JPH0443157B2 - - Google Patents
Info
- Publication number
- JPH0443157B2 JPH0443157B2 JP17238684A JP17238684A JPH0443157B2 JP H0443157 B2 JPH0443157 B2 JP H0443157B2 JP 17238684 A JP17238684 A JP 17238684A JP 17238684 A JP17238684 A JP 17238684A JP H0443157 B2 JPH0443157 B2 JP H0443157B2
- Authority
- JP
- Japan
- Prior art keywords
- thrust cylinder
- hydraulic pump
- pressure
- variable displacement
- comparator
- 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
Links
- 238000006073 displacement reaction Methods 0.000 claims description 122
- 238000009412 basement excavation Methods 0.000 claims description 40
- 230000008602 contraction Effects 0.000 claims description 20
- 238000000034 method Methods 0.000 claims description 12
- 238000013459 approach Methods 0.000 claims description 8
- 230000000630 rising effect Effects 0.000 claims description 7
- 230000005284 excitation Effects 0.000 description 32
- 239000003921 oil Substances 0.000 description 26
- 238000010586 diagram Methods 0.000 description 13
- 230000007423 decrease Effects 0.000 description 9
- 238000001514 detection method Methods 0.000 description 8
- 239000002689 soil Substances 0.000 description 5
- 230000000694 effects Effects 0.000 description 4
- 239000004576 sand Substances 0.000 description 3
- 238000006243 chemical reaction Methods 0.000 description 2
- 230000003247 decreasing effect Effects 0.000 description 2
- 238000005516 engineering process Methods 0.000 description 2
- 230000007935 neutral effect Effects 0.000 description 2
- 238000007796 conventional method Methods 0.000 description 1
- 238000005553 drilling Methods 0.000 description 1
- 239000010720 hydraulic oil Substances 0.000 description 1
- 230000002093 peripheral effect Effects 0.000 description 1
- 230000010349 pulsation Effects 0.000 description 1
Landscapes
- Earth Drilling (AREA)
Description
【発明の詳細な説明】
〔産業上の利用分野〕
本発明は、アースドリルにおいて、回転バケツ
トが回転バケツト駆動系の油圧回路の最高効率付
近で掘削運転できるようにし、スラストシリンダ
の作動を制御する掘削作動制御方法に関するもの
である。[Detailed Description of the Invention] [Industrial Application Field] The present invention, in an earth drill, enables the rotary bucket to perform drilling operation near the maximum efficiency of the hydraulic circuit of the rotary bucket drive system, and controls the operation of the thrust cylinder. The present invention relates to an excavation operation control method.
アースドリルは、一般に、第１乃至第３図に示
すように、走行体１ａと、走行体１ａに対し旋回
自在な旋回体１ｂとからなるクレーン本体１に、
ジブ２の基端をピンにより俯抑可能に支持すると
共に、ジブ２の下部にフロントフレーム６の基端
をピンにより起伏可能に装着し、そのフロントフ
レーム６の先端にケリードライブ装置５をスラス
トシリンダ１０を介して取付けている。このケリ
ードライブ装置５は、ケーシング５ａに油圧モー
タ７を搭載し、その油圧モータ７の回転軸にピニ
オン７ａを取付け、前記ケーシング５ａにシヤフ
ト９を回転自在に軸承し、そのシヤフト９の外周
側面に噛合歯９ａを形成し、その噛合歯９ａと前
記ピニオン７ａとを噛合させ、前記シヤフト９に
四角形の長孔９ｂをシヤフト９の中心軸方向に設
けたものである。
Generally, as shown in FIGS. 1 to 3, an earth drill has a crane main body 1 consisting of a traveling body 1a and a revolving body 1b that can freely rotate relative to the traveling body 1a.
The base end of the jib 2 is supported by a pin so that it can be pushed down, and the base end of a front frame 6 is attached to the lower part of the jib 2 so that it can be raised and lowered, and the Kelly drive device 5 is attached to the tip of the front frame 6 as a thrust cylinder. It is attached via 10. This Kelly drive device 5 has a hydraulic motor 7 mounted on a casing 5a, a pinion 7a attached to the rotating shaft of the hydraulic motor 7, a shaft 9 rotatably supported on the casing 5a, and a shaft 9 mounted on the outer peripheral side of the shaft 9. A meshing tooth 9a is formed, the meshing tooth 9a meshes with the pinion 7a, and a rectangular long hole 9b is provided in the shaft 9 in the direction of the central axis of the shaft 9.
かかるケリードライブ装置５と前記スラストシ
リンダ１０とによりスラスターを構成する。 The Kelly drive device 5 and the thrust cylinder 10 constitute a thruster.
前記ジブ２の先端から巻上ロープ８により吊下
げた断面四角形のケリーバ３を前記シヤフト９の
長孔９ｂに挿通し、ケリードライブ装置５にケリ
ーバ３を回転可能にかつ巻上ロープ８の巻取り・
巻戻しにより昇降可能に取付け、そのケリーバ３
の下端に回転バケツト４を取付ける。前記油圧モ
ータ７に前記回転バケツト４にかかる負荷の程度
によつて自動的に吐出流量を制御する可変容量型
油圧ポンプ（第１図ないし第３図では図示してい
ないが本発明の一実施例を示した第４図中符号１
１にて示すものと同一のもので、以下油圧ポンプ
１１という。）を接続し、前記スラストシリンダ
１０を別の油圧ポンプで作動させるように構成し
ている。 The Kelly bar 3, which has a square cross section and is suspended from the tip of the jib 2 by a hoisting rope 8, is inserted into the elongated hole 9b of the shaft 9, and the Kelly bar 3 is rotatably attached to the Kelly drive device 5, and the hoisting rope 8 is wound up.・
It is installed so that it can be raised and lowered by unwinding, and its Kerryba 3
Attach the rotating bucket 4 to the lower end of the. A variable displacement hydraulic pump (not shown in FIGS. 1 to 3, but one embodiment of the present invention) automatically controls the discharge flow rate depending on the degree of load applied to the rotary bucket 4 by the hydraulic motor 7. Symbol 1 in Figure 4 shows
This pump is the same as that shown at 1, and is hereinafter referred to as a hydraulic pump 11. ), and the thrust cylinder 10 is operated by a separate hydraulic pump.
次に、その操作について説明すると、可変容量
型油圧ポンプ１１を作動させて油圧モータ７、ピ
ニオン７ａ、噛合歯９ａ、シヤフト９を介しケリ
ーバ３、回転バケツト４を正回転させる。このと
き、シヤフト９の四角形の長孔９ｂの４つの壁面
は、シヤフト９の回転トルクにより断面四角形の
ケリーバ３の角部に圧接係合し、その係合摩擦力
によりケリードライブ装置５とケリーバ３とがケ
リーバ３の軸方向（上下方向）に一体となる。次
に、スラストシリンダ用油圧ポンプを作動させて
スラストシリンダ１０をのばし、スラスト力（押
下げ力）を与えながらスラストシリンダ１０に取
付けられたケリードライブ装置５を介しケリーバ
３、回転バケツト４を押下げ、その回転バケツト
４により地盤を掘削し、その掘削した土砂を回転
バケツト４中に取り込む。前記スラストシリンダ
１０のピストンロツドが伸び側のストロークエン
ドまで伸長し、スラスターが下限位置に達したと
ころでケリーバ３、回転バケツト４の正回転を止
め、該ケリーバ３を一旦逆転（約0.5回転）させ
てケリーバ３とケリードライブ装置５のシヤフト
９との係合状態を解除し、それから、前記スラス
トシリンダ１０のピストンロツドを縮み側のスト
ロークエンドまで縮め、スラスターを上限位置ま
で持ち上げて復帰させる。そして、再びケリーバ
３、回転バケツト４を正回転させながら押下げて
地盤を掘削する。 Next, the operation will be described. The variable displacement hydraulic pump 11 is operated to rotate the Kelly lever 3 and the rotary bucket 4 in the forward direction via the hydraulic motor 7, pinion 7a, meshing teeth 9a, and shaft 9. At this time, the four walls of the rectangular elongated hole 9b of the shaft 9 are pressed into engagement with the corners of the Kelly bar 3 having a square cross section due to the rotational torque of the shaft 9, and the engagement friction force causes the Kelly drive device 5 and the Kelly bar 3 to are integrated in the axial direction (vertical direction) of the Kerry bar 3. Next, the hydraulic pump for the thrust cylinder is operated to extend the thrust cylinder 10, and while applying thrust force (pushing down force), the Kelly bar 3 and the rotary bucket 4 are pushed down via the Kelly drive device 5 attached to the thrust cylinder 10. , the ground is excavated by the rotating bucket cart 4, and the excavated earth and sand is taken into the rotating bucket cart 4. When the piston rod of the thrust cylinder 10 extends to the extension stroke end and the thruster reaches the lower limit position, the forward rotation of the Kelly bar 3 and the rotary bucket belt 4 is stopped, and the Kelly bar 3 is once reversed (approximately 0.5 rotation) to close the Kelly bar. 3 is disengaged from the shaft 9 of the Kelly drive device 5, then the piston rod of the thrust cylinder 10 is retracted to the stroke end on the contraction side, and the thruster is lifted to the upper limit position and returned. Then, the Kerry bar 3 and the rotary bucket 4 are pushed down again while rotating in the forward direction to excavate the ground.
以下、上述の操作、すなわちスラスターを押下
げ、下限位置に達したところで再び上限位置に復
帰させる操作を数回（土質の硬・軟や回転バケツ
ト４の深さによつて異なが約２〜４回）繰返し、
回転バケツト４内が掘削した土砂で満杯となつた
ところで、ケリーバ３および回転バケツト４を掘
削孔から巻上げ、それをダンプカー等の位置まで
旋回体１ｂを旋回させてそのダンプカー上に停止
させ、回転バケツト４を開口して掘削した土砂を
排出する。再び旋回体１ｂを掘削孔位置まで旋回
させ、ケリーバ３および回転バケツト４を掘削孔
に巻下げる。上述の掘削、巻上、排土、巻下の各
工程を繰返して堅孔を掘削する。 Next, repeat the above operation several times (approximately 2 to 4 times depending on the hardness or softness of the soil and the depth of the rotating bucket 4), i.e., pushing the thruster down and returning it to the upper limit position when it reaches the lower limit position. times) repeat,
When the inside of the rotary bucket 4 is filled with excavated earth and sand, the Kelly bar 3 and the rotary bucket 4 are hoisted up from the excavation hole, the revolving body 1b is rotated to the position of a dump truck, etc., and the rotary bucket 4 is stopped on top of the dump truck. 4 and discharge the excavated earth and sand. The rotating body 1b is rotated again to the position of the excavation hole, and the Kerry bar 3 and the rotary bucket cart 4 are lowered into the excavation hole. A hard hole is excavated by repeating the above-mentioned excavation, hoisting, earth removal, and hoisting steps.
かかるアースドリルにおいて、回転バケツト４
をその駆動系の油圧回路の最高効率点付近で掘削
運転するように操作することが重要である。回転
バケツト４を油圧回路最高効率点付近で掘削運転
させるには、可変容量型油圧ポンプ１１の吐出圧
力がその油圧回路最高効率点付近を維持するよう
にスラストシリンダ１０を伸縮操作する。すなわ
ち、スラストシリンダ１０を伸縮操作することに
より、回転バケツト４にかかる負荷を調節し、回
転バケツト４の負荷調節を介して可変容量型油圧
ポンプ１１の吐出圧力を回路最高効率点付近に維
持するように調節すれば、回転バケツト４を油圧
回路最高効率点付近で掘削運転させることができ
る。
In such an earth drill, the rotary bucket 4
It is important to operate the excavator so that the excavation operation is performed near the highest efficiency point of the hydraulic circuit of the drive system. In order to operate the rotary bucket 4 for excavation near the highest efficiency point of the hydraulic circuit, the thrust cylinder 10 is expanded or retracted so that the discharge pressure of the variable displacement hydraulic pump 11 is maintained near the highest efficiency point of the hydraulic circuit. That is, by expanding and contracting the thrust cylinder 10, the load applied to the rotary bucket belt 4 is adjusted, and the discharge pressure of the variable displacement hydraulic pump 11 is maintained near the highest efficiency point of the circuit through the load adjustment of the rotary bucket belt 4. By adjusting this, the rotary bucket cart 4 can be operated for excavation near the highest efficiency point of the hydraulic circuit.
ところが、従来、回転バケツト４を掘削運転さ
せるためのスラストシリンダ１０の伸縮操作は、
主として操作者の勘に頼つて行なわれている。こ
のため、回転バケツト４を常時油圧回路最高効率
点付近で掘削運転させることは非常に困難であ
り、掘削効率が操作者の熟練度により著しく差が
出るという問題がある。また、操作者の勘により
スラストシリンダ１０の伸縮操作を行なうため、
スラスト力をかけ過ぎて油圧回路がリリーフし、
バケツトが回転せずに掘削不能になつたり、フロ
ントフレーム６が持ち上がつたり、ジブ２が後方
にあおられる危険性もあり、逆にスラスト力が不
足すると回転バケツト４に負荷がかからず掘削効
率が悪くなるなどの問題がある。さらに、スラス
トシリンダ１０の作動開始、停止の操作を短時間
の内に繰り返すと、そのスラストシリンダ１０の
反力がフロントフレーム６およびジブ２に対する
加振力となつて振動を起すことがある。 However, conventionally, the operation of expanding and contracting the thrust cylinder 10 for operating the rotary bucket 4 in excavation operation is as follows.
This is done mainly by relying on the intuition of the operator. For this reason, it is very difficult to constantly operate the rotary bucket cart 4 in excavation operation near the highest efficiency point of the hydraulic circuit, and there is a problem in that the excavation efficiency varies significantly depending on the skill level of the operator. In addition, since the thrust cylinder 10 is expanded and contracted according to the operator's intuition,
If too much thrust force is applied, the hydraulic circuit will be relieved.
There is a risk that the bucket will not rotate and excavation will become impossible, the front frame 6 will be lifted, and the jib 2 will be thrown backwards. Conversely, if the thrust force is insufficient, no load will be applied to the rotating bucket 4. There are problems such as poor excavation efficiency. Furthermore, if the operation of starting and stopping the operation of the thrust cylinder 10 is repeated within a short period of time, the reaction force of the thrust cylinder 10 may become an excitation force on the front frame 6 and the jib 2, causing vibration.
なお、スラストシリンダ１０を自動制御する従
来技術として、本発明者の発明にかゝる特開昭58
−94591号公報がある。しかし、この公知技術は、
地盤が硬・軟いずれの状態にあつても回転バケツ
トにかゝる掘削負荷を一定に制御しようとするも
のであつて、回転バケツトをその駆動系の油圧回
路の最高効率点付近で掘削運転することについて
は考慮されていない。 In addition, as a conventional technique for automatically controlling the thrust cylinder 10, Japanese Patent Laid-Open No. 58-1991, which is based on an invention by the present inventor,
-There is a publication No. 94591. However, this known technology
The purpose is to control the excavation load on the rotary bucket to a constant level regardless of whether the ground is hard or soft, and the rotary bucket is operated near the highest efficiency point of the hydraulic circuit of its drive system. This has not been taken into consideration.
本発明は、前記の如き従来技術の問題点を改善
し、回転バケツト駆動回路の最高効率点付近で掘
削運転することができるアースドリルにおける掘
削作動制御方法を提供せんとするものである。 The present invention aims to improve the problems of the prior art as described above, and to provide a method for controlling the excavation operation in an earth drill, which enables excavation operation near the maximum efficiency point of the rotary bucket drive circuit.
本発明は、前記の如き目的を達成するため、回
転バケツトと、その回転バケツトの駆動用油圧モ
ータと、その油圧モータの駆動回路に圧油を供給
する可変容量型油圧ポンプと、前記回転バケツト
にスラスト力を与えるスラストシリンダと、その
スラストシリンダ作動用の油圧ポンプとを備えた
アースドリルにおいて、前記回転バケツト駆動回
路の油圧を検出し、その検出圧と比較器に設定し
た回転バケツト駆動回路の最高効率点における油
圧に相当する設定値とを比較し、検出圧が比較器
に設定した設定値より低いときはスラストシリン
ダを伸長させ、検出圧が比較器に設定した設定値
より高いときはスラストシリンダを縮小させるこ
とを特徴とする。
In order to achieve the above objects, the present invention provides a rotating bucket cart, a hydraulic motor for driving the rotating bucket cart, a variable displacement hydraulic pump for supplying pressure oil to a drive circuit of the hydraulic motor, and a hydraulic pump for supplying pressure oil to a drive circuit of the hydraulic motor. In an earth drill equipped with a thrust cylinder that provides thrust force and a hydraulic pump for operating the thrust cylinder, the hydraulic pressure of the rotary bucket drive circuit is detected, and the detected pressure and the maximum of the rotary bucket drive circuit are set in a comparator. The pressure is compared with the set value corresponding to the oil pressure at the efficiency point, and when the detected pressure is lower than the set value set on the comparator, the thrust cylinder is extended, and when the detected pressure is higher than the set value set on the comparator, the thrust cylinder is extended. It is characterized by reducing.
本発明は、前記の如く、回転バケツト駆動回路
の油圧を検出し、その検出圧と比較器に設定した
回転バケツト駆動回路の最高効率点における油圧
に相当する設定値とを比較し、検出値が設定値よ
り低いときはスラストシリンダを伸長方向に駆動
し、検出圧が設定値より高いときはスラストシリ
ンダを縮小方向に駆動するので、回転バケツトを
自動的にその駆動回路の最高効率点付近で掘削運
転させることができる。
As described above, the present invention detects the oil pressure of the rotary bucket drive circuit, compares the detected pressure with a set value corresponding to the oil pressure at the highest efficiency point of the rotary bucket drive circuit set in the comparator, and determines the detected value. When the detected pressure is lower than the set value, the thrust cylinder is driven in the extension direction, and when the detected pressure is higher than the set value, the thrust cylinder is driven in the contraction direction, so the rotating bucket is automatically excavated near the highest efficiency point of its drive circuit. can be driven.
以下、本発明のアースドリルにおける掘削作動
制御方向の実施例を第４図乃至第９図を参照して
説明する。
Hereinafter, embodiments of the excavation operation control direction in the earth drill of the present invention will be described with reference to FIGS. 4 to 9.
第４図乃至第６図は本発明のアースドリルにお
ける掘削作動制御方法の第１の実施例を示し、第
４図は油圧電気回路図、第５図は回転バケツト駆
動系の可変容量型油圧ポンプの吐出圧力、吐出流
量および油圧回路効率図、第６図は可変容量型油
圧ポンプの吐出圧力と両傾転式可変容量型油圧ポ
ンプの傾転量との関係図である。 4 to 6 show a first embodiment of the excavation operation control method for an earth drill according to the present invention, FIG. 4 is a hydraulic electric circuit diagram, and FIG. 5 is a variable displacement hydraulic pump with a rotary bucket drive system. FIG. 6 is a diagram showing the relationship between the discharge pressure of the variable displacement hydraulic pump and the tilting amount of the double tilting variable displacement hydraulic pump.
本発明を適用すべきアースドリルは、ケリード
ライブ装置の油圧モータ７に、回転バケツト４に
かかる負荷の程度に応じて自動的に吐出流量を制
御する可変容量型油圧ポンプ１１を切換弁１３を
介して接続し、一方、スラストシリンダ１０に
は、所謂両傾転式可変容量型油圧ポンプ１２を接
続する。すなわち、この両傾転式可変容量型油圧
ポンプ１２は、第１吸込吐出口Ｂと第２吸込吐出
口Ｒとを有し、その吸込側、吐出側を変換でき、
かつ吐出流量を調整することができるもので、そ
の第１吸込吐出口Ｂと第２吸込吐出口Ｒとを前記
スラストシリンダ１０のボトム室１０ａ側とロツ
ド室１０ｂ側とにそれぞれ接続する。また、スラ
ストシリンダ１０のボトム室１０ａと両傾転式可
変容量型油圧ポンプ１２の第１吸込吐出口Ｂ間の
油圧流路と、スラストシリンダ１０のロツド室１
０ｂと両傾転式可変容量型油圧ポンプ１２の第２
吸込吐出口Ｒ間の油圧流路との間に常閉切換弁１
４を接続する。この切換弁１４はスラストシリン
ダ１０のロツド側の圧力が高くなると、その圧力
をパイロツト圧として常閉位置からT3ポートに
切換わり、スラストシリンダ１０のボトム側の油
をタンクに逃すものである。 In the earth drill to which the present invention is applied, a variable displacement hydraulic pump 11 is connected to the hydraulic motor 7 of the Kelly drive device via a switching valve 13, and the discharge flow rate is automatically controlled according to the degree of load applied to the rotary bucket 4. On the other hand, a so-called double tilt variable displacement hydraulic pump 12 is connected to the thrust cylinder 10 . That is, this double tilting variable displacement hydraulic pump 12 has a first suction/discharge port B and a second suction/discharge port R, and the suction side and discharge side thereof can be converted.
The first suction/discharge port B and the second suction/discharge port R are connected to the bottom chamber 10a side and the rod chamber 10b side of the thrust cylinder 10, respectively. Further, a hydraulic flow path between the bottom chamber 10a of the thrust cylinder 10 and the first suction/discharge port B of the double tilting variable displacement hydraulic pump 12, and the rod chamber 1 of the thrust cylinder 10 are also provided.
0b and the second of the double tilting variable displacement hydraulic pump 12
A normally closed switching valve 1 is installed between the hydraulic flow path between the suction and discharge ports R.
Connect 4. When the pressure on the rod side of the thrust cylinder 10 becomes high, this switching valve 14 uses that pressure as pilot pressure and switches from the normally closed position to the T3 port, thereby releasing the oil on the bottom side of the thrust cylinder 10 to the tank.
また、前記可変容量型油圧ポンプ１１の吸込口
および前記両傾転式可変容量型油圧ポンプ１２の
第１吸込吐出口Ｂと第２吸込吐出口Ｒとにチヤー
ジ用の油圧ポンプ２３をチエツク弁を介して接続
する。 Also, check valves are installed at the suction port of the variable displacement hydraulic pump 11 and at the first suction and discharge ports B and the second suction and discharge port R of the double tilting variable displacement hydraulic pump 12. Connect via
また、両傾転式可変容量型油圧ポンプ１２に、
該油圧ポンプ１２の傾転量すなわち吐出流量と吸
込側、吐出側を変換する可変手段を連係する。こ
の可変手段は、伸長すると前記両傾転式可変容量
型油圧ポンプ１２の第１吸込吐出口Ｂを吐出側と
しかつその傾転量を増加せしめる単動式バネ付の
第１シリンダ２２ａと、同じく伸長すると前記両
傾転式可変容量型油圧ポンプ１２の第２吸込吐出
口Ｒを吐出側としかつその傾転量を増加せしめる
単動式バネ付の第２シリンダ２２ｂと、その第１
シリンダ２２ａおよび第２シリンダ２２ｂに圧油
を供給して傾転量を調整する傾転量調整用油圧ポ
ンプ２８と、その傾転量調整用油圧ポンプ２８と
第１シリンダ２２ａとの間に介装した常閉第１電
磁切換弁２４と、その第１シリンダ２２ａとタン
クとの間に介装した常閉第２電磁切換弁２５と、
前記傾転量調整用油圧ポンプ２８と第２シリンダ
２２ｂとの間に介装した常閉第３電磁切換弁２６
と、第２シリンダ２２ｂとタンクとの間に介装し
た常閉第４電磁切換弁２７とからなる。 In addition, the double tilting variable displacement hydraulic pump 12 includes
A variable means for converting the amount of tilting of the hydraulic pump 12, that is, the discharge flow rate, between the suction side and the discharge side is linked. This variable means is the same as the first cylinder 22a with a single-acting spring that, when extended, makes the first suction and discharge port B of the double tilting variable displacement hydraulic pump 12 the discharge side and increases the amount of tilting thereof. a single-acting spring-equipped second cylinder 22b which, when extended, makes the second suction and discharge port R of the double tilting variable displacement hydraulic pump 12 the discharge side and increases its tilting amount;
A hydraulic pump 28 for adjusting the tilting amount that supplies pressure oil to the cylinder 22a and the second cylinder 22b to adjust the amount of tilting is installed between the hydraulic pump 28 for adjusting the tilting amount and the first cylinder 22a. a normally closed first electromagnetic switching valve 24, a normally closed second electromagnetic switching valve 25 interposed between the first cylinder 22a and the tank,
a normally closed third electromagnetic switching valve 26 interposed between the tilting amount adjusting hydraulic pump 28 and the second cylinder 22b;
and a normally closed fourth electromagnetic switching valve 27 interposed between the second cylinder 22b and the tank.
前記第１電磁切換弁２４、第２電磁切換弁２５
および第３電磁切換弁２６、第４電磁切換弁２７
のソレノイドが、後述する第１継電器１８ａまた
は第２継電器１８ｂにより励磁されると、第１電
磁切換弁２４は常閉位置からP1ポートに切換わ
り、第２電磁切換弁２５は常閉位置からT1ポー
トに切換わり、第３電磁切換弁２６は常閉位置か
らP2ポートに切換わり、第４電磁切換弁２７は
常閉位置からT2ポートに切換わる。そして、消
磁されると、第１電磁切換弁２４はP1ポートか
ら常閉位置に自動復帰し、第２電磁切換弁２５は
T1ポートから常位置に自動復帰し、第３電磁切
換弁２６はP2ポートから常閉位置に自動復帰し、
第４電磁切換弁２７はT2ポートから常閉位置に
自動復帰する。このように、すべての電磁切換弁
が常閉位置にあるときは、シリンダー２２ａ，２
２ｂとも油圧的にロツクされ、両傾転式可変容量
型油圧ポンプ１２の傾転量は保持される。 The first electromagnetic switching valve 24 and the second electromagnetic switching valve 25
and a third electromagnetic switching valve 26 and a fourth electromagnetic switching valve 27
When the solenoid is excited by the first relay 18a or the second relay 18b, which will be described later, the first solenoid switching valve 24 switches from the normally closed position to the P1 port, and the second solenoid switching valve 25 switches from the normally closed position to the P1 port. The third solenoid switching valve 26 is switched from the normally closed position to the P2 port, and the fourth electromagnetic switching valve 27 is switched from the normally closed position to the T2 port. When demagnetized, the first solenoid switching valve 24 automatically returns to the normally closed position from the P1 port, and the second solenoid switching valve 25 automatically returns to the normally closed position from the P1 port.
It automatically returns to the normal position from the T1 port, and the third solenoid switching valve 26 automatically returns to the normally closed position from the P2 port.
The fourth electromagnetic switching valve 27 automatically returns to the normally closed position from the T2 port. In this way, when all the solenoid switching valves are in the normally closed position, the cylinders 22a, 2
2b are hydraulically locked, and the amount of tilting of the double tilting variable displacement hydraulic pump 12 is maintained.
前記油圧モータ７、切換弁１３間の油圧流路
（すなわち、回転バケツト４が正転しているとき
の油圧モータ７の入口と可変容量型油圧ポンプ１
１の吐出口との間の油圧流路。）中と、前記第１
電磁切換弁２４、第２電磁切換弁２５、第３電磁
切換弁２６および第４電磁切換弁２７との間に、
圧力検出器１５、フイルタ１６、比較器１７、第
１継電器１８ａおよび第２継電器１８ｂを設ける
と共に、前記比較器１７にスラスターレバー１９
用のポテンシヨメータ２０および両傾転式可変容
量型油圧ポンプ１２の傾転量用ポテンシヨメータ
２１を接続する。前記圧力検出器１５は油圧モー
タ７の正転入口側の圧力、すなわち可変容量型油
圧ポンプ１１の吐出圧力を電気信号に変化してフ
イルタ１６に送る。前記フイルタ１６は圧力検出
回路１５からの電圧信号の高周波成分（約10Hz以
上の圧力脈動）をカツトして比較器１７に送る。
前記スラスターレバー１９用のポテンシヨンメー
タ２０は、マニアル操作用のスラスターレバー１
９を操作すると、その抵抗値が変化し、それを比
較器１７に出力する。前記傾転量ポテンシヨンメ
ータ２１は前記両傾転式可変容量型油圧ポンプ１
２の傾転量に応じてその抵抗値が変化し、それを
比較器１７に出力する。前記比較器１７は、オー
ト操作においては、前記フイルタ１６からの高周
波成分をカツトされた電圧信号（検出電圧Exと
する。）と、前記傾転量用ポテンシヨメータ２１
からフイードバツクされた両傾転式可変容量型油
圧ポンプ１２の傾転量の情報信号と、予め設定さ
れた第１設定電圧Ed、第２設定電圧Eb、第３設
定電圧Ea、第４設定電圧Ecとを比較し、予め設
定された条件下で判断して第１継電器１８ａまた
は第２継電器１８ｂに通電する。また、マニアル
操作の場合は、ポテンシヨメータ２０からの信号
により、傾転量用ポテンシヨメータ２１の抵抗値
がポテンシヨメータ２０の抵抗値と同じになるよ
うに、第１継電器１８ａまたは第２継電器１８ｂ
に通電信号を出力する。前記第１継電器１８ａお
よび第２継電器１８ｂは、比較器１７から通電信
号を受けると、第１電磁切換弁２４、第４電磁切
換弁２７のソレノイドまたは第２電磁切換弁２
５、第３電磁切換弁２６のソレノイドを励磁す
る。 The hydraulic flow path between the hydraulic motor 7 and the switching valve 13 (i.e., the inlet of the hydraulic motor 7 and the variable displacement hydraulic pump 1 when the rotary bucket 4 is rotating normally)
Hydraulic flow path between the discharge port 1 and the discharge port 1. ) middle and said first
Between the electromagnetic switching valve 24, the second electromagnetic switching valve 25, the third electromagnetic switching valve 26, and the fourth electromagnetic switching valve 27,
A pressure detector 15, a filter 16, a comparator 17, a first relay 18a and a second relay 18b are provided, and the comparator 17 is provided with a thruster lever 19.
and the tilting amount potentiometer 21 of the double tilting variable displacement hydraulic pump 12 are connected. The pressure detector 15 converts the pressure on the forward rotation inlet side of the hydraulic motor 7 , that is, the discharge pressure of the variable displacement hydraulic pump 11 , into an electrical signal and sends it to the filter 16 . The filter 16 cuts off high frequency components (pressure pulsations of about 10 Hz or more) of the voltage signal from the pressure detection circuit 15 and sends it to the comparator 17.
The potentiometer 20 for the thruster lever 19 is the thruster lever 1 for manual operation.
9 changes its resistance value and outputs it to the comparator 17. The tilting amount potentiometer 21 is connected to the double tilting variable displacement hydraulic pump 1.
The resistance value changes according to the amount of tilting of the switch 2, and outputs it to the comparator 17. In automatic operation, the comparator 17 receives a voltage signal from the filter 16 with high frequency components removed (referred to as a detection voltage Ex) and the tilt amount potentiometer 21.
The information signal of the amount of tilting of the double tilting variable displacement hydraulic pump 12 fed back from , and energizes the first relay 18a or the second relay 18b based on a judgment made under preset conditions. In the case of manual operation, the signal from the potentiometer 20 is used to control the first relay 18a or the second Relay 18b
Outputs an energization signal to. When the first relay 18a and the second relay 18b receive the energization signal from the comparator 17, they activate the solenoid of the first electromagnetic switching valve 24, the fourth electromagnetic switching valve 27, or the second electromagnetic switching valve 2.
5. Energize the solenoid of the third electromagnetic switching valve 26.
前記比較器１７に予め設定された第１設定電圧
Edは、回転バケツト４が正転無負荷時における
可変容量油圧ポンプ１１の吐出圧力Pdである。
この第１設定電圧Edは、回転バケツト４が掘削
状態にあるか、またはそれ以外の状態（無負荷時
の正転、逆転および停止）にあるかを判断するも
のであつて、さらにこの第１設定電圧Edに相当
する吐出圧力Pdは、作動油温変化による粘度の
変化を考慮し、通常作業温度付近での圧力損失に
対して決定される。第２設定電圧Edは、正転掘
削時の回転バケツト４を駆動させる回転バケツト
駆動系の油圧回路（以下、単に油圧回路と称す。）
の最高効率点における可変容量型油圧ポンプ１１
の吐出圧力Pbに相当する。第３設定電圧Eaは、
前記第２設定電圧Ebに相当する吐出圧力Pbより
若干低い可変容量型油圧ポンプ１１の吐出圧力
Paに相当する。第４設定電圧Ecは、前記第２設
定電圧Ebに相当する吐出圧力Pbより若干高い可
変容量型油圧ポンプ１１の吐出圧力Pcに相当す
る。 a first set voltage preset in the comparator 17;
Ed is the discharge pressure Pd of the variable displacement hydraulic pump 11 when the rotary bucket 4 is rotating normally and under no load.
This first set voltage Ed determines whether the rotating bucket 4 is in the excavation state or in any other state (forward rotation, reverse rotation, and stop when no load is applied). The discharge pressure Pd, which corresponds to the set voltage Ed, is determined with respect to pressure loss near the normal working temperature, taking into account changes in viscosity due to changes in hydraulic oil temperature. The second set voltage Ed is a hydraulic circuit (hereinafter simply referred to as a hydraulic circuit) of a rotary bucket drive system that drives the rotary bucket 4 during normal excavation.
Variable displacement hydraulic pump 11 at the highest efficiency point of
This corresponds to the discharge pressure Pb. The third set voltage Ea is
The discharge pressure of the variable displacement hydraulic pump 11 is slightly lower than the discharge pressure Pb corresponding to the second set voltage Eb.
Corresponds to Pa. The fourth set voltage Ec corresponds to a discharge pressure Pc of the variable displacement hydraulic pump 11 that is slightly higher than the discharge pressure Pb corresponding to the second set voltage Eb.
前記比較器１７は、検出電圧Exが第１設定電
圧Ed以下にあるときには、オート操作は作動し
ないから、マニアル操作により傾転量用ポテンシ
ヨンメータ２１の抵抗値がポテンシヨンメータ２
０の抵抗値と同じになるように第１継電器１８ａ
または第２継電器１８ｂに励磁信号を出力する。 Since the comparator 17 does not operate automatically when the detected voltage Ex is below the first set voltage Ed, the resistance value of the tilting amount potentiometer 21 is changed to the value of the potentiometer 2 by manual operation.
the first relay 18a so that the resistance value is the same as that of 0.
Alternatively, an excitation signal is output to the second relay 18b.
検出電圧Exが第１設定電圧Edから第３設定電
圧Eaの範囲内にあるときは、第１継電器１８ａ
に両傾転式可変容量型油圧ポンプ１２の第１吸込
吐出口Ｂ側における傾転量が最大になるまで励磁
信号を出力する。 When the detected voltage Ex is within the range from the first set voltage Ed to the third set voltage Ea, the first relay 18a
An excitation signal is output until the amount of tilting on the first suction/discharge port B side of the double tilting variable displacement hydraulic pump 12 reaches a maximum.
検出電圧Exが第３設定電圧Eaから第２設定電
圧Ebの範囲内にあつて、かつ検出電圧Exが可変
容量型油圧ポンプ１１の吐出圧力の上昇に伴つて
第３設定電圧Eaから第２設定電圧Ebへと上昇中
にあるときには、第２継電器１８ｂに励磁信号を
出力し、他方、検出電圧Exが吐出圧力の下降に
伴つて第２設定電圧Ebから第３設定電圧Eaへと
下降中にあるときには、第１継電器１８ａに励磁
信号を出力し、第１吸込吐出口Ｂ側における傾転
量を調整する。 When the detected voltage Ex is within the range from the third set voltage Ea to the second set voltage Eb, and the detected voltage Ex changes from the third set voltage Ea to the second set voltage as the discharge pressure of the variable displacement hydraulic pump 11 increases. When the voltage is increasing to Eb, an excitation signal is output to the second relay 18b, and on the other hand, while the detected voltage Ex is decreasing from the second set voltage Eb to the third set voltage Ea as the discharge pressure decreases. At certain times, an excitation signal is output to the first relay 18a to adjust the amount of tilting on the first suction/discharge port B side.
検出電圧Exが第４設定電圧Ec以上にあるとき
には、第２継電器１８ｂに両傾転式可変容量型油
圧ポンプ１２の第２吸込吐出口Ｒ側における傾転
量が最大になるまで励磁信号を出力する。 When the detected voltage Ex is equal to or higher than the fourth set voltage Ec, an excitation signal is output to the second relay 18b until the amount of tilting on the second suction/discharge port R side of the double tilting variable displacement hydraulic pump 12 reaches a maximum. do.
検出電圧Exが第２設定電圧Ebから第４設定電
圧Ecの範囲内にあつて、かつ検出電圧Exが可変
容量型油圧ポンプ１１と吐出圧力の上昇に伴つて
第２設定電圧Ebから第４設定電圧Ecへと上昇中
にあるときには、第２継電器１８ｂに励磁信号を
出力し、他方、検出電圧Exが吐出圧力の下降に
伴つて第４設定電圧Ecから第２設定電圧Ebへと
下降中にあるときには、第１継電器１８ａに励磁
信号を出力し、第２吸込吐出口Ｒ側における傾転
量を調整する。 When the detected voltage Ex is within the range from the second set voltage Eb to the fourth set voltage Ec, and the detected voltage Ex changes from the second set voltage Eb to the fourth set voltage as the discharge pressure of the variable displacement hydraulic pump 11 increases. When the voltage is increasing to Ec, an excitation signal is output to the second relay 18b, and on the other hand, while the detected voltage Ex is decreasing from the fourth set voltage Ec to the second set voltage Eb as the discharge pressure decreases. At certain times, an excitation signal is output to the first relay 18a to adjust the amount of tilting on the second suction/discharge port R side.
検出電圧Exが第２設定電圧Ebにあるときに
は、第１継電器１８ａおよび第２継電器１８ｂへ
の励磁信号を断ち、両傾転式可変容量型油圧ポン
プ１２の傾転量を０にする。 When the detected voltage Ex is at the second set voltage Eb, the excitation signal to the first relay 18a and the second relay 18b is cut off, and the amount of tilting of the double tilting variable displacement hydraulic pump 12 is made zero.
本発明のアースドリルにおける掘削作動制御方
法は、以上の如き構成の装置を使用し、以下述べ
るようにして制御する。 The excavation operation control method for an earth drill according to the present invention uses the apparatus configured as described above and is controlled as described below.
まず、切換弁１３を中立位置からＰポートに切
換える。すると、可変容量型油圧ポンプ１１から
の圧油は、実線矢印に示すように流れ、油圧モー
タ７が正転し、この油圧モータ７、ピニオン７
ａ、シヤフト９、ケリーバ３を介して回転バケツ
ト４が正転して地盤を掘削する。このとき、可変
容量型油圧ポンプ１１の吐出圧力は、回転バケツ
ト４が掘削を開始するまで無負荷時の圧力Pd以
下であり、掘削を開始したところで圧力が上昇し
Pd以上となる。このPd以上の可変容量型油圧ポ
ンプ１１の吐出圧力は、圧力検出器１５により検
出電圧Exに変換される。この検出電圧Exはフイ
ルター１６を経て比較器１７へと送られ、比較器
１７において、上述の検出電圧Exと、傾転量用
ポテンシヨメータ２１からの傾転量と、比較器１
７の設定された第１設定電圧Ed、第２設定電圧
Eb、第３設定電圧Ea、第４設定電圧Ecとが比較
される。 First, the switching valve 13 is switched from the neutral position to the P port. Then, the pressure oil from the variable displacement hydraulic pump 11 flows as shown by the solid line arrow, the hydraulic motor 7 rotates normally, and the hydraulic motor 7 and pinion 7
a. The rotary bucket 4 rotates normally via the shaft 9 and the Kelly bar 3 to excavate the ground. At this time, the discharge pressure of the variable displacement hydraulic pump 11 is below the pressure Pd when there is no load until the rotary bucket 4 starts digging, and the pressure increases when the rotating bucket 4 starts digging.
It becomes Pd or more. The discharge pressure of the variable displacement hydraulic pump 11 that is greater than or equal to Pd is converted into a detected voltage Ex by the pressure detector 15. This detection voltage Ex is sent to the comparator 17 via the filter 16, and in the comparator 17, the above-mentioned detection voltage Ex, the tilting amount from the tilting amount potentiometer 21, and the comparator 1
7 set first setting voltage Ed, second setting voltage
Eb, third set voltage Ea, and fourth set voltage Ec are compared.
いま、回転バケツト４は正転掘削を開始したと
ころであり、可変容量型油圧ポンプ１１の吐出圧
力はPd以上となるので、検出電圧と設定電圧と
の関係はEx≧Edとな、比較器１７は回転バケツ
ト４が掘削を開始した状態にあると判断し、第１
継電器１８ａに両傾転式可変容量型油圧ポンプ１
２の第１吸込吐出口Ｂ側における傾転量が最大
（すなわち、スラストシリンダ１０の伸長速度が
最大。）となるまで励磁信号を出力する。すると、
第１電磁切換弁２４が常閉位置からP1ポートに
切換わり、かつ第４電磁切換弁２７が常閉位置か
らT2ポートに切換わり、それに伴つて傾転量調
整用油圧ポンプ２８からの圧油が第１電磁切換弁
２４を経て第１シリンダ２２ａに供給され、その
第１シリンダ２２ａが伸長する。その結果、両傾
転式可変容量型油圧ポンプ１２は第１吸込吐出口
Ｂを吐出側とし、かつその傾転量を最大となす。
その結果両傾転式可変容量型油圧ポンプ１２の第
１吸込吐出口Ｂから吐出された圧油は実線矢印方
向に流れてスラストシリンダ１０のボトム室１０
ａに供給され、スラストシリンダ１０は最高速度
で伸長する。 Now, the rotary bucket 4 has just started normal rotation excavation, and the discharge pressure of the variable displacement hydraulic pump 11 is greater than Pd, so the relationship between the detected voltage and the set voltage is Ex≧Ed, and the comparator 17 is It is determined that the rotary bucket 4 has started excavation, and the first
A double tilting variable displacement hydraulic pump 1 is installed in the relay 18a.
The excitation signal is output until the amount of tilting on the first suction/discharge port B side of No. 2 reaches the maximum (that is, the extension speed of the thrust cylinder 10 reaches the maximum). Then,
The first electromagnetic switching valve 24 switches from the normally closed position to the P 1 port, and the fourth electromagnetic switching valve 27 switches from the normally closed position to the T 2 port, and accordingly, the rotation amount adjustment hydraulic pump 28 Pressure oil is supplied to the first cylinder 22a via the first electromagnetic switching valve 24, and the first cylinder 22a is extended. As a result, the double tilting variable displacement hydraulic pump 12 has the first suction/discharge port B on the discharge side, and its tilting amount is maximized.
As a result, the pressure oil discharged from the first suction and discharge port B of the double tilting variable displacement hydraulic pump 12 flows in the direction of the solid line arrow, and flows into the bottom chamber 10 of the thrust cylinder 10.
a, and the thrust cylinder 10 extends at maximum speed.
なお、前述のスラストシリンダ１０の伸長に伴
つて、両傾転式可変容量型油圧ポンプ１２の吸込
側、すなわち第２吸込吐出口Ｒの油が不足する
が、その分チヤージ用油圧ポンプ２３によつて供
給される。 Note that as the thrust cylinder 10 expands, the oil on the suction side of the double tilting variable displacement hydraulic pump 12, that is, the second suction and discharge port R, becomes insufficient. supplied.
また、スラストシリンダ１０のロツド室１０ａ
側の油は実線矢印に示すように両傾転式可変容量
型油圧ポンプ１２の第２吸込吐出口Ｒ側に流れ
る。 In addition, the rod chamber 10a of the thrust cylinder 10
The oil on the side flows to the second suction/discharge port R side of the double tilting variable displacement hydraulic pump 12 as shown by the solid line arrow.
さらに、上述の第１シリンダ２２ａが伸長する
と、第２シリンダ２２ｂが縮み、その第２シリン
ダ２２ｂ中の油は第４電磁切換弁２７のT2ポー
トを経てタンクに戻る。 Further, when the first cylinder 22a described above expands, the second cylinder 22b contracts, and the oil in the second cylinder 22b returns to the tank via the T2 port of the fourth electromagnetic switching valve 27.
また、両傾転式可変容量型油圧ポンプ１２の傾
転量が最大となると、ポテンシヨメータ２１の信
号により比較器１７が判断して、第１継電器１８
ａへの励磁信号の出力を断つ。従つて、第１電磁
切換弁２４はP1ポートから常閉位置に、また第
４電磁切換弁２７はT2ポートから常閉位置にそ
れぞれ自動復帰し、第１シリンダ２２ａ内の油が
油圧的にロツクされ両傾転式可変容量型油圧ポン
プ１２の傾転量は保持される。 Further, when the tilting amount of the double tilting variable displacement hydraulic pump 12 reaches the maximum, the comparator 17 determines based on the signal from the potentiometer 21, and the first relay 18
Cut off the output of the excitation signal to a. Therefore, the first electromagnetic switching valve 24 automatically returns to the normally closed position from the P1 port, and the fourth electromagnetic switching valve 27 automatically returns to the normally closed position from the T2 port, so that the oil in the first cylinder 22a is hydraulically restored. The amount of tilting of the double tilting variable displacement hydraulic pump 12 is maintained.
このように、スラストシリンダ１０が最大速度
で伸長すると、回転バケツト４が地盤に食い込
み、掘削負荷が増加する。従つて、可変容量型油
圧ポンプ１１の吐出圧力が上昇してPa以上とな
る。 In this way, when the thrust cylinder 10 extends at the maximum speed, the rotating bucket belt 4 digs into the ground, increasing the excavation load. Therefore, the discharge pressure of the variable displacement hydraulic pump 11 increases and becomes equal to or higher than Pa.
この吐出圧力がPa乃至Pcの範囲内にある場合
は、第６図に例示の如く吐出圧力がPbになるよ
うに、すなわち回路効率が最高となるように、ス
ラストシリンダ１０を伸縮作動させる。 When this discharge pressure is within the range of Pa to Pc, the thrust cylinder 10 is operated to expand and contract so that the discharge pressure becomes Pb, that is, the circuit efficiency is maximized, as illustrated in FIG.
以下、上述の作動をさらに詳細に説明する。ま
ず、吐出圧力がPa乃至Pbの範囲内にあつて、か
つ上昇中の場合には、検出電圧と設定電圧との関
係がEa＜Ex＜Ebとなり、比較器１７は吐出圧力
がPbに近づいて来ている状態、すなわち油圧回
路が最高効率点に近づいて来ている状態と判断
し、第２継電器１８ｂに励磁信号を出力する。す
ると、第３電磁切換弁２６は常閉位置からP2ポ
ートに、また第２電磁切換弁２５は常閉位置から
T1ポートにそれぞれ切換わる。それに伴つて傾
転量調整用油圧ポンプ２８からの圧油が第３電磁
切換弁２６を経て第２シリンダ２２ｂに供給さ
れ、その第２シリンダ２２ｂが伸長する。その結
果、両傾転式可変容量型油圧ポンプ１２は第１吸
込吐出口Ｂが吐出側のまま、その傾転量が最大か
ら次第に減少し、かつ、そのときの傾転量の状態
はポテンシヨメータ２１によつて比較器１７に伝
えられる。従つて、両傾転式可変容量型油圧ポン
プ１２の第１吸込吐出口Ｂから吐出される圧油は
最大量から減少し、スラストシリンダ１０は最大
速度から減速されて伸長を続ける。このときの傾
転量はポテンシヨメータ２１により比較器１７に
フイードバツクされ、図６に示すように、圧力に
みあつた傾転量になつた時に継電器１８ｂへの出
力を停止する。なお、上述の第２シリンダ２２ｂ
が伸長すると、第１シリンダ２２ａが縮み、その
第１シリンダ２２ａの中の油は第２電磁切換弁２
５のT1のポートを経てタンクに戻る。 The above operation will be explained in more detail below. First, when the discharge pressure is within the range of Pa to Pb and is increasing, the relationship between the detected voltage and the set voltage becomes Ea<Ex<Eb, and the comparator 17 detects that the discharge pressure approaches Pb. It is determined that the hydraulic circuit is approaching the highest efficiency point, and outputs an excitation signal to the second relay 18b. Then, the third electromagnetic switching valve 26 changes from the normally closed position to the P2 port, and the second electromagnetic switching valve 25 changes from the normally closed position to the P2 port.
T Switches to 1 port respectively. Along with this, pressure oil from the tilting amount adjusting hydraulic pump 28 is supplied to the second cylinder 22b via the third electromagnetic switching valve 26, and the second cylinder 22b is extended. As a result, the tilting amount of the double tilting variable displacement hydraulic pump 12 gradually decreases from the maximum while the first suction and discharge port B remains on the discharge side. It is transmitted to the comparator 17 by the meter 21. Therefore, the amount of pressure oil discharged from the first suction and discharge port B of the double tilting variable displacement hydraulic pump 12 decreases from the maximum amount, and the thrust cylinder 10 continues to expand while being decelerated from its maximum speed. The amount of tilting at this time is fed back to the comparator 17 by the potentiometer 21, and as shown in FIG. 6, when the amount of tilting meets the pressure, the output to the relay 18b is stopped. Note that the above-mentioned second cylinder 22b
When the first cylinder 22a expands, the first cylinder 22a contracts, and the oil in the first cylinder 22a is transferred to the second electromagnetic switching valve 2.
Return to the tank via port 5 T 1 .
また、吐出圧力がPa乃至Pbの範囲内にあつて、
かつ下降中の場合には、比較器１７は吐出圧力が
Pbより離れて行く状態、すなわち油圧回路が最
高効率点より離れて行く状態にあると判断し、第
２継電器１８ｂへの励磁信号を断ち、第１継電器
１８ａに励磁信号を出力する。すると、第３電磁
切換弁２６はP2ポートから常閉位置に、また第
２電磁切換弁２５はT1ポートから常閉位置にそ
れぞれ自動復帰し、第１電磁切換弁２４はP1ポ
ートに、また第４電磁切換弁２７はT2ポートに
それぞれ切換わる。従つて、第１シリンダ２２ａ
が伸長し、第２シリンダ２２ｂが縮み、両傾転式
可変容量型油圧ポンプ１２の傾転量が増す。その
結果、両傾転式可変容量型油圧ポンプ１２からの
吐出流量が増し、スラストシリンダ１０の伸長速
度が加速される。このときの両傾転式可変容量型
油圧ポンプ１２の傾転量はポテンシヨメータ２１
によつて比較器１７にフイードバツクされ、図６
に示すように、油圧ポンプ１１の吐出圧力にみあ
つた傾転量になるまで継電器１８ａに励磁信号を
出力する。 In addition, when the discharge pressure is within the range of Pa to Pb,
And if it is descending, the comparator 17 indicates that the discharge pressure is
It is determined that the hydraulic circuit is moving away from Pb, that is, the hydraulic circuit is moving away from the highest efficiency point, and the excitation signal to the second relay 18b is cut off, and the excitation signal is output to the first relay 18a. Then, the third electromagnetic switching valve 26 automatically returns to the normally closed position from the P2 port, the second electromagnetic switching valve 25 automatically returns to the normally closed position from the T1 port, and the first electromagnetic switching valve 24 automatically returns to the normally closed position from the P1 port. , and the fourth electromagnetic switching valve 27 is switched to the T2 port. Therefore, the first cylinder 22a
expands, the second cylinder 22b contracts, and the amount of tilting of the double tilting variable displacement hydraulic pump 12 increases. As a result, the discharge flow rate from the double tilt variable displacement hydraulic pump 12 increases, and the extension speed of the thrust cylinder 10 is accelerated. At this time, the amount of tilting of the double tilting variable displacement hydraulic pump 12 is determined by the potentiometer 21.
is fed back to the comparator 17 by
As shown in FIG. 2, an excitation signal is output to the relay 18a until the amount of tilting matches the discharge pressure of the hydraulic pump 11.
次に、吐出圧力がPb乃至Pcの範囲内にあつて、
かつ上昇中の場合には、検出電圧と設定電圧との
関係がEb＜Ex＜Ecとなり、比較器１７は吐出圧
力がPbより離れて行く状態にあると判断し、第
２継電器１８ｂに励磁信号を出力する。なお、第
１継電器１８ａに励磁信号を出力中の場合は、第
１継電器１８ａへの励磁信号の出力を断つてか
ら、第２継電器１８ｂに励磁信号を出力する。そ
の結果、第３電磁切換弁２６がP2ポートに、第
２電磁切換弁２５がT1ポートにそれぞれ切換わ
り、（第１電磁切換弁２４は常閉位置に、第４電
磁切換弁２７も常閉位置に位置する。）第２シリ
ンダ２２ｂが伸長して第１シリンダ２２ａが縮
む。すると、両傾転式可変容量型油圧ポンプ１２
は第２吸込吐出口Ｒを吐出側とし、かつその傾転
量を最大へと近づくように変動する。従つて、両
傾転式可変容量型油圧ポンプ１２の第２吸込吐出
口Ｒから吐出された圧油は破線矢印方向に流れて
スラストシリダ１０のロツド室１０ｂに供給さ
れ、スラストシリンダ１０は加速して縮む。この
ときの両傾転式可変容量型油圧ポンプ１２の傾転
量は、ポテンシヨメータ２１によつて比較器１７
にフイードバツクされ、図６に示すように、可変
容量型油圧ポンプ１１の吐出圧力にみあつた傾転
になるまで比較器１７は継電器１８ｂに励磁信号
を出力する。 Next, when the discharge pressure is within the range of Pb to Pc,
If the voltage is rising, the relationship between the detected voltage and the set voltage becomes Eb<Ex<Ec, and the comparator 17 determines that the discharge pressure is moving away from Pb, and sends an excitation signal to the second relay 18b. Output. Note that when the excitation signal is being output to the first relay 18a, the excitation signal is output to the second relay 18b after cutting off the output of the excitation signal to the first relay 18a. As a result, the third electromagnetic switching valve 26 is switched to the P2 port, the second electromagnetic switching valve 25 is switched to the T1 port, (the first electromagnetic switching valve 24 is in the normally closed position, and the fourth electromagnetic switching valve 27 is also switched to the normally closed position). ) The second cylinder 22b extends and the first cylinder 22a contracts. Then, the double tilting variable displacement hydraulic pump 12
sets the second suction/discharge port R on the discharge side, and changes its tilt amount so as to approach the maximum. Therefore, the pressure oil discharged from the second suction and discharge port R of the double tilting variable displacement hydraulic pump 12 flows in the direction of the broken line arrow and is supplied to the rod chamber 10b of the thrust cylinder 10, and the thrust cylinder 10 is accelerated. Shrink. At this time, the amount of tilting of the double tilting variable displacement hydraulic pump 12 is determined by the comparator 17 by the potentiometer 21.
As shown in FIG. 6, the comparator 17 outputs an excitation signal to the relay 18b until the tilt rotation matches the discharge pressure of the variable displacement hydraulic pump 11.
なお、上述のスラストシリンダ１０の縮みに伴
つて、両傾転式可変容量型油圧ポンプ１２の吸込
側、すなわち第１吸込吐出口Ｂ側の油が過多にな
る。このときスラストシリンダ１０はケリードラ
イブ装置を持上げているので両傾転式可変容量型
油圧ポンプ１２のＲ側は高圧になり、切換弁１４
がT3ポートに切換わつて余つた油をタンクに戻
す。 In addition, as the thrust cylinder 10 described above contracts, the amount of oil on the suction side of the double tilting variable displacement hydraulic pump 12, that is, on the side of the first suction and discharge port B becomes excessive. At this time, the thrust cylinder 10 is lifting the Kelly drive device, so the R side of the double tilting variable displacement hydraulic pump 12 becomes high pressure, and the switching valve 14
is switched to T3 port and excess oil is returned to the tank.
また、吐出圧力がPb乃至Pcの範囲内にあつて、
かつ下降中の場合には、比較器１７は吐出圧力が
Pbに近づいて来ている状態、すなわち油圧回路
が最高効率点に近づいて来ている状態にあると判
断し、第２継電器１８ｂへの励磁信号を断ち、第
１継電器１８ａに励磁信号を出力する。すると、
第３電磁切換弁２６はPZポートから常閉位置に、
また第２電磁切換弁２５はT1ポートから常閉位
置にそれ自動復帰し、第１電磁切換弁２４はP1
ポートに、また第４電磁切換弁２７はT2ポート
にそれぞれ切換わる。従つて、第１シリンダ２２
ａが伸長し、第２シリンダ２２ｂが縮み、両傾転
式可変容量型油圧ポンプ１２は第２吸込吐出口Ｒ
を吐出側のまま、その傾転量が最大から減少す
る。従つて、両傾転式可変容量型油圧ポンプ１２
の第２吸込吐出口Ｒから吐出される圧油は最大量
から減少し、スラストシリンダ１０は最高速度か
ら減速されながら縮み続ける。 In addition, if the discharge pressure is within the range of Pb to Pc,
And if it is descending, the comparator 17 indicates that the discharge pressure is
It determines that the hydraulic circuit is approaching Pb, that is, the hydraulic circuit is approaching the highest efficiency point, cuts off the excitation signal to the second relay 18b, and outputs the excitation signal to the first relay 18a. . Then,
The third solenoid switching valve 26 is placed in the normally closed position from the P Z port.
Further, the second solenoid switching valve 25 automatically returns to the normally closed position from the T1 port, and the first solenoid switching valve 24 automatically returns to the normally closed position from the T1 port.
port, and the fourth electromagnetic switching valve 27 is switched to the T2 port. Therefore, the first cylinder 22
a expands, the second cylinder 22b contracts, and the double tilting variable displacement hydraulic pump 12 opens the second suction and discharge port R.
remains on the discharge side, and its tilt amount decreases from the maximum. Therefore, the double tilting variable displacement hydraulic pump 12
The pressure oil discharged from the second suction/discharge port R decreases from the maximum amount, and the thrust cylinder 10 continues to contract while being decelerated from its maximum speed.
このようにして、吐出圧力がPaまたはPcから
Pbに近づいてPbとなると、検出電圧と設定電圧
との関係がEx＝Ebとなり、比較器１７は油圧回
路が最高効率点にあると判断し、傾転量が０にな
るまで第１継電器１８ａまたは第２継電器１８ｂ
に通電し、傾転量が０に戻つた時第１継電器１８
ａまたは第２継電器１８ｂへの励磁信号の出力を
断つ。すると、第１電磁切換弁２４、第２電磁切
換弁２５、第３電磁切換弁２６、第４電磁切換弁
２７が常閉位置に復帰し、第１シリンダ２２ａお
よび第２シリンダ２２ｂの伸縮が停止し、油圧的
にこの状態がロツクされる。このため、両傾転式
可変容量型油圧ポンプ１２から圧油が吐出され
ず、従つてスラストシリンダ１０の伸縮が停止
し、回転バケツト４は油圧回路の最高効率点で地
盤を掘削する。 In this way, the discharge pressure changes from Pa or Pc to
When it approaches Pb and reaches Pb, the relationship between the detected voltage and the set voltage becomes Ex=Eb, and the comparator 17 determines that the hydraulic circuit is at the highest efficiency point, and the first relay 18a is switched on until the tilt amount becomes 0. or second relay 18b
is energized, and when the tilt amount returns to 0, the first relay 18
a or the output of the excitation signal to the second relay 18b is cut off. Then, the first electromagnetic switching valve 24, the second electromagnetic switching valve 25, the third electromagnetic switching valve 26, and the fourth electromagnetic switching valve 27 return to the normally closed position, and the expansion and contraction of the first cylinder 22a and the second cylinder 22b stop. However, this state is hydraulically locked. For this reason, pressure oil is not discharged from the double tilting variable displacement hydraulic pump 12, and therefore the thrust cylinder 10 stops expanding and contracting, and the rotary bucket 4 excavates the ground at the highest efficiency point of the hydraulic circuit.
このように、油圧回路の効率最高点に近づくに
従つてスラストシリンダ１０の伸縮速度が０に近
づくので、回転バケツト駆動回路の油圧を最高効
率点に調整して合せ易い効果がある。 In this manner, the expansion and contraction speed of the thrust cylinder 10 approaches 0 as the efficiency of the hydraulic circuit approaches its maximum point, which has the effect of making it easier to adjust the hydraulic pressure of the rotary bucket drive circuit to its maximum efficiency.
さらに、吐出圧力がPc以上になつた場合には、
検出電圧と設定電圧との関係がEx≧Ecとなり、
比較器１７は回路効率が低下し、またリリーフす
る虞れがある状態にあると判断し、第２継電器１
８ｂに、両傾転式可変容量型油圧ポンプ１２の第
２吸込吐出口Ｒ側における傾転量が最大となるま
で励磁信号を出力する。すると、第３電磁切換弁
２６がP2ポートに、第２電磁切換弁２５がT1ポ
ートにそれぞれ切換わり、第２シリンダ２２ｂが
伸長して第１シリンダ２２ａが縮み、両傾転式可
変容量型油圧ポンプ１２は第２吸込吐出口Ｒを吐
出側としてその傾転量を最大となす。その結果、
スラストシリンダ１０は最高速度で縮む。このと
きの両傾転式可変容量型油圧ポンプ１２の傾転量
は、ポテンシヨメータ２１によつて比較器１７に
フイードバツクされ、両傾転式可変容量型油圧ポ
ンプ１２のＲ側の吐出の最大傾転になつた時、比
較器１７は継電器１８ｂへの励磁信号を停止す
る。その結果、第２電磁切換弁２５がT1ポート
から常閉位置に切換わり、第３電磁切換弁２６が
P2ポートから常閉位置に切換わり、シリンダ２
２ａ，２２ｂは油圧的にロツクされ、両傾転式可
変容量型油圧ポンプ１２の傾転量は維持される。 Furthermore, if the discharge pressure exceeds Pc,
The relationship between the detection voltage and the set voltage is Ex≧Ec,
The comparator 17 determines that the circuit efficiency is reduced and there is a risk of relief, and the second relay 1
8b, an excitation signal is outputted until the amount of tilting on the second suction/discharge port R side of the double tilting variable displacement hydraulic pump 12 reaches a maximum. Then, the third electromagnetic switching valve 26 switches to the P2 port, the second electromagnetic switching valve 25 switches to the T1 port, the second cylinder 22b expands and the first cylinder 22a contracts, and the double tilting variable displacement The type hydraulic pump 12 maximizes its tilting amount with the second suction/discharge port R on the discharge side. the result,
Thrust cylinder 10 retracts at maximum speed. At this time, the amount of tilting of the double tilting variable displacement hydraulic pump 12 is fed back to the comparator 17 by the potentiometer 21, and the amount of tilting of the double tilting variable displacement hydraulic pump 12 is fed back to the comparator 17. When tilting occurs, the comparator 17 stops sending the excitation signal to the relay 18b. As a result, the second solenoid switching valve 25 switches from the T1 port to the normally closed position, and the third solenoid switching valve 26 switches to the normally closed position.
Switches from P 2 port to normally closed position, cylinder 2
2a and 22b are hydraulically locked, and the amount of tilting of the double tilting variable displacement hydraulic pump 12 is maintained.
以上のように、両傾転式可変容量型油圧ポンプ
１２の傾転量の大小は、継電器１８ａ，１８ｂに
励磁信号を出力する時間の長さで決まる。通電時
間が長ければ大きな傾転となる。通電を停止する
と、その傾転状態は油圧的にロツクされることに
より維持される。 As described above, the amount of tilting of the double tilting variable displacement hydraulic pump 12 is determined by the length of time for outputting the excitation signal to the relays 18a, 18b. If the energization time is long, the tilt will be large. When the power is turned off, the tilting state is maintained by being hydraulically locked.
以上のようにして、可変容量型油圧ポンプ１１
の吐出圧力はほぼPa乃至Pc間において維持され、
この吐出圧力Pa乃至Pcの間は、回転バケツト４
を回転させる油圧回路効率の最大となる吐出圧力
Pbを基準とした前後の狭い範囲であるので、回
転バケツト４は常に油圧回路最高効率点付近で掘
削運転を行なうことができる。また、回転バケツ
ト４にかけるスラスト力は、可変容量型油圧ポン
プ１１の吐出圧力がPa乃至Pcの間となるように
ほぼ一定に保持されるので、従来の操作者が勘に
よりスラストシリンダ１０の伸縮操作を行なつて
いたものと比べて回転バケツト４にスラスト力を
かけ過ぎたり、あるいはスラスト力が不足したり
するようなことはない。しかも、スラストシリン
ダ１０の作動開始、停止の操作を短時間の内に繰
り返してそのスラストシリンダ１０の反力が起振
力となつてフロントフレームやジブが振動すると
いうようなこともない。 As described above, the variable displacement hydraulic pump 11
The discharge pressure is maintained approximately between Pa and Pc,
Between this discharge pressure Pa and Pc, the rotating bucket 4
The discharge pressure that maximizes the efficiency of the hydraulic circuit that rotates the
Since the range is narrow in front and behind based on Pb, the rotary bucket 4 can always perform excavation operation near the highest efficiency point of the hydraulic circuit. Furthermore, since the thrust force applied to the rotary bucket 4 is kept almost constant so that the discharge pressure of the variable displacement hydraulic pump 11 is between Pa and Pc, conventional operators can expand and contract the thrust cylinder 10 by intuition. There is no possibility that too much thrust force is applied to the rotating bucket cart 4 or that the thrust force is insufficient compared to the one that was being operated. Furthermore, the front frame and the jib do not vibrate due to the reaction force of the thrust cylinder 10 becoming an excitation force due to repeated operations of starting and stopping the operation of the thrust cylinder 10 within a short period of time.
次に、切換弁１３を中立位置に切換えて回転バ
ケツト４を停止させているとき、また切換弁１３
をＮポートに切換えて回転バケツト４を逆転させ
ているとき、もしくは切換弁１３がＰポートに切
換わつていても回転バケツト４が正転無負荷のと
きは、回転バケツト４の掘削圧力は低く、可変容
量型油圧ポンプ１１の吐出圧力がPd以下となり、
検出電圧と設定電圧との関係がEx≦Edとなり、
比較器１７は回転バケツト４が停止、逆転、空転
の状態にあると判断し、第１継電器１８ａまたは
第２継電器１８ｂは通電されることはなく、従つ
てスラストシリンダ１０は作動しない。 Next, when the switching valve 13 is switched to the neutral position and the rotary bucket 4 is stopped, the switching valve 13
When the rotary bucket 4 is reversed by switching to the N port, or when the rotary bucket 4 is in normal rotation with no load even if the switching valve 13 is switched to the P port, the excavation pressure of the rotary bucket 4 is low. , the discharge pressure of the variable displacement hydraulic pump 11 becomes below Pd,
The relationship between the detection voltage and the set voltage is Ex≦Ed,
The comparator 17 determines that the rotary bucket 4 is in a stopped, reversed, or idling state, and the first relay 18a or the second relay 18b is not energized, so the thrust cylinder 10 does not operate.
第５図は可変容量型油圧ポンプ１１の吐出流量
と吐出圧力および油圧回路の効率図である。 FIG. 5 is a diagram showing the discharge flow rate and discharge pressure of the variable displacement hydraulic pump 11 and the efficiency of the hydraulic circuit.
横軸に吐出圧力を、縦軸に吐出流量および効率
を表わす。図中、〔Ｉ〕は馬力制御可能な吐出圧
力P0より大きい吐出圧力の馬力制御域、イは等
馬力曲線、ロは可変容量型油圧ポンプ１１の吐出
流量、、吐出圧力線、ハは油圧回路の効率曲線、
Pdは第１設定電圧Edにより設定された回転バケ
ツト４の正転無負荷空転時における吐出圧力、
Pbは第２設定電圧Ebにより設定された回転バケ
ツト４の掘削時の油圧回路最高効率点における吐
出圧力、Paは第３設定電圧Eaにより設定された
上述の吐出圧力Pbより若干低い吐出圧力、Pcは
第４設定電圧Ecにより設定された上述の吐出圧
力Pbより若干高い吐出圧力である。 The horizontal axis represents the discharge pressure, and the vertical axis represents the discharge flow rate and efficiency. In the figure, [I] is the horsepower control range of discharge pressure greater than P 0 where horsepower can be controlled, A is the equal horsepower curve, B is the discharge flow rate of the variable displacement hydraulic pump 11, , the discharge pressure line, and C is the oil pressure circuit efficiency curve,
Pd is the discharge pressure of the rotating bucket 4 set by the first set voltage Ed when the rotating bucket 4 is idling with no load;
Pb is the discharge pressure at the highest efficiency point of the hydraulic circuit of the rotary bucket 4 during excavation, set by the second set voltage Eb, Pa is the discharge pressure slightly lower than the above-mentioned discharge pressure Pb, set by the third set voltage Ea, Pc is a discharge pressure slightly higher than the above-mentioned discharge pressure Pb set by the fourth set voltage Ec.
この図からも明らかなように、本発明のアース
ドリルによる掘削作動制御方法は、油圧回路の効
率の最大となる吐出圧力Pbを基準とした若干低
い吐出圧力Pa乃至若干高い吐出圧力Pcの範囲、
すなわち油圧回路最高効率点付近で回転バケツト
４を掘削運転させることができる。 As is clear from this figure, the method for controlling the excavation operation using an earth drill according to the present invention is based on the discharge pressure Pb, which maximizes the efficiency of the hydraulic circuit, in the range of a slightly lower discharge pressure Pa to a slightly higher discharge pressure Pc,
In other words, the rotary bucket 4 can be operated for digging near the highest efficiency point of the hydraulic circuit.
第６図は、両傾転式可変容量型油圧ポンプ１２
の傾転量と可変容量型油圧ポンプ１１の吐出圧力
との関係図である。 Figure 6 shows a double tilting variable displacement hydraulic pump 12.
2 is a relationship diagram between the amount of tilting and the discharge pressure of the variable displacement hydraulic pump 11. FIG.
横軸に可変容量型油圧ポンプ１１の吐出圧力、
縦軸に両傾転式可変容量型油圧ポンプ１２の傾転
量を表わす。図中、Pd，Pa，Pb，Pcは前述した
ので、ここでは省略する。 The horizontal axis represents the discharge pressure of the variable displacement hydraulic pump 11,
The vertical axis represents the amount of tilting of the double tilting variable displacement hydraulic pump 12. In the figure, Pd, Pa, Pb, and Pc have been described above, so they are omitted here.
第７図は本発明のアースドリルによる掘削作動
制御方法の他の実施例を示した可変容量型油圧ポ
ンプ１１の吐出圧力と両傾転式可変容量型油圧ポ
ンプ１２の傾転量との関係図である。 FIG. 7 is a diagram showing the relationship between the discharge pressure of the variable displacement hydraulic pump 11 and the tilting amount of the double tilting variable displacement hydraulic pump 12, showing another embodiment of the method for controlling the excavation operation using an earth drill according to the present invention. It is.
この実施例は、両傾転式可変容量型油圧ポンプ
１２の傾転量の変化率、すなわちスラストシリン
ダ１０の伸縮速度の変化率を二段切換えとなし、
回路効率の最高点付近での圧力変動によるスラス
ターの急激な昇降を防ぐものである。すなわち、
可変容量型油圧ポンプ１１の吐出圧力PaとPbと
の間の吐出圧力Peに相当する第５設定電圧Eeと、
同じく吐出圧力PbとPcとの間の吐出圧力Pfに相
当する第６設定電圧Efとを比較器１７に設定す
る。このようにすれば、検出電圧Exが第３設定
電圧Ea（吐出圧力Paに相当する。）乃至第５設定
電圧Eeの範囲内、または第６設定電圧Ef乃至第
４設定電圧Ec（吐出圧力Pcに相当する。）の範囲
内にある場合と、検出電圧Exが第５設定電圧Ee
乃至第６設定電圧Efの範囲内にある場合とにお
ける両傾転式可変容量型油圧ポンプ１２の傾転量
の増減変動を二段に異ならしめて、スラストシリ
ンダ１０の伸縮速度の変化率を二段階に切換える
ことができる。この結果、目的とする回路効率最
高点に対応する吐出圧力Pb付近での両傾転式可
変容量型油圧ポンプ１２の傾転量の増減幅が小さ
くなり、従つて目標圧力Pb付近での圧力変動に
よる急激なスラスターの昇降を防ぎ、フロントフ
レーム６のあおりや異常振動を防止することがで
きる。 In this embodiment, the rate of change in the amount of tilting of the double tilting variable displacement hydraulic pump 12, that is, the rate of change in the expansion/contraction speed of the thrust cylinder 10, is switched in two stages.
This prevents the thruster from rising and falling rapidly due to pressure fluctuations near the highest point of circuit efficiency. That is,
a fifth set voltage Ee corresponding to the discharge pressure Pe between the discharge pressures Pa and Pb of the variable displacement hydraulic pump 11;
Similarly, a sixth set voltage Ef corresponding to the discharge pressure Pf between the discharge pressures Pb and Pc is set in the comparator 17. In this way, the detection voltage Ex is within the range of the third set voltage Ea (corresponding to the discharge pressure Pa) to the fifth set voltage Ee, or the sixth set voltage Ef to the fourth set voltage Ec (corresponding to the discharge pressure Pc). ) and the detection voltage Ex is within the range of the fifth set voltage Ee.
The rate of change in the expansion/contraction speed of the thrust cylinder 10 is set in two stages by varying the increase/decrease in the amount of tilting of the double tilting variable displacement hydraulic pump 12 between the range of the sixth set voltage Ef and the sixth set voltage Ef. can be switched to As a result, the range of increase/decrease in the amount of tilting of the double tilting variable displacement hydraulic pump 12 becomes small around the discharge pressure Pb corresponding to the target highest point of circuit efficiency, and therefore the pressure fluctuation around the target pressure Pb becomes smaller. It is possible to prevent the thruster from rising and falling rapidly due to this, and to prevent the front frame 6 from being tilted or abnormally vibrated.
第８図および第９図は本発明のアースドリルに
おける掘削作動制御方法の他の実施例を示し、第
８図は可変容量型油圧ポンプ１１の吐出圧力と両
傾転式可変容量型油圧ポンプ１２の傾転量との関
係図、第９図は可変容量型油圧ポンプ１１の吐出
圧力の圧力変化速度と両傾転式可変容量型油圧ポ
ンプ１２の傾転量との関係図である。 8 and 9 show other embodiments of the excavation operation control method in the earth drill of the present invention, and FIG. 8 shows the discharge pressure of the variable displacement hydraulic pump 11 and the double tilting variable displacement hydraulic pump 12. FIG. 9 is a diagram showing the relationship between the pressure change rate of the discharge pressure of the variable displacement hydraulic pump 11 and the tilting amount of the double tilting variable displacement hydraulic pump 12.
この実施例においては、可変容量型油圧ポンプ
１１の吐出圧力Pdに相当する第１設定電圧Edか
ら吐出圧力Paに相当する第３設定電圧Eaの範囲
内と、吐出圧力Pcに相当する第４設定電圧Ec以
上との制御を上述の実施例と同様に行い、第３設
定電圧Eaから第４設定電圧Ecの範囲内の制御を、
可変容量型油圧ポンプ１１の吐出圧力の上昇下降
変化速度に応じて両傾転式可変容量型油圧ポンプ
１２の傾転量を調整するものである。すなわち、
可変容量型油圧ポンプ１１の吐出圧力の上昇速
度、下降速度を演算する演算手段を比較器１７に
内蔵し、比較器１７は可変容量型油圧ポンプ１１
の吐出圧力が上昇中には第２継電器１８ｂに励磁
信号を出力し、下降中には第１継電器１８ａに励
磁信号を出力し、かつ上昇、下降の圧力変化速度
が大きい程両傾転式可変容量型油圧ポンプ１２の
傾転量を大きくするように第１継電器１８ａまた
は第２継電器１８ｂに励磁信号を出力するもので
ある。このときの両傾転式可変容量型油圧ポンプ
１２の傾転量はポテンシヨメータ２１により比較
器１７にフイードバツクされ、第９図に示す油圧
ポンプ１１の圧力変化速度に対する傾転量になる
ように比較器１７は継電器１８ａ，１８ｂに励磁
信号を出力する。 In this embodiment, the range is from the first set voltage Ed corresponding to the discharge pressure Pd of the variable displacement hydraulic pump 11 to the third set voltage Ea corresponding to the discharge pressure Pa, and the fourth set voltage corresponds to the discharge pressure Pc. The voltage Ec or higher is controlled in the same way as in the above embodiment, and the control is performed within the range from the third set voltage Ea to the fourth set voltage Ec.
The amount of tilting of the double tilting variable displacement hydraulic pump 12 is adjusted in accordance with the rate of change in the rise and fall of the discharge pressure of the variable displacement hydraulic pump 11. That is,
The comparator 17 has a built-in calculating means for calculating the rate of rise and fall of the discharge pressure of the variable displacement hydraulic pump 11.
When the discharge pressure is rising, an excitation signal is output to the second relay 18b, and when it is falling, an excitation signal is output to the first relay 18a. An excitation signal is output to the first relay 18a or the second relay 18b so as to increase the amount of tilting of the displacement hydraulic pump 12. At this time, the amount of tilting of the double tilting variable displacement hydraulic pump 12 is fed back to the comparator 17 by the potentiometer 21, and the amount of tilting is adjusted to be the amount of tilting relative to the pressure change rate of the hydraulic pump 11 shown in FIG. Comparator 17 outputs an excitation signal to relays 18a and 18b.
このようにすることにより、可変容量型油圧ポ
ンプ１１の吐出圧力が上昇中にはスラストシリン
ダ１０を縮め、逆に吐出圧力が下降中にスラスト
シリンダ１０を伸長せさ、かつ吐出圧力の上昇、
下降の変化速度に応じてスラストシリンダの伸縮
速度を調整することができる。この結果、可変容
量型油圧ポンプ１１の吐出圧力の変化を少なくな
るように、スラスターを昇降制御することがで
き、従つて可変容量型油圧ポンプ１１の吐出圧力
の急変にスラスターの昇降を追従する能力が向上
される。すなわち、地盤が軟土から硬土に、硬土
から軟土に変化したとき、回転バケツト４の掘削
負荷が変化し、可変容量型油圧ポンプ１１の吐出
圧力が変化させられるが、その変化に追従してス
ラスターの昇降制御能力が向上される。 By doing this, the thrust cylinder 10 is contracted while the discharge pressure of the variable displacement hydraulic pump 11 is rising, and conversely, the thrust cylinder 10 is expanded when the discharge pressure is falling, and the discharge pressure is increased.
The expansion and contraction speed of the thrust cylinder can be adjusted according to the rate of change in descent. As a result, it is possible to control the elevation of the thruster so as to reduce the change in the discharge pressure of the variable displacement hydraulic pump 11, and therefore the ability to follow the elevation and descent of the thruster to sudden changes in the discharge pressure of the variable displacement hydraulic pump 11. is improved. That is, when the ground changes from soft soil to hard soil or from hard soil to soft soil, the excavation load of the rotary bucket 4 changes, and the discharge pressure of the variable displacement hydraulic pump 11 changes, but it follows the change. This improves the ability to control the thruster's elevation.
最後にマニアル操作について説明する。スラス
ターをマニアル操作で昇降させる場合は、スラス
ターレバー１９を操作する。すると、スラスター
レバー用のポテンシヨメータ２０の抵抗値が変化
し、比較器１７はスラスターの昇降をマニアル操
作で行なうと判断し、傾転量用ポテンシヨメータ
２１の抵抗値が上述のスラスターレバー用ポテン
シヨメータ２０の抵抗値になるまで、第１継電器
１８ａまたは第２継電器１８ｂに励磁信号を出力
する。すなわち、スラスターレバ１９の操作量
（傾転量）に応じて両傾転式可変容量型油圧ポン
プ１２の傾転量を調整することができる。なお、
図中では、マニアル操作とオート操作を切換える
スイツチは省略した。 Finally, I will explain manual operation. When raising and lowering the thruster manually, operate the thruster lever 19. Then, the resistance value of the potentiometer 20 for the thruster lever changes, the comparator 17 determines that the thruster should be raised and lowered manually, and the resistance value of the potentiometer 21 for tilting amount changes to the above-mentioned value for the thruster lever. An excitation signal is output to the first relay 18a or the second relay 18b until the resistance value of the potentiometer 20 is reached. That is, the amount of tilting of the double tilting variable displacement hydraulic pump 12 can be adjusted according to the amount of operation (amount of tilting) of the thruster lever 19. In addition,
In the diagram, the switch for switching between manual operation and automatic operation is omitted.
なお、前記の実施例は、ポンプ制御方式により
スラストシリンダへの油の供給方向を切換えると
共にその供給油量を連続的に変化させるものにつ
いて説明したが、通常のポンプを使用し、比較制
御電磁切換弁方式により同様に制御することがで
きる。 In the above embodiment, the pump control method was used to switch the direction of oil supply to the thrust cylinder and to continuously change the amount of oil supplied. It can be similarly controlled by a valve system.
以上述べたように、本発明は、回転バケツト駆
動系の油圧回路圧力を検出し、その検出圧が油圧
回路最高効率点に対応する設定値より低いときは
スラストシリンダを伸長させ、検出圧が油圧回路
最高効率点に対応する設定値より高いときはスラ
ストシリンダを縮小させるので、回転バケツトを
自動的にその駆動系の油圧回路最高効率点付近に
おいて掘削運転することができ、これにより掘削
効率を向上させることができる。
As described above, the present invention detects the hydraulic circuit pressure of a rotary bucket drive system, and when the detected pressure is lower than a set value corresponding to the highest efficiency point of the hydraulic circuit, the thrust cylinder is extended, and the detected pressure Since the thrust cylinder is reduced when the value is higher than the set value corresponding to the circuit's highest efficiency point, the rotary bucket can automatically operate the rotary bucket near the highest efficiency point of the hydraulic circuit of its drive system, thereby improving excavation efficiency. can be done.
また、特許請求の範囲第２項および第３項の発
明は、前記の如くして自動的に回転バケツト駆動
系の油圧回路最高効率点付近において掘削運転を
行なうと共に、油圧回路の最高効率点付近では、
スラストシリンダの伸縮速度を減少させるので、
回転バケツト駆動回路の油圧を最高効率点に調整
して合わせ易い効果がある。 Further, the inventions of claims 2 and 3 automatically perform the excavation operation near the highest efficiency point of the hydraulic circuit of the rotary bucket drive system as described above, and also perform the excavation operation near the highest efficiency point of the hydraulic circuit. Well then,
Because it reduces the expansion and contraction speed of the thrust cylinder,
This has the effect of making it easier to adjust the oil pressure of the rotary bucket drive circuit to the highest efficiency point.
また、特許請求の範囲第４項の発明は、前記の
如くして自動的に回転バケツト駆動系の油圧回路
最高効率点付近において掘削運転を行なうと共
に、油圧回路の最高効率点付近では、圧力の変化
速度に応じて両傾転式可変容量型油圧ポンプの傾
転量を調整するので、掘削負荷の変化に追従して
回転バケツトを昇降制御することができる効果が
ある。 Further, the invention of claim 4 automatically performs the excavation operation near the highest efficiency point of the hydraulic circuit of the rotary bucket drive system as described above, and at the same time, the pressure decreases near the highest efficiency point of the hydraulic circuit. Since the amount of tilting of the double tilting variable displacement hydraulic pump is adjusted according to the rate of change, it is possible to control the elevation of the rotary bucket in accordance with changes in the excavation load.
第１図はアースドリルの全体構成を示す図、第
２図はケリードライブ装置の正面図、第３図は第
２図の−線断面図である。第４図乃至第６図
は本発明の一実施例を示し、第４図は油圧電気回
路図、第５図は回転バケツト駆動系の可変容量型
油圧ポンプの吐出圧力、吐出流量および油圧回路
効率図、第６図は可変容量型油圧ポンプの吐出圧
力と両傾転式可変容量型油圧ポンプの傾転量との
関係図である。第７図は第６図に示す実施例を変
化させた他の実施例を示す可変容量型油圧ポンプ
の吐出圧力と両傾転式可変容量型油圧ポンプの傾
転量との関係図である。第８図および第９図は本
発明の他の実施例を示し、第８図は可変容量型油
圧ポンプの吐出圧力と両傾転式可変容量型油圧ポ
ンプの傾転量との関係図、第９図は可変容量型油
圧ポンプの吐出圧力の圧力変化速度と両傾転式可
変容量型油圧ポンプの傾転量との関係図である。
１……クレーン本体、２……ジブ、３……ケリ
ーバ、４……回転バケツト、５……ケリードライ
ブ装置、６……フロントフレーム、７……油圧モ
ータ、１０……スラストシリンダ、１１……回転
バケツト駆動系の可変容量型油圧ポンプ、１２…
…両傾転式可変容量型油圧ポンプ、１３……切換
弁、１４……切換弁、１５……圧力検出器、１６
……フイルタ、１７……比較器、１８ａ……第１
継電器、１８ｂ……第２継電器、１９……スラス
ターレバー、２０……スラスターレバ用ポテンシ
ヨメータ、２１……傾転量用ポテンシヨメータ、
２２ａ……第１シリンダ、２２ｂ……第２シリン
ダ、２３……チヤージ用油圧ポンプ、２４……第
１電磁切換弁、２５……第２電磁切換弁、２６…
…第３電磁切換弁、２７……第４電磁切換弁、２
８……傾転用油圧ポンプ、Ed……第１設定電圧、
Eb……第２設定電圧、Ea……第３設定電圧、Ec
……第４設定電圧、Pd……第１設定電圧に相当
する吐出圧力、Pb……第２設定電圧に相当する
吐出圧力、Pa……第３設定電圧に相当する吐出
圧力、Pc……第４設定電圧に相当する吐出圧力。
FIG. 1 is a diagram showing the overall configuration of the earth drill, FIG. 2 is a front view of the Kelly drive device, and FIG. 3 is a sectional view taken along the line -- in FIG. 2. 4 to 6 show an embodiment of the present invention, FIG. 4 is a hydraulic electric circuit diagram, and FIG. 5 is a discharge pressure, discharge flow rate, and hydraulic circuit efficiency of a variable displacement hydraulic pump with a rotary bucket drive system. FIG. 6 is a diagram showing the relationship between the discharge pressure of the variable displacement hydraulic pump and the amount of tilting of the double tilting variable displacement hydraulic pump. FIG. 7 is a diagram showing the relationship between the discharge pressure of a variable displacement hydraulic pump and the tilting amount of a double tilting variable displacement hydraulic pump showing another embodiment that is a variation of the embodiment shown in FIG. 6. 8 and 9 show other embodiments of the present invention, and FIG. 8 is a diagram of the relationship between the discharge pressure of the variable displacement hydraulic pump and the tilting amount of the double tilting variable displacement hydraulic pump, and FIG. FIG. 9 is a relationship diagram between the pressure change rate of the discharge pressure of the variable displacement hydraulic pump and the amount of tilting of the double tilting variable displacement hydraulic pump. DESCRIPTION OF SYMBOLS 1... Crane body, 2... Jib, 3... Kelly bar, 4... Rotating bucket, 5... Kelly drive device, 6... Front frame, 7... Hydraulic motor, 10... Thrust cylinder, 11... Variable displacement hydraulic pump with rotary bucket drive system, 12...
...Double tilting variable displacement hydraulic pump, 13...Switching valve, 14...Switching valve, 15...Pressure detector, 16
...Filter, 17...Comparator, 18a...1st
Relay, 18b...second relay, 19...thruster lever, 20...potentiometer for thruster lever, 21...potentiometer for tilting amount,
22a...first cylinder, 22b...second cylinder, 23...charging hydraulic pump, 24...first electromagnetic switching valve, 25...second electromagnetic switching valve, 26...
...Third electromagnetic switching valve, 27...Fourth electromagnetic switching valve, 2
8... Hydraulic pump for tilting, Ed... First set voltage,
Eb...Second set voltage, Ea...Third set voltage, Ec
...Fourth setting voltage, Pd...Discharge pressure corresponding to the first setting voltage, Pb...Discharge pressure corresponding to the second setting voltage, Pa...Discharge pressure corresponding to the third setting voltage, Pc...Discharge pressure corresponding to the second setting voltage, Pc...Discharge pressure corresponding to the second setting voltage, 4Discharge pressure corresponding to set voltage.
Claims (1)
油圧モータと、その油圧モータの駆動回路に圧油
を供給する可変容量型油圧ポンプと、前記回転バ
ケツトにスラスト力を与えるスラストシリンダ
と、そのスラストシリンダ作動用の油圧ポンプと
を備えたアースドリルにおいて、前記回転バケツ
ト駆動回路の油圧を検出し、その検出圧と比較器
に設定した回転バケツト駆動回路の最高効率点に
おける油圧に相当する設定値とを比較し、検出圧
が比較器に設定した設定値より低いときはスラス
トシリンダを伸張させ、検出圧が比較器に設定し
た設定値より高いときはスラストシリンダを縮小
させ、かくして、回転バケツト駆動回路の最高効
率点付近で掘削するようにスラストシリンダを作
動させることを特徴とするアースドリルにおける
掘削作動制御方法。 ２ 回転バケツトと、その回転バケツトの駆動用
油圧モータと、その油圧モータの駆動回路に圧油
を供給する可変容量型油圧ポンプと、前記回転バ
ケツトにスラスト力を与えるスラストシリンダ
と、そのスラストシリンダ作動用の油圧ポンプと
を備えたアースドリルにおいて、前記回転バケツ
ト駆動回路の油圧を検出し、その検出圧と比較器
に設定した設定値とを比較して前記スラストシリ
ンダを制御すべくなし、かつ、前記比較器には、
正転無負荷時の回転バケツト駆動回路の油圧に相
当する第１設定値と、回転バケツト駆動回路の最
高効率点における油圧に相当する第２設定値と、
その第２設定値より若干低い油圧に相当する第３
設定値と、前記第２設定値より若干高い油圧に相
当する第４設定値とを設定し、検出圧が比較器に
設定した第１設定値と第３設定値との間のときは
スラストシリンダを伸長方向に駆動し、検出圧が
第４設定値以上のときはスラストシリンダを縮小
方向に駆動し、検出圧が比較器に設定した第３設
定値と第４設定値との間であつて、かつ第２設定
値に近づいているときにはスラストシリンダへの
供給油量を減少させながらスラストシリンダを伸
長または縮小方向に駆動し、検出圧が比較器に設
定した第３設定値と第４設定値との間であつてか
つ第２設定値より離れているときにはスラストシ
リンダへの供給油量を増大させながらスラストシ
リンダを伸長または縮小方向に駆動し、かくし
て、回転バケツト駆動回路の最高効率点付近で掘
削するようにスラストシリンダを作動させると共
に、その回転最高効率点に近づくとスラストシリ
ンダの伸縮速度を減少させることを特徴とするア
ースドリルにおける掘削作動制御方法。 ３ 回転バケツトと、その回転バケツトの駆動用
油圧モータと、その油圧モータの駆動回路に圧油
を供給する可変容量型油圧ポンプと、前記回転バ
ケツトにスラスト力を与えるスラストシリンダ
と、そのスラストシリンダ作動用の油圧ポンプと
を備えたアースドリルにおいて、前記スラストシ
リンダ作動用の油圧ポンプとして、スラストシリ
ンダのボトム室側とロッド室側との何れか一方に
接続した第１吸込吐出口と他方に接続した第２吸
込吐出口とを有し、かつ、その吸込側と吐出側と
を変換することができると共に吐出流量を可変す
ることができる両傾転式可変容量型油圧ポンプを
使用し、かつ、前記回転バケツト駆動回路の油圧
を検出し、その検出圧と比較器に設定した設定値
とを比較して前記両傾転式可変容量型油圧ポンプ
を制御すべくなし、かつ、前記比較器には、正転
無負荷時の回転バケツト駆動回路の油圧に相当す
る第１設定値と、回転バケツト駆動回路の最高効
率点における油圧に相当する第２設定値と、その
第２設定値より若干低い油圧に相当する第３設定
値と、前記第２設定値より若干高い油圧に相当す
る第４設定値とを設定し、検出圧が比較器に設定
した第１設定値と第３設定値との間のときは前記
両傾転式可変容量型油圧ポンプを最大傾転量にて
スラストシリンダ伸長方向に駆動し、検出圧が第
４設定値以上のときは前記両傾転式可変容量型油
圧ポンプをスラストシリンダ縮小方向に駆動し、
検出圧が比較器に設定した第３設定値と第４設定
値との間であつて、かつ第２設定値に近づいてい
るときには前記両傾転式可変容量型油圧ポンプを
傾転量を縮小させながらスラストシリンダ伸長ま
たは縮小方向に駆動し、検出圧が比較器に設定し
た第３設定値と第４設定値との間であつてかつ第
２設定値より離れているときには前記両傾転式可
変容量型油圧ポンプを傾転量を増大させながらス
ラストシリンダ伸長または縮小方向に駆動し、か
くして、回転バケツト駆動回路の最高効率転付近
で掘削するようにスラストシリンダを作動させる
と共に、その回路最高効率点に近づくとスラスト
シリンダの伸縮速度を減少させることを特徴とす
る特許請求の範囲第２項に記載のアースドリルに
おける掘削作動制御方法。 ４ 回転バケツトと、その回転バケツトの駆動用
油圧モータと、その油圧モータの駆動回路に圧油
を供給する可変容量型油圧ポンプと、前記回転バ
ケツトにスラスト力を与えるスラストシリンダ
と、そのスラストシリンダ作動用の油圧ポンプと
を備えたアースドリルにおいて、前記スラストシ
リンダ作動用の油圧ポンプとして、スラストシリ
ンダのボトム室側とロッド室側との何れか一方に
接続した第１吸込吐出口と他方に接続した第２吸
込吐出口とを有し、かつ、その吸込側と吐出側と
を変換することができると共に吐出流量を可変す
ることができる両傾転式可変容量型油圧ポンプを
使用し、かつ、前記回転バケツト駆動回路の油圧
を検出し、その検出圧と比較器に設定した設定値
とを比較して前記両傾転式可変容量型油圧ポンプ
を制御すべくなし、かつ、前記比較器には、正転
無負荷時の回転バケツト駆動回路の油圧に相当す
る第１設定値と、回転バケツト駆動回路の最高効
率点における油圧に相当する第２設定値と、その
第２設定値より若干低い油圧に相当する第３設定
値と、前記第２設定値より若干高い油圧に相当す
る第４設定値とを設定し、検出圧が比較器に設定
した第１設定値と第３設定値との間のときは前記
両傾転式可変容量型油圧ポンプを最大傾転量にて
スラストシリンダ伸長方向に駆動し、検出圧が第
４設定値以上のときは前記両傾転式可変容量型油
圧ポンプをスラストシリンダ縮小方向に駆動し、
検出圧が比較器に設定した第３設定値と第４設定
値との間であつて、それが上昇中のときは前記両
傾転式可変容量型油圧ポンプをスラストシリンダ
縮小方向に駆動し、検出圧が比較器に設定した第
３設定値と第４設定値との間であつてそれが下降
中のときは前記両傾転式可変容量型油圧ポンプを
スラストシリンダ伸長方向に駆動し、かつ、その
上昇下降何れの場合も、圧力変化速度に応じて両
傾転式可変容量型油圧ポンプの傾転量を調整し、
かくして、回転バケツト駆動回転の最高効率点付
近で掘削するようにスラストシリンダを作動させ
ると共に、スラストシリンダの伸縮速度を加減速
させることを特徴とするアースドリルにおける掘
削作動制御方法。[Scope of Claims] 1. A rotating bucket, a hydraulic motor for driving the rotating bucket, a variable displacement hydraulic pump that supplies pressure oil to a drive circuit of the hydraulic motor, and a thrust cylinder that provides thrust force to the rotating bucket. In an earth drill equipped with a hydraulic pump for operating the thrust cylinder, the hydraulic pressure of the rotary bucket drive circuit is detected, and the detected pressure is set in a comparator to correspond to the hydraulic pressure at the highest efficiency point of the rotary bucket drive circuit. When the detected pressure is lower than the set value set on the comparator, the thrust cylinder is extended, and when the detected pressure is higher than the set value set on the comparator, the thrust cylinder is contracted, and thus, A method for controlling excavation operation in an earth drill, characterized in that a thrust cylinder is operated so as to excavate near the highest efficiency point of a rotary bucket drive circuit. 2. A rotating bucket, a hydraulic motor for driving the rotating bucket, a variable displacement hydraulic pump that supplies pressure oil to the drive circuit of the hydraulic motor, a thrust cylinder that applies thrust force to the rotating bucket, and the thrust cylinder operation. In an earth drill equipped with a hydraulic pump for use in the earth drill, the hydraulic pressure of the rotary bucket drive circuit is detected, and the detected pressure is compared with a set value set in a comparator to control the thrust cylinder, and The comparator includes:
a first set value corresponding to the oil pressure of the rotary bucket drive circuit during normal rotation with no load; a second set value corresponding to the oil pressure at the highest efficiency point of the rotary bucket drive circuit;
The third set value corresponds to a slightly lower oil pressure than the second set value.
set value and a fourth set value corresponding to a hydraulic pressure slightly higher than the second set value, and when the detected pressure is between the first set value and the third set value set in the comparator, the thrust cylinder is driven in the extension direction, and when the detected pressure is equal to or higher than the fourth setting value, the thrust cylinder is driven in the contraction direction, and when the detected pressure is between the third setting value and the fourth setting value set in the comparator, the thrust cylinder is driven in the contraction direction. , and when it approaches the second set value, the thrust cylinder is driven in the extension or contraction direction while reducing the amount of oil supplied to the thrust cylinder, and the detected pressure is set to the third and fourth set values set in the comparator. and is further away from the second set value, the thrust cylinder is driven in the extension or contraction direction while increasing the amount of oil supplied to the thrust cylinder, and in this way, the rotation bucket drive circuit is near the highest efficiency point. A method for controlling excavation operation in an earth drill, characterized in that a thrust cylinder is operated to excavate, and the expansion and contraction speed of the thrust cylinder is reduced when the thrust cylinder approaches its rotational maximum efficiency point. 3. A rotating bucket, a hydraulic motor for driving the rotating bucket, a variable displacement hydraulic pump that supplies pressure oil to the drive circuit of the hydraulic motor, a thrust cylinder that applies thrust force to the rotating bucket, and the thrust cylinder operation. In an earth drill equipped with a hydraulic pump for operating the thrust cylinder, the hydraulic pump for operating the thrust cylinder includes a first suction and discharge port connected to either one of the bottom chamber side and the rod chamber side of the thrust cylinder, and a first suction discharge port connected to the other side. A double tilting variable displacement hydraulic pump is used, which has a second suction and discharge port, and is capable of converting between the suction side and the discharge side, and is capable of varying the discharge flow rate; The hydraulic pressure of the rotary bucket drive circuit is detected and the detected pressure is compared with a set value set in a comparator to control the double tilting variable displacement hydraulic pump, and the comparator includes: A first setting value corresponding to the oil pressure of the rotating bucket drive circuit during normal rotation with no load, a second setting value corresponding to the oil pressure at the highest efficiency point of the rotating bucket drive circuit, and an oil pressure slightly lower than the second setting value. A corresponding third setting value and a fourth setting value corresponding to an oil pressure slightly higher than the second setting value are set, and the detected pressure is between the first setting value and the third setting value set in the comparator. When the detected pressure is equal to or higher than the fourth set value, the double tilting variable displacement hydraulic pump is driven in the thrust cylinder extension direction at the maximum tilting amount. Drives the cylinder in the direction of contraction,
When the detected pressure is between the third set value and the fourth set value set in the comparator and is approaching the second set value, the amount of tilting of the double tilting variable displacement hydraulic pump is reduced. The thrust cylinder is driven in the extension or contraction direction while The variable displacement hydraulic pump is driven in the direction of extension or contraction of the thrust cylinder while increasing the amount of tilting, thus operating the thrust cylinder so as to excavate near the highest efficiency turn of the rotary bucket drive circuit, and also operating the thrust cylinder to excavate near the highest efficiency turn of the rotary bucket drive circuit. 3. The excavation operation control method in an earth drill according to claim 2, wherein the expansion and contraction speed of the thrust cylinder is reduced when the point approaches the point. 4. A rotating bucket, a hydraulic motor for driving the rotating bucket, a variable displacement hydraulic pump that supplies pressure oil to the drive circuit of the hydraulic motor, a thrust cylinder that applies thrust force to the rotating bucket, and the thrust cylinder operation. In an earth drill equipped with a hydraulic pump for operating the thrust cylinder, the hydraulic pump for operating the thrust cylinder includes a first suction and discharge port connected to either one of the bottom chamber side and the rod chamber side of the thrust cylinder, and a first suction discharge port connected to the other side. A double tilting variable displacement hydraulic pump is used, which has a second suction and discharge port, and is capable of converting between the suction side and the discharge side, and is capable of varying the discharge flow rate; The hydraulic pressure of the rotary bucket drive circuit is detected and the detected pressure is compared with a set value set in a comparator to control the double tilting variable displacement hydraulic pump, and the comparator includes: A first setting value corresponding to the oil pressure of the rotating bucket drive circuit during normal rotation with no load, a second setting value corresponding to the oil pressure at the highest efficiency point of the rotating bucket drive circuit, and an oil pressure slightly lower than the second setting value. A corresponding third setting value and a fourth setting value corresponding to an oil pressure slightly higher than the second setting value are set, and the detected pressure is between the first setting value and the third setting value set in the comparator. When the detected pressure is equal to or higher than the fourth set value, the double tilting variable displacement hydraulic pump is driven in the thrust cylinder extension direction at the maximum tilting amount. Drives the cylinder in the direction of contraction,
When the detected pressure is between a third setting value and a fourth setting value set in the comparator and is rising, driving the double tilting variable displacement hydraulic pump in a thrust cylinder contraction direction; When the detected pressure is between the third set value and the fourth set value set in the comparator and is falling, the double tilting variable displacement hydraulic pump is driven in the thrust cylinder extension direction, and In either case of rising or falling, the amount of tilting of the double tilting variable displacement hydraulic pump is adjusted according to the rate of pressure change.
Thus, the method for controlling the excavation operation in an earth drill is characterized in that the thrust cylinder is operated so as to excavate near the highest efficiency point of rotation of the rotary bucket drive, and the expansion and contraction speed of the thrust cylinder is accelerated or decelerated.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP17238684A JPS6153996A (en) | 1984-08-21 | 1984-08-21 | Control apparatus in earth drill |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP17238684A JPS6153996A (en) | 1984-08-21 | 1984-08-21 | Control apparatus in earth drill |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPS6153996A JPS6153996A (en) | 1986-03-18 |
| JPH0443157B2 true JPH0443157B2 (en) | 1992-07-15 |
Family
ID=15940956
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP17238684A Granted JPS6153996A (en) | 1984-08-21 | 1984-08-21 | Control apparatus in earth drill |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPS6153996A (en) |
Families Citing this family (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS59112891U (en) * | 1983-04-18 | 1984-07-30 | 三菱電機株式会社 | Hoist overload prevention device |
| JPH0447274Y2 (en) * | 1987-06-08 | 1992-11-09 |
-
1984
- 1984-08-21 JP JP17238684A patent/JPS6153996A/en active Granted
Also Published As
| Publication number | Publication date |
|---|---|
| JPS6153996A (en) | 1986-03-18 |
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|---|---|---|---|
| LAPS | Cancellation because of no payment of annual fees |