻され、方向切換
弁（５０）の左側の背圧室（５２）から油が抜かれる。The horizontal control of work 111(2) is performed using a double-acting cylinder (
20), and when extending it first, open the first on-off valve (72) on the right side, and then open the second on-off valve (72).
6) Close. By opening the first on-off valve (72), the control oil is returned from the boat (73) to the tank (31), and the oil is removed from the back pressure chamber (52) on the left side of the directional control valve (50).

また第２開閉弁（７６）の閉により低圧の制御油か方向
切換弁（５０）の右側の背圧室（５３）に導かれ、左側
のスプリング（５４）に抗するスプール（５１）の図示
位置からの左動で供給ボート（５８）から作動油か右側
のランド（５６）、油路（１２２）　、給排ボー）−（
２２）を通って複動型シリンダ（２０）の上方の油室（
２５）に送り込まれ、下方の油室（２４）の油はパイプ
（４２１）からスプール弁（３２１）て左方向に押して
開にしたチェック弁（２２１）を通り、油路（１２１）
から左側のランド（５５）を通ってタンク（３１）へ戻
される。In addition, when the second on-off valve (76) is closed, low-pressure control oil is guided to the back pressure chamber (53) on the right side of the directional control valve (50), and the spool (51) resists the spring (54) on the left side. By moving to the left from the position, hydraulic oil is transferred from the supply boat (58) to the land (56) on the right side, oil passage (122), supply/discharge boat) - (
22) and the upper oil chamber (20) of the double-acting cylinder (20).
25), and the oil in the lower oil chamber (24) passes from the pipe (421) through the spool valve (321) and the check valve (221), which is pushed open to the left, to the oil path (121).
From there, it passes through the left land (55) and returns to the tank (31).

従って複動型シリンダ（２０）を備えた方のリフトロッ
ト（６）が伸びて作業機（２）の地面に対する姿勢を水
平に調節することが可能になる。Therefore, the lift rod (6) equipped with the double-acting cylinder (20) extends, making it possible to horizontally adjust the attitude of the working machine (2) with respect to the ground.

縮める場合は、逆に第１開閉弁（７２）を閉し、第２開
閉弁（７６）を開く。第２開閉弁（７６）の開で制御油
はボート（７７）からタンク（３１）へ戻され、方向切
換弁（５０）の右側の背圧室（５３）から油が抜かれ、
第１開閉弁（７２）の閉で制御油が左側の背圧室（５２
）に導かれるのて、そのスプリング（５４）の付勢と併
せてスプール（５１）が図示位置から右動し、作動油は
左側のランド（５５）、油路（１２１）　、給排ボート
（２１）を通り、チェック弁（２２１）を右方向へ押し
て複動型シリンダ（２０）の下方の油室（２４）に送り
込まれ、上方の油室（２５）の油は給排ボート（２２）
、油路（１２２）　、右側のランド（５６）を通ってタ
ンク（３１）へ戻される。これにより複動型シリンダ（
２０）は縮む。When retracting, conversely, close the first on-off valve (72) and open the second on-off valve (76). When the second on-off valve (76) is opened, the control oil is returned from the boat (77) to the tank (31), and the oil is removed from the back pressure chamber (53) on the right side of the directional control valve (50).
When the first on-off valve (72) is closed, the control oil flows into the left back pressure chamber (52).
), the spool (51) moves to the right from the position shown in the figure in conjunction with the bias of the spring (54), and the hydraulic oil flows through the land (55) on the left, the oil passage (121), and the supply/discharge boat ( 21), the check valve (221) is pushed to the right and the oil is sent to the lower oil chamber (24) of the double-acting cylinder (20), and the oil in the upper oil chamber (25) is sent to the supply/discharge boat (22).
, oil passage (122), and is returned to the tank (31) through the right land (56). This allows the double-acting cylinder (
20) will shrink.

長さ状態を維持する場合は、第１及び第２の両開閉弁（
７２）、（７６）を閉じる。上述のように両開閉弁（７
２）　、（７６）の閉により方向切換弁（５０）の左右
の背圧室（５２）　、　（５３）にはともに制御油が導
かれ、スプール（５１）は図示中立位置に保たれて左右
のランド（５５）、（５６）か閉じられるので、複動型
シリンダ（２０）の上下の両袖室（２４）　、　（２５
）からの油のリークは両ランド（５５）　、　（５６）
により阻止される。これにより複動型シリンダ（２０）
の長さ状態が維持され、また作動油はスプール（５１）
内の油路（５７）を通ってボート（５９）、（５９）か
らタンク（３１）へ戻される。また第１及び第２の両開
閉弁（７２）、（７６）を開いても、スプール（５１）
は中立位置に保たれる。When maintaining the length state, both the first and second on-off valves (
72) and (76) are closed. As mentioned above, double open/close valve (7
2) By closing , (76), the control oil is guided to both the left and right back pressure chambers (52) and (53) of the directional control valve (50), and the spool (51) is kept at the neutral position shown in the illustration and the left and right back pressure chambers (52) and (53) are guided. Since the lands (55) and (56) are closed, both upper and lower sleeve chambers (24) and (25) of the double-acting cylinder (20) are closed.
) oil leaks from both lands (55) and (56)
is prevented by This allows the double-acting cylinder (20)
The length condition of is maintained, and the hydraulic oil is supplied to the spool (51).
The water is returned from the boats (59), (59) to the tank (31) through the oil passage (57) inside. Also, even if both the first and second on-off valves (72) and (76) are opened, the spool (51)
is kept in a neutral position.

以上の実施例ではパイロット弁を別体のポペットとスプ
ールで構成したが、一体でも良く、制御油圧を別構造の
弁体の背圧室に直接溝いたり、手動式等の開閉弁を採用
しても良い。また作業機は他の接地作業機ても良く、更
に油圧シリンダも作業機操作用のものに限られるもので
もない。In the above embodiments, the pilot valve was composed of a separate poppet and spool, but it could also be integrated, or the control hydraulic pressure could be channeled directly into the back pressure chamber of a separate valve body, or a manual open/close valve could be used. Also good. Further, the work machine may be any other ground-based work machine, and the hydraulic cylinder is not limited to one for operating the work machine.

（発明の効果） 以上のように本発明によれば、ポンプから油圧シリンダ
への作動油路に設けられる逆止弁の上下流の各弁体の背
圧室へのパイロット圧油を別のポペットとスプールから
成るパイロット弁でそれぞれ制御し、この各パイロット
弁をそのスプール側背圧室に別系統の低圧油を導いてそ
れぞれ開閉弁で制御するようにしたため、開閉弁の小型
小容量化を達成できるとともに、各々の弁体やパイロッ
ト弁が小型化され、ひいては油圧制御ユニットを小型化
、軽量化でき、シール対策の容易化をも達成でき、また
絞り弁により弁体の開閉速度の調整も行うことかできる
。(Effects of the Invention) As described above, according to the present invention, the pilot pressure oil is supplied to the back pressure chamber of each valve body upstream and downstream of the check valve provided in the hydraulic oil path from the pump to the hydraulic cylinder using another poppet. Each pilot valve is controlled by a pilot valve consisting of a spool and a spool, and each pilot valve is controlled by an on-off valve by guiding low-pressure oil from a separate system to its spool-side back pressure chamber, resulting in a smaller and smaller capacity on-off valve. At the same time, each valve body and pilot valve are made smaller, which in turn allows the hydraulic control unit to be made smaller and lighter, making it easier to take measures for sealing.Also, the opening and closing speed of the valve body can be adjusted using a throttle valve. I can do it.

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

第１図はトラクタの概略側面図、第２図は作業機の支持
機構部の概略斜視図、第３図は油圧制御ユニット部の平
面図、第４図は油圧制御の回路構成図である。 尚、図面中、（１）はトラクタ、（２）は作業機、（５
）はリフトアーム、（６）はリフトロッド、（１０）は
昇降用の油圧シリンダ、（２０）は水平制御用の油圧シ
リンダ、（３１）はタンク、（３２）はポンプ、（３３
）は分流弁、（３６）は逆止弁、（３８）は減圧弁、（
４０）　。 （９０）は弁体、（５０）は方向切換弁、（６１）、　
（６５）、（７１）　、（７５）は絞り弁、（６２）　
、（６６）　、（７２）　、（７６）は開閉弁、（８０
）、（１００）はパイロット弁、（１１０）　、（１２
０）は作動油路、（１３０）は制御油路、（１５０）は
油圧制御ユニット、（Ａ）、（Ｂ）、（Ｃ）は油作動装
置である。FIG. 1 is a schematic side view of the tractor, FIG. 2 is a schematic perspective view of the support mechanism of the working machine, FIG. 3 is a plan view of the hydraulic control unit, and FIG. 4 is a circuit diagram of the hydraulic control. In the drawings, (1) is a tractor, (2) is a working machine, and (5 is
) is a lift arm, (6) is a lift rod, (10) is a hydraulic cylinder for lifting, (20) is a hydraulic cylinder for horizontal control, (31) is a tank, (32) is a pump, (33) is a hydraulic cylinder for horizontal control, (31) is a tank, (32) is a pump,
) is a diversion valve, (36) is a check valve, (38) is a pressure reducing valve, (
40). (90) is a valve body, (50) is a directional control valve, (61),
(65), (71), (75) are throttle valves, (62)
, (66), (72), (76) are on-off valves, (80
), (100) are pilot valves, (110), (12
0) is a hydraulic oil passage, (130) is a control oil passage, (150) is a hydraulic control unit, and (A), (B), and (C) are oil hydraulic devices.

Claims (1)

【特許請求の範囲】 　ポンプから油圧シリンダへの作動油路に逆止弁とその
下流側の第１弁体及び上流側の第２弁体とを設け、 該各弁体の背圧室にはパイロット圧油を導くパイロット
油路をそれぞれ接続し、 該各パイロット油路にはポペットとスプールを同軸上に
配置して成るパイロット弁をそれぞれ設け、 該各パイロット弁のスプール側背圧室にはポンプから前
記作動油路の作動油圧より低圧の制御油圧を導く制御油
路をそれぞれ接続し、 該各制御油路には前記各パイロット弁のスプール側背圧
室へ制御油圧を給排するための開閉弁を絞り弁を介して
それぞれ設けたこと、 を特徴とする油圧シリンダの油圧制御装置。[Scope of Claims] A check valve, a first valve body on the downstream side thereof, and a second valve body on the upstream side thereof are provided in the hydraulic oil path from the pump to the hydraulic cylinder, and a back pressure chamber of each valve body includes Pilot oil passages for guiding pilot pressure oil are connected to each other, each pilot oil passage is provided with a pilot valve consisting of a poppet and a spool coaxially arranged, and a back pressure chamber on the spool side of each pilot valve is provided with a pump. A control oil passage is connected from each of the hydraulic oil passages to introduce a control oil pressure lower than the working oil pressure of the hydraulic oil passage, and each of the control oil passages has an opening/closing valve for supplying and discharging the control oil pressure to the spool side back pressure chamber of each of the pilot valves. A hydraulic control device for a hydraulic cylinder, characterized in that the valves are each provided via a throttle valve.