JPH0665602U - Cylinder control circuit in construction machinery - Google Patents
Cylinder control circuit in construction machineryInfo
- Publication number
- JPH0665602U JPH0665602U JP1205393U JP1205393U JPH0665602U JP H0665602 U JPH0665602 U JP H0665602U JP 1205393 U JP1205393 U JP 1205393U JP 1205393 U JP1205393 U JP 1205393U JP H0665602 U JPH0665602 U JP H0665602U
- Authority
- JP
- Japan
- Prior art keywords
- pressure
- cylinder
- bottom side
- side line
- boom
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
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Links
Landscapes
- Operation Control Of Excavators (AREA)
- Fluid-Pressure Circuits (AREA)
Abstract
(57)【要約】
【目的】 ブ−ムを油圧シリンダで直接駆動する油圧シ
ョベル等の建設機械において、作業能率の向上を目指し
てシリンダの作動速度を上げていった場合、作動停止後
にその慣性力と作動油の圧縮性の為に、シリンダが僅か
に伸縮を繰り返す。この為精度が要求される作業の能率
を妨げるという不具合を生ずるが、本考案はこの問題を
解消することを目的とする。
【構成】 外部パイロット信号圧力で絞り開口及び設定
圧力が変化する安全弁一体形ネガコン可変絞り３を有
し、制御弁切換用パイロット圧力を感知する圧力スイッ
チ４及びシリンダ１のボトム側圧力を感知する圧力セン
サ−５を設け、これらの信号をもとにポンプ吐出ライン
６とシリンダボトム側ライン７及びシリンダボトム側ラ
イン７とロッド側ライン９を夫々短絡する電磁切換弁１
０及び８、前記安全弁一体形ネガコン可変絞り３に信号
圧を与える電磁切換弁１２を制御するコントロ−ラ１１
から成り、ブ−ムの操作量以上に作用することなくシリ
ンダの伸縮を素早く収束するようにした。
(57) [Abstract] [Purpose] In a construction machine such as a hydraulic excavator that directly drives a boom with a hydraulic cylinder, when the cylinder operating speed is increased to improve work efficiency, the inertia The cylinder repeatedly expands and contracts slightly due to the force and compressibility of the hydraulic oil. For this reason, there arises a problem that the efficiency of the work requiring precision is hindered, but the present invention aims to solve this problem. [Construction] A safety valve integrated negative control variable throttle 3 whose throttle opening and set pressure are changed by an external pilot signal pressure is provided, and a pressure switch 4 for sensing a control valve switching pilot pressure and a pressure for sensing a bottom side pressure of the cylinder 1 are provided. An electromagnetic switching valve 1 which is provided with a sensor 5 and short-circuits the pump discharge line 6 and the cylinder bottom side line 7 and the cylinder bottom side line 7 and the rod side line 9 based on these signals.
0 and 8, a controller 11 for controlling an electromagnetic switching valve 12 for applying a signal pressure to the safety valve integrated negative control variable throttle 3.
The expansion and contraction of the cylinder can be quickly converged without affecting the operation amount of the boom or more.
Description
【０００１】[0001]
本考案は油圧ショベル等建設機械における油圧シリンダの制御回路に関するも のである。 The present invention relates to a control circuit for a hydraulic cylinder in a construction machine such as a hydraulic excavator.
【０００２】[0002]
油圧ショベル等の油圧で駆動される建設機械の油圧源となる可変容量ポンプは ネガティブコントロ−ル（以下ネガコンという）と呼ばれる制御により操作中立 時の省エネを行なっている場合が多い。このため操作中立状態のポンプ吐出油は 最終的に制御弁ａのポンプＰからタンクＴ（以下Ｐ−Ｔという）への開口の下流 にあるネガコン用絞り（ネガコン絞り）ｂを通りタンクＴに戻る（図４）。ここ でネガコン絞りｂは例えば図５に示す如く安全弁と一体構造の場合が多い。従っ てネガコン絞りｂの上流には圧力が発生し、この圧力によりポンプ吐出量は最小 に保たれ省エネを図っている。 Variable displacement pumps, which are hydraulic power sources for construction machinery driven by hydraulic pressure such as hydraulic excavators, often use a control called a negative control (hereinafter referred to as a negative control) to save energy during operation neutrality. Therefore, the pump discharge oil in the operation neutral state finally returns to the tank T through the negative control throttle (negative control throttle) b downstream of the opening from the pump P of the control valve a to the tank T (hereinafter referred to as PT). (Fig. 4). Here, the negative control throttle b is often integrated with a safety valve as shown in FIG. 5, for example. Therefore, pressure is generated upstream of the negative control throttle b, and the pump discharge amount is kept to a minimum by this pressure to save energy.
【０００３】 ところで各アクチュエ−タの作動速度がさほど速くなかった従来機では、作動 停止時の慣性力があまり大きくならなかったので、本提案が解決しようとする不 具合がさほど目立たなかったのでその為の対策は考慮しなかった。ところが最近 の油圧ショベル等の建設機械は、作業能率の向上を目指して各アクチュエ−タの 作動速度を向上させる傾向にあり、その為慣性の大きいブ−ム駆動シリンダがそ の作動停止後、僅かに伸縮を繰り返す現象が顕著になりこれが問題となっている 。By the way, in the conventional machine in which the actuating speed of each actuator was not so high, the inertial force at the time of the operation stop did not become so large, so the problem to be solved by the present proposal was not so noticeable. I did not consider the measures for it. However, recent construction machines such as hydraulic excavators tend to increase the operating speed of each actuator with the aim of improving work efficiency. The phenomenon of repeated expansion and contraction becomes noticeable, which is a problem.
【０００４】 因みに、容器の容積変化に伴なう容器内の圧力変化は次式で表わされる。 △Ｐ＝−△Ｖ／β×Ｖ ・・・（１） △Ｐ：圧力変化量 β：圧縮率 Ｖ：容器の容積 △Ｖ：容積変化量 ここで、理論上作動油の圧縮率βは圧力とは無関係に一定であり、かつ非常に小 さな値であるが、実際は僅かながら気泡が混入し理論値よりも大きな値となる。 又圧力とは反比例の関係になる。Incidentally, the change in pressure inside the container due to the change in the volume of the container is expressed by the following equation. ΔP = −ΔV / β × V (1) ΔP: Pressure change amount β: Compression ratio V: Container volume ΔV: Volume change amount Here, theoretically, the compression ratio β of the hydraulic fluid is the pressure. It is a constant value regardless of, and is a very small value, but in reality it is slightly larger than the theoretical value due to the inclusion of bubbles. Also, it is inversely proportional to the pressure.
【０００５】 従来現象について図６を参照して説明する。 操作中立で（図６のの位置参照） シリンダのロッド側は無負荷状態、シリンダのボトム側にはブ−ム保持圧が作 用する。 ブ−ム下げ操作時（図６のの位置参照） ロッド側は自由落下状態の為ほぼ無負荷、ボトム側は速度制御圧（＜保持圧） が作用する。The conventional phenomenon will be described with reference to FIG. With the operation neutral (see the position in Fig. 6), the rod side of the cylinder is unloaded, and the bottom side of the cylinder is used with the boom holding pressure. At the time of boom lowering operation (see position in Fig. 6) The rod side is in a free fall state, so there is almost no load, and the bottom side receives speed control pressure (<holding pressure).
【０００６】 −１ 操作停止後（図６の−１の位置参照） ブ−ムは慣性力により更に降下しようとする。この時ブ−ムの動きを止める十 分な力（圧力）がボトム側にない為ブ−ムは降下する。これに伴ない、 (ａ)ボトム側の容積が減少し圧力が増加する。・・・（１）式参照 この圧力（反力）がブ−ムの慣性力と等しくなるとブ−ムは止まる。 (ｂ)ロッド側はシリンダの縮み（容積の増加）に比例して圧力が低下する（操 作停止直後はもともと無負荷状態）。・・・（１）式参照 −２ ブ−ムが一旦止まった状態で（図６の−２の状態） ボトム側には保持圧以上の圧力が蓄圧されているので、これによりブ−ムは上 昇しようとする。このときロッド側にブ−ムを押える力（圧力）がない為ブ−ム は上昇する。これに伴ない、 (ａ)ボトム側の容積が増加し圧力が減少する。この圧力が中立時の保持圧に達 しても、ブ−ムはその慣性力で更に上昇し圧力が減少する。 (ｂ)ロッド側はシリンダの伸び（容積の減少）に反比例して圧力が上昇する。 この圧力（力）がブ−ムの慣性力と等しくなると停止する。 −３ ブ−ムが再度一旦止まった状態で（図６の−３の状態） ボトム側の圧力が保持圧以下になっているので、ブ−ムを支えきれずシリンダ が縮み（容積の増加）、ブ−ムが降下する。これに伴ないボトム側の圧力が中立 時の保持圧まで上昇しても・・・以下−１以降の繰り返しでシリンダの伸縮を 続け、エネルギ−ロスに伴なって収束する。 ブ−ム上げ操作停止後も同様の現象によりシリンダが伸縮・収束する。−1 After the operation is stopped (see the position −1 in FIG. 6), the boom tries to further descend due to inertial force. At this time, since there is not enough force (pressure) to stop the movement of the boom on the bottom side, the boom drops. Along with this, (a) the volume on the bottom side decreases and the pressure increases. (See formula (1)) When this pressure (reaction force) becomes equal to the inertial force of the boom, the boom stops. (b) On the rod side, the pressure decreases in proportion to the contraction of the cylinder (increase in volume) (there is no load after the operation was stopped). (Refer to formula (1)) -2 When the boom is stopped (state -2 in Fig. 6) Since the pressure higher than the holding pressure is accumulated on the bottom side, the boom is I try to go up. At this time, since there is no force (pressure) to push the boom on the rod side, the boom rises. Along with this, (a) the volume on the bottom side increases and the pressure decreases. Even if this pressure reaches the holding pressure at neutral, the boom further increases due to its inertial force and the pressure decreases. (b) On the rod side, the pressure rises in inverse proportion to the cylinder extension (volume reduction). It stops when this pressure (force) becomes equal to the inertial force of the boom. -3 With the boom stopped once again (state -3 in Fig. 6) Since the pressure on the bottom side is below the holding pressure, the boom cannot be supported and the cylinder contracts (increases in volume). , The boom descends. As a result, even if the pressure on the bottom side rises to the holding pressure at the time of neutrality ... The expansion and contraction of the cylinder continues after -1 and thereafter, and it converges with energy loss. Even after the boom raising operation is stopped, the cylinder expands and contracts due to the same phenomenon.
【０００７】[0007]
ブ−ムを油圧シリンダで直接駆動する油圧ショベル等の建設機械において、作 業能率の向上を目指してシリンダの作動速度を上げていった場合、作動停止後に その慣性力と作動油の圧縮性の為に、シリンダが僅かに伸縮を繰り返す。この為 精度が要求される作業の能率を妨げるという不具合を生ずるが、本考案はこの問 題を解消することを目的とする。 In a construction machine such as a hydraulic excavator that directly drives a boom with a hydraulic cylinder, if the operating speed of the cylinder is increased with the aim of improving work efficiency, the inertia force and the compressibility of hydraulic oil after the operation is stopped Therefore, the cylinder slightly expands and contracts repeatedly. For this reason, there is a problem that the efficiency of the work that requires precision is hindered, but the present invention aims to solve this problem.
【０００８】[0008]
外部パイロット信号圧力で絞り開口及び設定圧力が変化する安全弁一体形ネガ コン可変絞り３を有し、制御弁切換用パイロット圧力を感知する圧力スイッチ４ 及びシリンダ１のボトム側圧力を感知する圧力センサ−５を設け、これらの信号 をもとにポンプ吐出ライン６とシリンダボトム側ライン７及びシリンダボトム側 ライン７とロッド側ライン９を夫々短絡する電磁切換弁１０及び８、前記安全弁 一体形ネガコン可変絞り３に信号圧を与える電磁切換弁１２とを制御するコント ロ−ラ１１から成り、ブ−ム２の操作量以上に作用することなくシリンダの伸縮 を素早く収束するようにした。 又電気−油圧回路のシリンダのボトム側ライン７とロッド側ライン９を短絡す る電磁切換弁８に代えて、シリンダボトム側ライン７とタンクＴを短絡する電磁 切換弁を設けた。 A pressure switch 4 for detecting the control valve switching pilot pressure and a pressure sensor for detecting the pressure on the bottom side of the cylinder 1, which has a safety valve integrated negative control variable throttle 3 whose throttle opening and set pressure change with the external pilot signal pressure. 5 is provided, and based on these signals, electromagnetic switching valves 10 and 8 for short-circuiting the pump discharge line 6, the cylinder bottom side line 7, the cylinder bottom side line 7 and the rod side line 9, respectively, the safety valve integrated negative control variable throttle 3 is composed of a controller 11 for controlling an electromagnetic switching valve 12 which gives a signal pressure to the cylinder 3, so that the expansion and contraction of the cylinder can be quickly converged without affecting the operation amount of the boom 2 or more. Further, instead of the solenoid switching valve 8 that short-circuits the bottom line 7 and the rod line 9 of the cylinder of the electro-hydraulic circuit, an electromagnetic switching valve that short-circuits the cylinder bottom line 7 and the tank T is provided.
【０００９】[0009]
図１に基いて説明する。図１は油圧ポンプＰからの圧油を油圧パイロット式制 御弁ａを介してシリンダ１のボトム1a及びロッド1b側に送り、ブ−ム２を駆動す る油圧回路である。３は図２に示す如く外部パイロット信号圧により、その絞り 3aの開口と安全弁3bの設定圧力を変更することが可能な安全弁一体形ネガコン可 変絞りである。４は制御弁切換用パイロット圧力を感知する圧力スイッチ、５は シリンダのボトム1a側の圧力を感知する圧力センサ−である。１０はポンプ吐出 ライン６とシリンダボトム側ライン７を短絡する電磁切換弁、８はシリンダボト ム側ライン７とロッド側ライン９を短絡する電磁切換弁である。１２は安全弁一 体形ネガコン可変絞り３に信号圧を与える電磁切換弁、１１は電磁切換弁８，１ ０，１２を制御するコントロ−ラである。 A description will be given based on FIG. FIG. 1 shows a hydraulic circuit for driving the boom 2 by sending pressure oil from the hydraulic pump P to the bottom 1a and rod 1b sides of the cylinder 1 via a hydraulic pilot type control valve a. Reference numeral 3 denotes a safety valve integrated type negative control variable throttle capable of changing the opening of the throttle 3a and the set pressure of the safety valve 3b by the external pilot signal pressure as shown in FIG. Reference numeral 4 is a pressure switch for detecting the control valve switching pilot pressure, and 5 is a pressure sensor for detecting the pressure on the bottom 1a side of the cylinder. Reference numeral 10 is an electromagnetic switching valve that short-circuits the pump discharge line 6 and the cylinder bottom side line 7, and 8 is an electromagnetic switching valve that short-circuits the cylinder bottom side line 7 and the rod side line 9. Reference numeral 12 is an electromagnetic switching valve that applies a signal pressure to the safety valve integrated negative control variable throttle 3, and 11 is a controller that controls the electromagnetic switching valves 8, 10 and 12.
【００１０】 図３にもとずいてブ−ム下げ停止について説明する。操作「オン」から「オフ」 への切換途中からボトム1a側にサ−ジ圧力が発生する。この後完全に操作「オフ」 になったことを圧力スイッチ４で感知する。 ボトム側圧力が急激に上昇していることを圧力センサ−５で感知すると、そ の後ボトム側圧力が急激に降下するまでの間、シリンダロッド側ライン９とボト ム側ライン７を短絡する電磁切換弁８を「オン」し、ボトム側の圧油をロッド側 あるいはタンクＴに逃がせばボトム側の圧力上昇を抑えることが出来、この後ブ −ム２を押し上げる力（圧力）が弱まり、シリンダ１の伸縮が早く収束する。 ところがこの時単純にボトム側の圧油をロッド側に逃がすだけでは、ブ−ム２ が操作量以上に降下することになるので、の動作と平行して・・・The stop of the boom lowering will be described with reference to FIG. Surge pressure is generated on the bottom 1a side while the operation is switching from "ON" to "OFF". After this, the pressure switch 4 senses that the operation is completely "off". When the pressure sensor-5 senses that the bottom side pressure is rising rapidly, an electromagnetic circuit that short-circuits the cylinder rod side line 9 and the bottom side line 7 until the bottom side pressure drops sharply thereafter. If the switching valve 8 is turned on and the bottom side pressure oil is released to the rod side or the tank T, the pressure increase on the bottom side can be suppressed. After that, the force (pressure) for pushing up the boom 2 is weakened, and the cylinder Expansion and contraction of 1 converge quickly. However, at this time, if the pressure oil on the bottom side is simply released to the rod side, the boom 2 will drop more than the operation amount.
【００１１】 ボトム側圧力が急激に降下していることを圧力センサ−５で感知すると、安 全弁一体形ネガコン可変絞り３にパイロット信号を与える電磁切換弁１２を一定 時間「オン」し、ポンプ吐出圧を高めるとともに、ポンプ吐出圧ライン６とシリ ンダボトム側ライン７を短絡する電磁切換弁１０を同様に一定時間「オン」し、 シリンダボトム側に圧油を供給する。 以上の一連の動作によりブ−ムを操作量以上に降下させることなくシリンダの 伸縮を素早く収束させることが出来る。 以上の実施例において、電気−油圧回路のシリンダのボトム側ライン７とロッ ド側ライン９を短絡する電磁切換弁８に代えて、シリンダボトム側ライン７とタ ンクＴを短絡する電磁切換弁を設けてもよい。When the pressure sensor-5 senses that the bottom side pressure is drastically decreasing, the electromagnetic switching valve 12 that supplies a pilot signal to the safety valve integrated negative control variable throttle 3 is turned on for a certain period of time, and the pump is turned on. While increasing the discharge pressure, the electromagnetic switching valve 10 that short-circuits the pump discharge pressure line 6 and the cylinder bottom side line 7 is also turned on for a certain period of time to supply pressure oil to the cylinder bottom side. By the above series of operations, the expansion and contraction of the cylinder can be quickly converged without lowering the boom beyond the operation amount. In the above embodiment, instead of the electromagnetic switching valve 8 that short-circuits the bottom line 7 and the rod line 9 of the cylinder of the electro-hydraulic circuit, an electromagnetic switching valve that short-circuits the cylinder bottom line 7 and the tank T is used. It may be provided.
【００１２】[0012]
外部パイロット信号圧力で絞り開口及び設定圧力が変化する安全弁一体形ネガ コン可変絞り３を有し、制御弁切換用パイロット圧力を感知する圧力スイッチ４ 及びシリンダ１のボトム側圧力を感知する圧力センサ−５を設け、これらの信号 をもとにポンプ吐出ライン６とシリンダボトム側ライン７及びシリンダボトム側 ライン７とロッド側ライン９を夫々短絡する電磁切換弁１０及び８、前記安全弁 一体形ネガコン可変絞り３に信号圧を与える電磁切換弁１２を制御するコントロ −ラ１１で構成したので、ブ−ムの操作量以上に降下又は上昇することなく、シ リンダの伸縮を素早く収束させることが可能となった。かくして精度を要求され る作業を能率よく実施することが可能となった。 A pressure switch 4 for detecting the control valve switching pilot pressure and a pressure sensor for detecting the pressure on the bottom side of the cylinder 1, which has a safety valve integrated negative control variable throttle 3 whose throttle opening and set pressure change with the external pilot signal pressure. 5 is provided, and based on these signals, electromagnetic switching valves 10 and 8 for short-circuiting the pump discharge line 6, the cylinder bottom side line 7, the cylinder bottom side line 7 and the rod side line 9, respectively, the safety valve integrated negative control variable throttle Since it is composed of the controller 11 which controls the electromagnetic switching valve 12 which gives the signal pressure to the motor 3, the expansion and contraction of the cylinder can be quickly converged without lowering or rising more than the operation amount of the boom. It was In this way, it became possible to efficiently perform work that required accuracy.
【図面の簡単な説明】[Brief description of drawings]
【図１】本考案を実施した油圧−電圧回路。FIG. 1 is a hydraulic-voltage circuit embodying the present invention.
【図２】外部パイロット信号圧で絞り開口可変の安全弁
一体型ネガコン絞り。[Fig. 2] A negative control throttle with a built-in safety valve whose throttle opening is variable by external pilot signal pressure.
【図３】本考案の作動説明図。FIG. 3 is an explanatory view of the operation of the present invention.
【図４】公知のシリンダ−油圧制御回路。FIG. 4 Known cylinder-hydraulic control circuit.
【図５】安全弁一体型ネガコン絞り。[Fig. 5] Negative control diaphragm with integrated safety valve.
【図６】公知制御回路の作動説明図。FIG. 6 is an operation explanatory diagram of a known control circuit.
Ｔ タンク Ｐ 油圧ポンプ ａ 制御弁 １ シリンダ 1a ボトム 1b ロッド ２ ブ−ム ３ 安全弁一体型ネガコン可変絞り ４ 圧力スイッチ ５ 圧力センサ− ６ ポンプ吐出ライン ７ シリンダボトム
側ライン ８ 電磁切換弁 ９ ロッド側ライン 10 電磁切換弁 11 コントロ−ラ 12 電磁切換弁T tank P hydraulic pump a control valve 1 cylinder 1a bottom 1b rod 2 boom 3 safety valve integrated negative control variable throttle 4 pressure switch 5 pressure sensor 6 pump discharge line 7 cylinder bottom side line 8 solenoid switching valve 9 rod side line 10 Solenoid selector valve 11 Controller 12 Solenoid selector valve
Claims (2)
設定圧力が変化する安全弁一体形ネガコン可変絞り(３)
を有し、制御弁切換用パイロット圧力を感知する圧力ス
イッチ(４)及びシリンダ(１)のボトム側圧力を感知する
圧力センサ−(５)を設け、これらの信号をもとにポンプ
吐出ライン(６)とシリンダボトム側ライン(７)及びシリ
ンダボトム側ライン(７)とロッド側ライン(９)を夫々短
絡する電磁切換弁(10)及び電磁切換弁(８)、さらに前記
安全弁一体形ネガコン可変絞り(３)に信号圧を与える電
磁切換弁(12)とを制御するコントロ−ラ(11)から成り、
ブ−ム(２)の操作量以上に作用することなくシリンダの
伸縮を素早く収束するようにしたことを特徴とする建設
機械におけるシリンダの制御回路。1. A safety valve integrated negative control variable throttle (3) in which a throttle opening and a set pressure are changed by an external pilot signal pressure.
And a pressure switch (4) for detecting the pilot pressure for switching the control valve and a pressure sensor (5) for detecting the pressure on the bottom side of the cylinder (1) are provided. Based on these signals, the pump discharge line ( 6) and the cylinder bottom side line (7), and the cylinder bottom side line (7) and the rod side line (9) are short-circuited, respectively, and a solenoid switching valve (10) and a solenoid switching valve (8) and the safety valve integrated negative control variable It consists of a controller (11) that controls the electromagnetic switching valve (12) that gives a signal pressure to the throttle (3),
A control circuit for a cylinder in a construction machine, characterized in that expansion and contraction of the cylinder is quickly converged without acting beyond the operation amount of the boom (2).
イン(７)とロッド側ライン(９)を短絡する電磁切換弁
(８)に代えて、シリンダボトム側ライン(７)とタンク
(Ｔ)を短絡する電磁切換弁を設けた請求項１の建設機械
におけるシリンダの制御回路。2. An electromagnetic switching valve for short-circuiting a bottom side line (7) and a rod side line (9) of a cylinder of an electro-hydraulic circuit.
Cylinder bottom line (7) and tank instead of (8)
The control circuit for a cylinder in a construction machine according to claim 1, further comprising an electromagnetic switching valve that short-circuits (T).
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP1205393U JPH0665602U (en) | 1993-02-24 | 1993-02-24 | Cylinder control circuit in construction machinery |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP1205393U JPH0665602U (en) | 1993-02-24 | 1993-02-24 | Cylinder control circuit in construction machinery |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| JPH0665602U true JPH0665602U (en) | 1994-09-16 |
Family
ID=11794864
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP1205393U Pending JPH0665602U (en) | 1993-02-24 | 1993-02-24 | Cylinder control circuit in construction machinery |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPH0665602U (en) |
Cited By (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH09105152A (en) * | 1995-10-11 | 1997-04-22 | Hitachi Constr Mach Co Ltd | Work range limit control device of construction machine |
| JP2016217490A (en) * | 2015-05-22 | 2016-12-22 | ナブテスコ株式会社 | Pressure generating device for control and hydraulic system |
| CN107061423A (en) * | 2017-06-29 | 2017-08-18 | 长沙学院 | A kind of hydraulic cylinder brakes stabilization control device and method |
| CN107061422A (en) * | 2017-06-29 | 2017-08-18 | 长沙学院 | Stabilization control device and method in hydraulic cylinder positioning braking procedure |
| JP2021055800A (en) * | 2019-10-01 | 2021-04-08 | 株式会社クボタ | Hydraulic system of working machine |
-
1993
- 1993-02-24 JP JP1205393U patent/JPH0665602U/en active Pending
Cited By (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH09105152A (en) * | 1995-10-11 | 1997-04-22 | Hitachi Constr Mach Co Ltd | Work range limit control device of construction machine |
| JP2016217490A (en) * | 2015-05-22 | 2016-12-22 | ナブテスコ株式会社 | Pressure generating device for control and hydraulic system |
| CN107061423A (en) * | 2017-06-29 | 2017-08-18 | 长沙学院 | A kind of hydraulic cylinder brakes stabilization control device and method |
| CN107061422A (en) * | 2017-06-29 | 2017-08-18 | 长沙学院 | Stabilization control device and method in hydraulic cylinder positioning braking procedure |
| CN107061422B (en) * | 2017-06-29 | 2018-12-14 | 长沙学院 | Hydraulic cylinder positions the stabilization control device and method in braking process |
| CN107061423B (en) * | 2017-06-29 | 2018-12-25 | 长沙学院 | A kind of hydraulic cylinder braking stabilization control device and method |
| JP2021055800A (en) * | 2019-10-01 | 2021-04-08 | 株式会社クボタ | Hydraulic system of working machine |
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