JP3193616B2 - Direction switching valve controller - Google Patents
Direction switching valve controllerInfo
- Publication number
- JP3193616B2 JP3193616B2 JP03381396A JP3381396A JP3193616B2 JP 3193616 B2 JP3193616 B2 JP 3193616B2 JP 03381396 A JP03381396 A JP 03381396A JP 3381396 A JP3381396 A JP 3381396A JP 3193616 B2 JP3193616 B2 JP 3193616B2
- Authority
- JP
- Japan
- Prior art keywords
- valve
- control
- signal
- lever
- switching valve
- 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.)
- Expired - Fee Related
Links
- 238000012937 correction Methods 0.000 claims description 82
- 230000007935 neutral effect Effects 0.000 claims description 23
- 238000012545 processing Methods 0.000 claims description 20
- 238000000034 method Methods 0.000 claims description 9
- 230000008569 process Effects 0.000 claims description 8
- 230000003111 delayed effect Effects 0.000 claims description 3
- 238000010586 diagram Methods 0.000 description 18
- 230000008859 change Effects 0.000 description 7
- 238000001514 detection method Methods 0.000 description 7
- 230000035939 shock Effects 0.000 description 6
- 238000004519 manufacturing process Methods 0.000 description 4
- 230000007246 mechanism Effects 0.000 description 3
- 238000013459 approach Methods 0.000 description 2
- 238000010276 construction Methods 0.000 description 2
- 238000006073 displacement reaction Methods 0.000 description 2
- 230000009467 reduction Effects 0.000 description 2
- 230000007423 decrease Effects 0.000 description 1
- 230000000994 depressogenic effect Effects 0.000 description 1
- 230000006866 deterioration Effects 0.000 description 1
- 230000006870 function Effects 0.000 description 1
- 239000007769 metal material Substances 0.000 description 1
- 230000000116 mitigating effect Effects 0.000 description 1
- 238000003672 processing method Methods 0.000 description 1
- 230000004044 response Effects 0.000 description 1
- 230000035807 sensation Effects 0.000 description 1
- 238000012546 transfer Methods 0.000 description 1
Landscapes
- Operation Control Of Excavators (AREA)
Description
【０００１】[0001]
【発明の属する技術分野】本発明は操作レバーの操作に
より駆動制御されるアクチュエーターに供給される圧油
の方向と流量を切り替え制御する方向切替弁の切替え動
作制御を行う方向切替弁制御装置の技術分野に属する。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a directional control valve control device for controlling a switching operation of a directional control valve for controlling a direction and a flow rate of pressure oil supplied to an actuator which is driven and controlled by operating an operation lever. Belongs to the field.
【０００２】[0002]
【従来の技術】建設機械、例えば、油圧ショベルは作業
機、旋回体、走行体等の動作機構を具えており、それら
を駆動するアクチュエーターにより上下左右の回動動作
や前後の移動動作が行われる。そして、これらのアクチ
ュエーターは油圧ショベルが具える原動機により駆動さ
れる油圧ポンプから吐出された圧油により駆動される。
油圧ポンプとアクチュエーターを接続する油圧回路中に
それぞれ方向切替弁が配設されていて、それぞれの操作
レバーの操作により各方向切替弁がそれぞれ切り替えら
れることにより、アクチュエーターの作動制御が行われ
るようになっている。2. Description of the Related Art A construction machine, for example, a hydraulic shovel is provided with operating mechanisms such as a work machine, a swing body, a traveling body, and the like, and actuators for driving them perform vertical and horizontal rotation operations and forward and backward movement operations. . These actuators are driven by pressurized oil discharged from a hydraulic pump driven by a prime mover of a hydraulic shovel.
Directional switching valves are provided in a hydraulic circuit connecting the hydraulic pump and the actuator, and the operation of the actuator is controlled by switching each of the directional switching valves by operating each operation lever. ing.
【０００３】ところで、圧油が流れる油圧回路の管路や
アクチュエーター等の回路要素は極めて高い圧力にも耐
えられるように強靱な金属素材により作成されているた
め、高い油圧が付与されても殆ど撓み変形しない。従っ
て、アクチュエーターに急激に圧油が流入したり、アク
チュエーターから急激に圧油が流出したりすると、被駆
動体に大きな衝撃力や振動が加わって、運転者に不快感
を与えたり、油圧回路要素の劣化の進行を早めたりす
る。[0003] Since the circuit elements such as the pipelines and actuators of the hydraulic circuit through which the pressure oil flows are made of a tough metal material so as to withstand extremely high pressure, they are almost bent even when high oil pressure is applied. Does not deform. Therefore, if pressure oil suddenly flows into or out of the actuator, a large impact force or vibration will be applied to the driven body, causing the driver to feel uncomfortable or to disturb the hydraulic circuit element. Or accelerate the progress of deterioration.
【０００４】そこで、このような作業機の起動や停止時
の急操作時等に発生する機械的ショックを防止するため
に、操作レバーを電気レバーで構成し、この電気操作レ
バーから出力された操作信号をマイクロコンピューター
で構成されたコントローラーに導き、コントローラーの
電子制御、例えば、一次遅れ要素等を用いた遅延処理に
より、急操作を緩和した出力信号を得て、この出力信号
を電磁式比例減圧弁で構成された方向切替弁に導いて電
気信号により方向切替弁を切り替え動作させることによ
り、急操作時等に生じる衝撃力や振動を緩和するように
した油圧駆動方式が提案されている。Therefore, in order to prevent a mechanical shock occurring at the time of sudden operation such as starting and stopping of the working machine, the operating lever is constituted by an electric lever, and the operating lever outputted from the electric operating lever is operated. The signal is led to a controller composed of a microcomputer, and an electronic control of the controller, for example, delay processing using a first-order lag element, etc., obtains an output signal in which sudden operation is alleviated. There has been proposed a hydraulic drive system in which an impact signal and a vibration generated at the time of an abrupt operation or the like are reduced by guiding the directional control valve to a directional control valve configured as described above and switching the directional control valve by an electric signal.
【０００５】図８はかかる油圧駆動方式の制御回路の概
略を示すブロック図である。操作レバーの操作量検出装
置１より出力された制御信号ＣＴはコントローラー２に
入力され、そこで一次遅れ要素を用いた遅延処理が施さ
れ、急操作の制御信号ＣＴを緩和した補正信号ＭＤ（Ｍ
Ｄ′）を出力する。補正信号ＭＤ（ＭＤ′）が電磁式比
例減圧弁３（３′）に入力されると、電磁式比例減圧弁
３（３′）は補正信号ＭＤ（ＭＤ′）に応じた開口量で
パイロット油ＰＬを流出させる。電磁式比例減圧弁３
（３′）から流出したパイロット油ＰＬは方向切替弁４
１の操作レバー７の操作方向に対応したパイロット室に
流入し、方向切替弁４１をパイロット油ＰＬの流量に比
例した油圧で切り替えることにより、アクチュエーター
５には電磁式比例減圧弁３（３′）に入力した補正信号
ＭＤ（ＭＤ′）に応じた流量の駆動圧油が流入し、例え
ば、シリンダーが伸長または縮小する。FIG. 8 is a block diagram schematically showing a control circuit of such a hydraulic drive system. The control signal CT output from the operation lever operation amount detection device 1 is input to the controller 2, where a delay process using a first-order delay element is performed, and the correction signal MD (M
D '). When the correction signal MD (MD ') is input to the electromagnetic proportional pressure reducing valve 3 (3'), the electromagnetic proportional pressure reducing valve 3 (3 ') has a pilot oil with an opening amount corresponding to the correction signal MD (MD'). Let the PL flow out. Electromagnetic proportional pressure reducing valve 3
The pilot oil PL flowing out from (3 ') is
By flowing into the pilot chamber corresponding to the operation direction of the first operation lever 7 and switching the direction switching valve 41 with a hydraulic pressure proportional to the flow rate of the pilot oil PL, the actuator 5 is provided with an electromagnetic proportional pressure reducing valve 3 (3 ′). The drive pressure oil flows at a flow rate corresponding to the correction signal MD (MD ') input to the controller, and the cylinder expands or contracts, for example.
【０００６】図９および図１０は操作レバー７を一方向
に等速で操作して、その状態を保持した後、中立位置ま
で戻し操作した時の操作量検出装置１から出力された制
御信号ＣＴ（実線）とコントローラー２から出力された
補正信号ＭＤ（破線）の波形図であり、図９は急戻し操
作、図１０は緩戻し操作した時のものを示している。こ
れらの図に示すように、補正信号ＭＤは減衰する制御信
号ＣＴに追随して指数関数的に減衰する。操作レバー７
が中立位置を越えて反対方向に操作された時には、コン
トローラー２からは電磁式比例減圧弁３′に逆向きに増
大する制御信号ＣＴに追随して指数関数的に増大する補
正信号ＭＤ′が新たに出力され、電磁式比例減圧弁３′
からは補正信号ＭＤ′に従って流量が制御され、方向切
替弁４１の異なる側のパイロット室に流入するパイロッ
ト油ＰＬが流出する。FIGS. 9 and 10 show a control signal CT output from the operation amount detecting device 1 when the operation lever 7 is operated at a constant speed in one direction, and after maintaining the state, the operation lever 7 is returned to the neutral position. (Solid line) and a waveform diagram of the correction signal MD (broken line) output from the controller 2, FIG. 9 shows a case where a quick return operation is performed, and FIG. 10 shows a case where a slow return operation is performed. As shown in these figures, the correction signal MD attenuates exponentially following the attenuating control signal CT. Operation lever 7
Is operated in the opposite direction beyond the neutral position, the controller 2 newly outputs a correction signal MD 'which increases exponentially to the electromagnetic proportional pressure reducing valve 3' following the control signal CT which increases in the opposite direction. Output to the solenoid proportional pressure reducing valve 3 '
After that, the flow rate is controlled according to the correction signal MD ', and the pilot oil PL flowing into the pilot chambers on the different side of the direction switching valve 41 flows out.
【０００７】図１１は操作レバー７を一方向に操作し
て、一定の操作量を保持した後、中立位置を超えて反対
方向に緩やかに操作して、一定の操作量を保持した時の
制御信号ＣＴ（実線）、補正信号ＭＤ，ＭＤ′（破線）
および方向切替弁４１のスプール位置ＳＬ（一点鎖線）
の波形図である。同図に示すように、操作レバー７が順
方向で戻し操作されている間はコントローラー２からは
一方の電磁式比例減圧弁３のみに制御信号ＣＴに追随し
て減衰する補正信号ＭＤが出力されるが、操作レバー７
が中立位置を越えて逆方向まで操作されると、電磁式比
例減圧弁３′にも制御信号ＣＴに追随して増大する補正
信号ＭＤ′が出力される。FIG. 11 shows a control in which the operation lever 7 is operated in one direction to maintain a constant operation amount, and then gradually moved in the opposite direction beyond the neutral position to maintain a constant operation amount. Signal CT (solid line), correction signals MD, MD '(dashed line)
And the spool position SL of the direction switching valve 41 (dashed line)
FIG. As shown in the figure, while the operation lever 7 is being returned in the forward direction, the controller 2 outputs a correction signal MD that attenuates following the control signal CT only to one of the electromagnetic proportional pressure reducing valves 3. Operating lever 7
Is operated beyond the neutral position to the opposite direction, the electromagnetic proportional pressure reducing valve 3 'also outputs a correction signal MD' that increases following the control signal CT.
【０００８】この結果、方向切替弁４１の両側のパイロ
ット室にパイロット油ＰＬが流入し、それらの流量の差
に基づいて方向切替弁４１のスプール位置ＳＬが決まる
ことになる。従って、操作レバー７が中立位置まで戻し
操作された時は、方向切替弁４１のスプール位置ＳＬは
未だ順方向の切替え位置にあり、操作レバー７が中立位
置を越えて逆方向まで操作され、方向切替弁４１の一方
のパイロット室に流入するパイロット油ＰＬと他方のパ
イロット室に流入するパイロット油ＰＬの流量、従っ
て、パイロット圧が等しくなるＰ′点まで至って始めて
方向切替弁４１のスプール位置ＳＬが中立位置まで戻
る。つまり、運転者は操作レバー７を中立位置を越えて
逆方向に操作しているにも拘らず、方向切替弁４１は当
該アクチュエーターを未だ順方向に動かす指令を受けて
いることになる。As a result, the pilot oil PL flows into the pilot chambers on both sides of the direction switching valve 41, and the spool position SL of the direction switching valve 41 is determined based on the difference between the flow rates. Therefore, when the operation lever 7 is operated to return to the neutral position, the spool position SL of the direction switching valve 41 is still in the forward switching position, and the operation lever 7 is operated beyond the neutral position to the reverse direction, and the direction is changed. The flow rate of the pilot oil PL flowing into one pilot chamber of the switching valve 41 and the flow rate of the pilot oil PL flowing into the other pilot chamber, and therefore, the spool position SL of the direction switching valve 41 only reaches the point P 'at which the pilot pressure becomes equal. Return to neutral position. That is, although the driver is operating the operation lever 7 in the reverse direction beyond the neutral position, the direction switching valve 41 has received a command to move the actuator in the forward direction.
【０００９】このように、操作レバー７が中立位置を越
えて逆方向まで操作された時の制御信号ＣＴに一次遅れ
要素を用いた遅延処理を施した補正信号ＭＤ，ＭＤ′に
より電磁式比例減圧弁３，３′をそれぞれ駆動して方向
切替弁４１のスプール位置ＳＬを切り替えさせると、方
向切替弁４１を介して駆動圧油の供給を受けるアクチュ
エーターの動きと運転者の操作感覚とのずれが生じるば
かりでなく、運転者が操作する操作レバー７の操作方向
と当該操作レバー７により操作されるアクチュエーター
の動作方向が逆になる場合があるため、非常に危険であ
った。As described above, when the control lever CT is operated in the opposite direction beyond the neutral position, the control signal CT is subjected to the delay processing using the first-order lag element and the correction signals MD and MD 'are used to perform the electromagnetic proportional pressure reduction. When the spool position SL of the direction switching valve 41 is switched by driving the valves 3 and 3 ′, the movement of the actuator receiving the supply of the driving pressure oil via the direction switching valve 41 and the deviation of the operation feeling of the driver are reduced. Not only that, the operation direction of the operation lever 7 operated by the driver and the operation direction of the actuator operated by the operation lever 7 may be reversed, which is very dangerous.
【００１０】そこで、例えば、特開平２−２５６７２３
号公報には操作レバーが一方向から他方向まで連続して
切り替えられた時に、操作レバーが一方向から中立位置
の不感帯を越えた時点で制御信号に対する一方向の駆動
信号の遅れ補正処理を解除し、操作弁には他方向に切り
替えられた操作レバーから出力される制御信号に遅れ補
正処理を施した信号を送ってスプール位置を切り替えさ
せることにより、操作方向が逆向きに切り替えられた操
作レバーの動きと操作弁を介して駆動圧油の供給を受け
るアクチュエーターの動きを連動させて、操作性の向上
と危険の抑止を図ることができるようにした建設機械の
作業機制御方法の発明が開示されている。Therefore, for example, Japanese Patent Application Laid-Open No. 2-256723
In the Japanese Patent Publication, when the control lever is continuously switched from one direction to the other direction, the delay correction processing of the one-way drive signal with respect to the control signal is released when the control lever crosses the dead zone of the neutral position from one direction. The operation valve is switched to the opposite direction by sending a control signal output from the operation lever switched to the other direction to the operation valve and delaying the spool signal by switching the spool position. The invention discloses a method of controlling a working machine of a construction machine in which operability can be improved and danger can be suppressed by linking the movement of the actuator with the movement of an actuator that receives a supply of driving pressure oil via an operation valve. Have been.
【００１１】[0011]
【発明が解決しようとする課題】上述の従来技術によれ
ば、操作レバーが一方向から他方向まで連続して切り替
えられた時に、操作弁を介して駆動圧油の供給を受ける
アクチュエーターの動きが操作レバーの動きと連動する
ので、運転者の操作感覚とのずれが生じることなく、ア
クチュエーターの暴走による危険を抑止できるが、操作
レバーが一方向から中立位置の不感帯を越えた時点で制
御信号に対する一方向の駆動信号の遅れ補正処理が解除
され、操作弁のスプール位置が直ちに中立位置まで戻さ
れるから、この切替えの際にアクチュエーターは大きな
衝撃を受け、操作性が損なわれると共に運転者に不快感
を与える。遅れ補正処理の時定数を小さくすれば発生す
る衝撃を緩和できるが、逆に急操作時に発生する衝撃を
緩和できなくなる。本発明は従来技術におけるかかる課
題を解決すべく為されたものであり、急操作時に発生す
る衝撃を緩和しながら、操作レバーが一方向から他方向
まで連続して切り替えられた時の運転者の操作感覚との
ずれやアクチュエーターの暴走による危険を抑止できる
方向切替弁制御装置を提供することを目的とする。According to the above-mentioned prior art, when the operation lever is continuously switched from one direction to the other direction, the movement of the actuator which receives the supply of the driving pressure oil via the operation valve is reduced. Since it is linked with the operation of the operation lever, it is possible to suppress the danger caused by the runaway of the actuator without causing a deviation from the driver's operation feeling, but the control signal is applied when the operation lever crosses the dead zone of the neutral position from one direction. Since the delay correction processing of the one-way drive signal is canceled and the spool position of the operation valve is immediately returned to the neutral position, the actuator receives a large impact during this switching, impairing operability and feeling uncomfortable for the driver give. If the time constant of the delay correction process is reduced, the generated shock can be reduced, but the shock generated at the time of sudden operation cannot be reduced. The present invention has been made to solve such a problem in the prior art, and reduces the impact of a driver when the operation lever is continuously switched from one direction to the other direction while alleviating the shock generated at the time of sudden operation. It is an object of the present invention to provide a directional control valve control device capable of suppressing a deviation from an operational feeling and a danger due to a runaway of an actuator.
【００１２】[0012]
【課題を解決するための手段】本発明は上記課題を解決
するために、操作レバーが一方向に操作された後、逆方
向に到るまで操作された時には、操作レバーの操作量を
検知した制御信号を操作レバーの中立位置で分離するこ
となく、一方向から逆方向まで連続した信号として取り
扱った遅れ補正処理により補正信号を演算し、方向切替
弁の切替え動作を行わせる補正信号を方向切替弁のスプ
ールを中立位置とする値で切り替えて、方向切替弁のス
プールを反対方向に駆動するための補正信号としたり、
方向切替弁の切替え動作をその全区間に亘って連続的に
行う弁駆動手段に補正信号を出力して方向切替弁の切替
え動作を連続的に行わせる制御手段を具えたものであ
る。SUMMARY OF THE INVENTION In order to solve the above-mentioned problems, the present invention detects the operation amount of the operation lever when the operation lever is operated in one direction and then operated in the opposite direction. without separating the control signal at the neutral position of the operating lever, it calculates the correction signal by a delay correction process handled as a continuous signal from one direction to the opposite direction, direction switching a correction signal for causing the switching operation of the direction switching valve switching the spool valve in value to the neutral position, the spool of the square direction switching valve or a correction signal for driving the opposition direction,
It is obtained comprising a control means for continuously perform the switching operation of the output to the directional control valve the correction signal to the valve drive means continuously carried out over the entire section of the operation switch of the direction switching valve.
【００１３】[0013]
【発明の実施の形態】図１は本発明の実施の形態の一例
を示す概念図である。従来例と同一または同一と見做せ
る箇所には同一の符号を付し、その重複する説明を省略
する。以下の説明においても同様とする。図において、
４はアクチュエーター５へ供給される駆動圧油の方向と
流量を切り替え制御する油圧制御装置である。油圧制御
装置４は方向切替弁を内蔵しており、補正信号ＭＤが油
圧制御装置４に入力した時、その符号の正負によって補
正信号ＭＤが付与される方向切替弁の制御室の位置が切
り替えられる。FIG. 1 is a conceptual diagram showing an example of an embodiment of the present invention. The same reference numerals are given to portions which are the same as or can be regarded as the same as those in the conventional example, and redundant description will be omitted. The same applies to the following description. In the figure,
Reference numeral 4 denotes a hydraulic control device for switching and controlling the direction and flow rate of the driving pressure oil supplied to the actuator 5. The hydraulic control device 4 has a built-in direction switching valve, and when the correction signal MD is input to the hydraulic control device 4, the position of the control room of the direction switching valve to which the correction signal MD is given is switched according to the sign of the sign. .
【００１４】本発明においても、マイクロコンピュータ
ーで構成されるコントローラー２は電気レバーで構成さ
れた操作レバー７の操作により出力された制御信号ＣＴ
に一次遅れ要素等を用いて遅れ補正処理を施した補正信
号ＭＤを生成して油圧制御装置４に出力するが、補正信
号ＭＤの生成に当たっては操作レバー７の操作量をその
中立位置を起点とした独立した変化量と見ずに、順方向
は正、逆方向は負の連続した変化量として扱う。即ち、
一次遅れ要素：伝達関数ｈ(s) は ｈ(s) ＝１／（Ｕｓ＋１） （Ｕ；時定数） で与えられ、補正信号ＭＤを時分割した時のｎ番目の制
御信号および補正信号をＣＴn およびＭＤn とすると、 ＭＤn ＝ＭＤn 〔１＋Ａ・Ｕ（ＣＴn −ＣＴn-1 ）〕 （Ａは定数） …(1) となる。制御信号ＣＴおよび補正信号ＭＤは正および負
の値を取り得るので、時分割した時のｎ番目の制御信号
ＣＴn および補正信号ＭＤn も正および負の値を取り得
る。Also in the present invention, the controller 2 composed of a microcomputer is a control signal CT output by the operation of an operation lever 7 composed of an electric lever.
A correction signal MD that has been subjected to delay correction processing using a primary delay element or the like is generated and output to the hydraulic control device 4. In generating the correction signal MD, the amount of operation of the operation lever 7 is defined as a starting point based on its neutral position. The forward direction is treated as a positive and the reverse direction is treated as a negative continuous change amount without being regarded as an independent change amount. That is,
First-order delay element: The transfer function h (s) is given by h (s) = 1 / (Us + 1) (U; time constant), and the n-th control signal and the correction signal when the correction signal MD is time-divided are CT and n and MD n, MD n = MD n [1 + a · U (CT n -CT n-1) ] (a is a constant) becomes (1). Control signal CT and the correction signal MD so can take positive and negative values, n-th control signals CT n and the correction signal MD n when divided time also can take positive and negative values.
【００１５】補正信号ＭＤの符号が反転した時の出力先
の切替え動作はコントローラー２が切り替えてそれぞれ
の制御室側に出力するようにしても良いし、補正信号Ｍ
Ｄを油圧制御装置４が受信した後、その符号の正負によ
って出力される制御室の位置を切り替えるようにしても
良い。なお、上述の例では制御信号ＣＴおよび補正信号
ＭＤの原点は操作レバー７の中立位置に取ったが、例え
ば、一方向の最大操作位置に採っても良い。また、遅れ
補正処理は上述の一次遅れ要素を用いた処理の外に二次
遅れ要素との併用、制御信号ＣＴの最大変化量の制限処
理、最大変化速さの補正処理等に依っても良い。The switching operation of the output destination when the sign of the correction signal MD is reversed may be switched by the controller 2 and output to each control room side, or the correction signal M
After the hydraulic control device 4 receives D, the position of the control room that is output according to the sign of the sign may be switched. In the above example, the origin of the control signal CT and the correction signal MD is set at the neutral position of the operation lever 7, but may be set at the maximum operation position in one direction, for example. In addition, the delay correction processing may be based on the use of the second-order delay element in addition to the processing using the first-order delay element described above, processing for limiting the maximum change amount of the control signal CT, correction processing for the maximum change speed, and the like. .
【００１６】図２および図３は操作レバー７を操作した
時の制御信号ＣＴと補正信号ＭＤの変化例を示したもの
であり、図２の例は操作レバー７を順方向に一気に押し
込んだ後、一定の操作量を保ち、次に一気に戻し操作し
て逆方向に押し込んで一定の操作量を保った時の信号波
形、図３の例は操作レバー７を順方向の一定の操作量を
保った後、一定の速さで戻し操作して逆方向に押し込ん
で一定の操作量を保った時の信号波形を示したものであ
る。FIGS. 2 and 3 show examples of changes in the control signal CT and the correction signal MD when the operation lever 7 is operated. FIG. 2 shows an example in which the operation lever 7 is pushed at once in the forward direction. A signal waveform when a constant operation amount is maintained, and then a return operation is performed at once, and then the operation lever 7 is depressed in the reverse direction to maintain a constant operation amount. In the example of FIG. 3, the operation lever 7 is maintained at a constant forward operation amount. After that, a signal waveform is shown when a return operation is performed at a constant speed and the operation is pushed in the opposite direction to maintain a constant operation amount.
【００１７】図２に示すように、制御信号ＣＴが急速に
立ち上がった時は補正信号ＭＤはその変化を緩和するよ
うに指数関数的に立ち上がって一定の制御信号ＣＴの値
に近付く。その後、制御信号ＣＴの急速な立ち下げに追
随してやはり指数関数的に値が低下し、制御信号ＣＴに
やや遅れてＰ点で０になり、さらに負の一定値に保たれ
た制御信号ＣＴの値に指数関数的に近付く。図３に示す
ように、この切替え動作をやや緩やかに行った場合も同
様な動作となる。この際に、正の補正信号ＭＤは油圧制
御装置４が内蔵する方向切替弁の一方の制御室側に、負
の補正信号ＭＤは該方向切替弁の他方の制御室側に出力
される。As shown in FIG. 2, when the control signal CT rises rapidly, the correction signal MD rises exponentially so as to alleviate the change, and approaches a constant value of the control signal CT. Thereafter, the value also decreases exponentially following the rapid fall of the control signal CT, becomes 0 at the point P slightly later than the control signal CT, and furthermore, the control signal CT maintained at a constant negative value Exponentially approach the value of. As shown in FIG. 3, the same operation is performed when the switching operation is performed slightly gently. At this time, the positive correction signal MD is output to one control chamber side of the direction switching valve incorporated in the hydraulic control device 4, and the negative correction signal MD is output to the other control chamber side of the direction switching valve.
【００１８】このように、本発明では制御信号ＣＴが正
の値から負の値に変化した時には、補正信号ＭＤは指数
関数的に０に収斂するのではなく、負の値の制御信号Ｃ
Ｔに指数関数的に追随若しくは収斂するので、操作レバ
ー７が順方向から逆方向に急速に切り替えられた時に、
アクチュエーターを操作レバー７の操作に速やかに、か
つ、滑らかに追随して動作させることができ、アクチュ
エーターの動作が運転者の操作感覚とずれた動きをした
り、操作レバー７の操作方向と反対の向きに動くことが
なく、また、中立位置を越える時にショックを受けるこ
とも無い。As described above, according to the present invention, when the control signal CT changes from a positive value to a negative value, the correction signal MD does not converge exponentially to 0, but the control signal C of a negative value.
Since it follows or converges exponentially to T, when the operating lever 7 is rapidly switched from the forward direction to the reverse direction,
The actuator can be operated promptly and smoothly following the operation of the operation lever 7, and the operation of the actuator may deviate from the driver's operation sensation or may be opposite to the operation direction of the operation lever 7. It does not move in any direction and does not shock when it crosses the neutral position.
【００１９】次に、操作量検出装置１が油圧回路で構成
された本発明の他の実施の形態の例を説明する。図４は
本発明の他の実施の形態を示す概念図である。同図にお
いて、８は操作量検出装置１から流出したパイロット油
の圧力を検出する圧力センサーである。圧力センサー８
で検出されたパイロット圧は制御信号ＣＴとしてコント
ローラー２に入力し、前述のように遅れ補正処理が施さ
れて補正信号ＭＤとして電磁比例減圧弁３に出力され
る。電磁比例減圧弁３はコントローラー２から入力され
た補正信号ＭＤに応じて操作量検出装置１から流出した
パイロット油の圧力を減圧して油圧制御装置４に供給す
る。この例では操作量検出装置１として汎用の操作レバ
ーに接続されるパイロット弁を用いることができる。こ
の例も先に説明した例と同様に動作する。Next, an example of another embodiment of the present invention in which the operation amount detecting device 1 is constituted by a hydraulic circuit will be described. FIG. 4 is a conceptual diagram showing another embodiment of the present invention. In the figure, reference numeral 8 denotes a pressure sensor that detects the pressure of the pilot oil flowing out of the manipulated variable detection device 1. Pressure sensor 8
Is input to the controller 2 as a control signal CT, subjected to delay correction processing as described above, and output to the electromagnetic proportional pressure reducing valve 3 as a correction signal MD. The electromagnetic proportional pressure reducing valve 3 reduces the pressure of the pilot oil flowing out of the operation amount detecting device 1 in accordance with the correction signal MD input from the controller 2 and supplies the reduced pressure to the hydraulic control device 4. In this example, a pilot valve connected to a general-purpose operation lever can be used as the operation amount detection device 1. This example operates similarly to the example described above.
【００２０】油圧制御装置４が内蔵する方向切替弁の駆
動源を電動モーターとすると、本発明の方向切替弁制御
装置の構成を簡単なものにすることができる。図５はか
かる構成の本発明の他の実施の形態を示す概念図であ
る。同図において、４２は油圧制御装置４が内蔵する方
向切替弁を駆動するステッピングモーター等の電動モー
ターと減速歯車で構成される制御駆動部、４３は制御駆
動部４２に駆動され、アクチュエーター５に供給される
圧油の方向と流量を制御する油圧制御部であり、実質的
には線型の切替え動作が可能な方向切替弁と同等であ
る。When the drive source of the directional control valve incorporated in the hydraulic control device 4 is an electric motor, the configuration of the directional control valve control device of the present invention can be simplified. FIG. 5 is a conceptual diagram showing another embodiment of the present invention having such a configuration. In the figure, reference numeral 42 denotes a control drive unit including an electric motor such as a stepping motor for driving a direction switching valve incorporated in the hydraulic control device 4 and a reduction gear, and 43 denotes a control drive unit which is driven by the control drive unit 42 and is supplied to the actuator 5. This is a hydraulic control unit that controls the direction and flow rate of the pressurized oil to be performed, and is substantially equivalent to a direction switching valve capable of performing a linear switching operation.
【００２１】同図に示すように、操作量検出装置１から
出力された制御信号ＣＴにコントローラー２で遅れ補正
処理が施されて出力された補正信号ＭＤは油圧制御装置
４の制御駆動部４２に入力する。制御駆動部４２の例え
ば、ステッピングモーターは油圧制御部４３の方向切替
弁のスプールを駆動して、補正信号ＭＤをスプールの変
移量に変換する。この場合はスプールの変移がモーター
駆動により行われるので、切替え動作を極めて円滑に行
うことができる。次に、本発明をより具体化した実施例
を図面を参照して詳細に説明する。As shown in FIG. 1, the controller 2 performs delay correction processing on the control signal CT output from the operation amount detection device 1 and outputs the correction signal MD output to the control drive unit 42 of the hydraulic control device 4. input. For example, the stepping motor of the control drive unit 42 drives the spool of the direction switching valve of the hydraulic control unit 43 to convert the correction signal MD into a displacement of the spool. In this case, since the displacement of the spool is performed by driving the motor, the switching operation can be performed extremely smoothly. Next, embodiments of the present invention will be described in detail with reference to the drawings.
【００２２】[0022]
【実施例】図６は図１に示した実施の形態を具体化した
実施例に係る方向切替弁制御回路図である。同図におい
て、１０はパイロット油圧ポンプ、１１は所定圧以上の
パイロット圧で放圧する放圧弁、１２は油タンク、４１
はアクチュエーターに供給される駆動圧油を切り替え制
御する電磁式の方向切替弁である。本実施例では操作量
検出装置１は操作レバー７の操作量を電流値に変換する
ポテンショメーターで構成されている。FIG. 6 is a circuit diagram of a directional control valve according to an embodiment that embodies the embodiment shown in FIG. In the figure, reference numeral 10 denotes a pilot hydraulic pump, 11 denotes a pressure relief valve for releasing pressure with a pilot pressure equal to or higher than a predetermined pressure, 12 denotes an oil tank, 41
Is an electromagnetic directional switching valve for switching and controlling the driving pressure oil supplied to the actuator. In this embodiment, the operation amount detection device 1 is configured by a potentiometer that converts the operation amount of the operation lever 7 into a current value.
【００２３】コントローラー２は操作レバー７の操作量
に応じた制御信号ＣＴに上述の遅れ補正処理を施して電
磁式比例減圧弁３，３′に補正信号ＭＤを出力する。Ｍ
Ｄ＞０の時、正の補正信号ＭＤが電磁式比例減圧弁３
に、ＣＴ＜０の時、負の補正信号ＭＤが電磁式比例減圧
弁３′に出力される。電磁式比例減圧弁３，３′はそれ
ぞれ補正信号ＭＤが印加されると、それらの信号電圧の
絶対値に応じて弁が開口し、下流側に信号電圧に比例し
たパイロット圧を発生させる。The controller 2 performs the above-described delay correction processing on the control signal CT corresponding to the operation amount of the operation lever 7, and outputs a correction signal MD to the electromagnetic proportional pressure reducing valves 3, 3 '. M
When D> 0, the positive correction signal MD outputs the electromagnetic proportional pressure reducing valve 3
When CT <0, a negative correction signal MD is output to the electromagnetic proportional pressure reducing valve 3 '. When the correction signal MD is applied to each of the electromagnetic proportional pressure reducing valves 3 and 3 ', the valves open in accordance with the absolute value of the signal voltage, and a pilot pressure proportional to the signal voltage is generated downstream.
【００２４】前述のように、制御信号ＣＴの符号が反転
した時でも、符号に関わりなくその変化量に応じた遅れ
補正処理が施された補正信号ＭＤが生成され、符号が反
転した制御信号ＣＴに速やかに追随する補正信号ＭＤに
より、それぞれ電磁式比例減圧弁３，３′から信号電圧
に比例したパイロット圧を有したパイロット油が流出し
て方向切替弁４１を円滑に切り替えるから、操作者の操
作感覚とアクチュエーターの動きとのずれやアクチュエ
ーターの暴走あるいはショックの発生を防止できる。As described above, even when the sign of the control signal CT is inverted, the correction signal MD that has been subjected to the delay correction processing in accordance with the amount of change is generated regardless of the sign, and the control signal CT with the inverted sign is generated. The pilot signal having a pilot pressure proportional to the signal voltage flows out of each of the electromagnetic proportional pressure reducing valves 3 and 3 'by the correction signal MD which quickly follows the direction, and smoothly switches the direction switching valve 41. It is possible to prevent deviation between the operation feeling and the movement of the actuator, runaway of the actuator or occurrence of a shock.
【００２５】図７は図４に示した実施の形態を具体化し
た実施例に係る方向切替弁制御回路図である。同図にお
いて、１５，１５′は操作レバー７の順方向および逆方
向の操作に応じてそれぞれ切り替えられるパイロット弁
である。操作レバー７が一方向に操作されると、操作さ
れた側のパイロット弁１５または１５′が切り替わり、
その下流側には操作レバー７の操作量に応じたパイロッ
ト圧が発生する。そのパイロット圧は圧力センサー８，
８′により検出され、コントローラー２に制御信号ＣＴ
として伝達される。以下の動作は前述の実施例のものと
同様である。FIG. 7 is a directional control valve control circuit diagram according to an embodiment that embodies the embodiment shown in FIG. In the figure, reference numerals 15 and 15 'denote pilot valves which can be switched in accordance with the operation of the operation lever 7 in the forward and reverse directions, respectively. When the operating lever 7 is operated in one direction, the operated pilot valve 15 or 15 'is switched,
On the downstream side, a pilot pressure corresponding to the operation amount of the operation lever 7 is generated. The pilot pressure is the pressure sensor 8,
8 ', and sends a control signal CT to the controller 2.
Conveyed as The following operation is similar to that of the above-described embodiment.
【００２６】[0026]
【発明の効果】以上説明したように請求項１記載の発明
によれば、操作レバーが一方向から逆方向に到るまで操
作された時には、操作レバーの操作量を検知した制御信
号を一方向から逆方向まで連続した信号として取り扱っ
た遅れ補正処理により補正信号を演算し、方向切替弁の
切替え動作を行わせる補正信号を方向切替弁のスプール
を中立位置とする値で切り替えて、方向切替弁のスプー
ルを反対方向に駆動するための補正信号としたので、急
操作時に発生する衝撃を緩和しながら、操作レバーが一
方向から他方向まで連続して切り替えられた時の運転者
の操作感覚とのずれやアクチュエーターの暴走による危
険を抑止できる。請求項２記載の発明によれば、電気レ
バーである操作レバーの操作量を検出した制御信号に遅
れ補正処理を施して補正信号を演算し、該補正信号によ
り方向切替弁を駆動するようにしたので、制御信号の検
出機構が簡単で、操作レバーの操作に対する制御信号の
遅れがなく、応答特性が優れたものとすることができ
る。請求項３記載の発明によれば、パイロット弁を切り
替える操作レバーとして油圧レバーから流出したパイロ
ット油の油圧を検出した油圧信号を制御信号としたの
で、既存の油圧レバーを操作レバーとして用いることが
できるから、既存の製造設備を活用することにより製造
単価を低減することができる。As described above, according to the first aspect of the present invention, when the operation lever is operated from one direction to the opposite direction, the control signal detecting the operation amount of the operation lever is transmitted in one direction. Handled as a continuous signal from to
Delayed correction processing by calculating the correction signal, by switching the correction signal for causing the switching operation of the direction switching valve in value to the neutral position the spool of the direction switching valve, drive the spool of the square direction switching valve in opposition direction since the correction signal for, by suddenly while mitigating the impact generated during operation, runaway shift and actuators with the driver's operation feeling when the operating lever is switched successively from one direction to another direction Danger can be suppressed. According to the second aspect of the present invention, the control signal that has detected the operation amount of the operation lever that is an electric lever is subjected to a delay correction process to calculate a correction signal, and the correction signal is calculated.
Ri since so as to drive the direction switching valve, the control signal of the detection mechanism is simple, there is no delay in the control signal for the operation of the operating lever, it is possible to improve the response characteristics. According to the third aspect of the present invention, since the hydraulic pressure signal that detects the hydraulic pressure of the pilot oil flowing out from the hydraulic lever is used as the control signal as the control lever for switching the pilot valve, the existing hydraulic lever can be used as the control lever. Therefore, the manufacturing cost can be reduced by utilizing the existing manufacturing equipment.
【００２７】請求項４記載の発明によれば、油圧式方向
切替弁の双方の制御室に流入するパイロット油の油路中
にそれぞれ減圧弁を設け、方向切替弁のスプールを中立
位置とする値で切り替えられた補正信号に基づいて減圧
弁を制御することにより、方向切替弁を切り替え制御す
るようにしたので、既存の油圧駆動される方向切替弁や
パイロット油圧回路をそのまま用いることができ、単に
制御手段の演算処理方法を変更するだけで良いから、既
存の製造ラインには何の変更を加える必要がなく、製造
費用の増加を最小限に抑えることができる。請求項５記
載の発明によれば、遅れ補正処理は一次遅れ要素を用い
た演算処理としたので、制御手段の演算処理を比較的容
易に実行することができる。請求項６記載の発明によれ
ば、操作レバーが一方向から逆方向に到るまで操作され
た時には、操作レバーの操作量を検知した制御信号を一
方向から逆方向まで連続した信号として取り扱った遅れ
補正処理により補正信号を演算し、方向切替弁の切替え
動作をその全区間に亘って連続的に行う弁駆動手段に補
正信号を出力して方向切替弁の切替え動作を連続的に行
わせるようにしたので、方向切替弁の切替え機構を簡便
にかつ切替え動作を円滑に行わせることができる。According to the fourth aspect of the present invention, only setting the respective pressure reducing valve to the oil passage in the pilot oil that flows into the control chamber of both the hydraulic directional control valve to the neutral position the spool of the direction switching valve by controlling the pressure reducing valve based on the correction signal is switched in value, since the <br/> so that controls switches the direction switching valve, the direction switching valve and a pilot hydraulic circuit is conventional hydraulic drive as Can be used simply
Since it is only necessary to change the arithmetic processing method of the control means , there is no need to make any changes to the existing production line, and an increase in the production cost can be minimized. According to the fifth aspect of the present invention, since the delay correction processing is an arithmetic processing using a first-order delay element, the arithmetic processing of the control means can be relatively easily executed. According to the invention described in claim 6, when the operation lever is operated from one direction to the opposite direction, the control signal detecting the operation amount of the operation lever is treated as a continuous signal from one direction to the opposite direction . the delay correction process calculates a correction signal, continuously line switching behavior of the direction switching valve outputs a correction signal to continuously perform the valve driving means over its entire section a switching operation of the direction switching valve <br As a result, the switching mechanism of the direction switching valve can be simply and smoothly switched.
【図１】本発明の実施の形態の一例を示す概念図FIG. 1 is a conceptual diagram showing an example of an embodiment of the present invention.
【図２】操作レバーを急な戻し操作した時の制御信号Ｃ
Ｔと補正信号ＭＤの波形図FIG. 2 is a control signal C when the operation lever is suddenly returned.
Waveform diagram of T and correction signal MD
【図３】操作レバーを緩い戻し操作した時の制御信号Ｃ
Ｔと補正信号ＭＤの波形図FIG. 3 is a control signal C when the operation lever is loosely returned.
Waveform diagram of T and correction signal MD
【図４】本発明の実施の形態の他の一例を示す概念図FIG. 4 is a conceptual diagram showing another example of the embodiment of the present invention.
【図５】本発明の実施の形態のさらに他の一例を示す概
念図FIG. 5 is a conceptual diagram showing still another example of the embodiment of the present invention.
【図６】図１に示した本発明の実施の形態を具体化した
実施例に係る方向切替弁制御回路図FIG. 6 is a directional control valve control circuit diagram according to an example that embodies the embodiment of the present invention shown in FIG. 1;
【図７】図４に示した本発明の実施の形態を具体化した
実施例に係る方向切替弁制御回路図FIG. 7 is a directional control valve control circuit diagram according to an example that embodies the embodiment of the present invention shown in FIG. 4;
【図８】従来例に係る油圧駆動方式の制御回路の概略を
示すブロック図FIG. 8 is a block diagram schematically showing a hydraulic drive control circuit according to a conventional example.
【図９】従来例に係る油圧駆動方式の操作レバーを急な
戻し操作した時の制御信号ＣＴと補正信号ＭＤ，ＭＤ′
の波形図FIG. 9 shows a control signal CT and correction signals MD and MD 'when a hydraulically operated operating lever according to a conventional example is suddenly returned.
Waveform diagram of
【図１０】従来例に係る油圧駆動方式の操作レバーを緩
い戻し操作した時の制御信号ＣＴと補正信号ＭＤ，Ｍ
Ｄ′の波形図FIG. 10 shows a control signal CT and correction signals MD, M when a hydraulically operated operation lever according to a conventional example is loosely returned.
Waveform diagram of D '
【図１１】従来例に係る油圧駆動方式の操作レバーを中
立位置を越えて反対方向に緩い戻し操作した時の制御信
号ＣＴと補正信号ＭＤ，ＭＤ′の波形図FIG. 11 is a waveform diagram of a control signal CT and correction signals MD and MD 'when a hydraulically operated control lever according to a conventional example is gently returned in the opposite direction beyond a neutral position.
１ 操作量検出装置 ２ コントローラー ３，３′ 電磁式比例減圧弁 ４ 油圧制御装置 ５ アクチュエーター ７ 操作レバー ８ 圧力センサー １０ パイロット油圧ポンプ １５，１５′ パイロット弁 ４１ 方向切替弁 ４２ 制御駆動部 ４３ 油圧制御部 REFERENCE SIGNS LIST 1 operation amount detection device 2 controller 3, 3 ′ electromagnetic proportional pressure reducing valve 4 hydraulic control device 5 actuator 7 operation lever 8 pressure sensor 10 pilot hydraulic pump 15, 15 ′ pilot valve 41 direction switching valve 42 control drive unit 43 hydraulic control unit
───────────────────────────────────────────────────── フロントページの続き (56)参考文献 特開 平７−54806（ＪＰ，Ａ) (58)調査した分野(Int.Cl.7，ＤＢ名) E02F 9/22 E02F 9/20 ────────────────────────────────────────────────── (5) References JP-A-7-54806 (JP, A) (58) Fields investigated (Int. Cl. 7 , DB name) E02F 9/22 E02F 9/20
Claims (6)
アクチュエーターに供給される圧油の方向と流量を切り
替え制御する方向切替弁の切替え動作が、前記操作レバ
ーの操作量を検知した制御信号に遅れ補正処理が施され
た補正信号に基づいて行われるようにした方向切替弁制
御装置において、前記操作レバーが一方向に操作された
後、逆方向に到るまで操作された時には、前記制御信号
を前記操作レバーの中立位置で分離することなく、一方
向から逆方向まで連続した制御信号として取り扱った遅
れ補正処理により前記補正信号を演算し、前記補正信号
を前記方向切替弁のスプールを中立位置とする値で切り
替えて、前記方向切替弁のスプールを反対方向に駆動す
るための補正信号とする制御手段を具えたことを特徴と
する方向切替弁制御装置。1. A switching operation of a direction switching valve for switching and controlling a direction and a flow rate of pressure oil supplied to an actuator that is driven and controlled by operation of an operation lever is delayed from a control signal that detects an operation amount of the operation lever. In the direction switching valve control device configured to be performed based on the correction signal subjected to the correction processing, after the operation lever is operated in one direction, when the operation lever is operated until reaching the reverse direction, the control signal is Without separating at the neutral position of the operation lever, the correction signal is calculated by a delay correction process treated as a continuous control signal from one direction to the opposite direction , and the correction signal is output from the direction switching valve. switch in value to the neutral position the spool, before SL direction switching valve, characterized in that it comprises a control means for a correction signal for driving the spool of the direction switching valve in opposition direction Control device.
号は前記電気レバーから出力される前記操作レバーの操
作量を検出した信号であることを特徴とする請求項１記
載の方向切替弁制御装置。Wherein the operating lever is an electrical lever, the control signal according to claim 1 direction switching valve control, wherein the Ru signal der detecting the operation amount of the operation lever outputted from the electric lever apparatus.
油圧レバーであり、制御信号は前記油圧レバーから流出
したパイロット油の油圧を検出した油圧信号であること
を特徴とする請求項１記載の方向切替弁制御装置。Wherein the operating lever is a hydraulic lever for switching the pilot valve, the control signal is a direction switch of claim 1, wherein the Ru hydraulic signal der detecting the hydraulic pressure of the pilot oil that flows out from the hydraulic lever Valve control device.
イロット油の油路中にそれぞれ減圧弁が設けられ、前記
方向切替弁はパイロット油により切り替え制御される油
圧式切替弁であり、制御手段は前記減圧弁の開口量を制
御することにより、前記方向切替弁を切り替え制御する
ようにしたことを特徴とする請求項２または３記載の方
向切替弁制御装置。4. A path which flows into both control chambers of the directional control valve.
A pressure reducing valve is provided in each of the oil passages of the ilot oil, and the direction switching valve is an oil that is controlled to be switched by pilot oil.
A control valve for controlling the opening amount of the pressure reducing valve.
By control, controls switching the direction switching valve
Direction switching valve control device according to claim 2 or 3, wherein it has so.
算処理であることを特徴とする請求項１記載の方向切替
弁制御装置。5. The directional control valve control device according to claim 1, wherein the delay correction processing is an arithmetic processing using a first-order delay element.
アクチュエーターに供給される圧油の方向と流量を切り
替え制御する方向切替弁の切替え動作が、前記操作レバ
ーの操作量を検知した制御信号に遅れ補正処理が施され
た補正信号に基づいて行われるようにした方向切替弁制
御装置において、前記方向切替弁の切替え動作をその全
区間に亘って連続的に行う弁駆動手段と、前記操作レバ
ーが一方向に操作された後、逆方向に到るまで操作され
た時には、前記制御信号を前記操作レバーの中立位置で
分離することなく、一方向から逆方向まで連続した制御
信号として取り扱った遅れ補正処理により前記補正信号
を演算し、該補正信号を前記弁駆動手段に出力して前記
方向切替弁の切替え動作を連続的に行わせる制御手段と
を具えたことを特徴とする方向切替弁制御装置。6. A switching operation of a direction switching valve that switches and controls a direction and a flow rate of pressure oil supplied to an actuator that is driven and controlled by an operation of an operation lever is delayed from a control signal that detects an operation amount of the operation lever. In a directional control valve control device configured to be performed based on a correction signal that has been subjected to a correction process, the directional control valve switching operation is entirely performed.
Valve driving means for continuously operating over a section, and when the operation lever is operated in one direction and then operated in the opposite direction, the control signal is separated at a neutral position of the operation lever. Instead, the correction signal is calculated by a delay correction process treated as a continuous control signal from one direction to the reverse direction , and the correction signal is output to the valve driving means to perform the switching operation of the direction switching valve. Control means for continuous operation
A directional control valve control device , comprising:
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP03381396A JP3193616B2 (en) | 1996-02-21 | 1996-02-21 | Direction switching valve controller |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP03381396A JP3193616B2 (en) | 1996-02-21 | 1996-02-21 | Direction switching valve controller |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPH09228424A JPH09228424A (en) | 1997-09-02 |
| JP3193616B2 true JP3193616B2 (en) | 2001-07-30 |
Family
ID=12396927
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP03381396A Expired - Fee Related JP3193616B2 (en) | 1996-02-21 | 1996-02-21 | Direction switching valve controller |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JP3193616B2 (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US6599856B1 (en) | 1999-10-21 | 2003-07-29 | Tennex Corporation | Formed activated carbon and process for producing the same |
Families Citing this family (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP5966654B2 (en) * | 2012-06-21 | 2016-08-10 | コベルコ建機株式会社 | Swivel work machine |
-
1996
- 1996-02-21 JP JP03381396A patent/JP3193616B2/en not_active Expired - Fee Related
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US6599856B1 (en) | 1999-10-21 | 2003-07-29 | Tennex Corporation | Formed activated carbon and process for producing the same |
Also Published As
| Publication number | Publication date |
|---|---|
| JPH09228424A (en) | 1997-09-02 |
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