JP2002294758A - Hydraulic circuit for working machine - Google Patents
Hydraulic circuit for working machineInfo
- Publication number
- JP2002294758A JP2002294758A JP2001095316A JP2001095316A JP2002294758A JP 2002294758 A JP2002294758 A JP 2002294758A JP 2001095316 A JP2001095316 A JP 2001095316A JP 2001095316 A JP2001095316 A JP 2001095316A JP 2002294758 A JP2002294758 A JP 2002294758A
- Authority
- JP
- Japan
- Prior art keywords
- pressure
- circuit
- valve
- breaker
- oil
- 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.)
- Pending
Links
Classifications
-
- E—FIXED CONSTRUCTIONS
- E02—HYDRAULIC ENGINEERING; FOUNDATIONS; SOIL SHIFTING
- E02F—DREDGING; SOIL-SHIFTING
- E02F9/00—Component parts of dredgers or soil-shifting machines, not restricted to one of the kinds covered by groups E02F3/00 - E02F7/00
- E02F9/20—Drives; Control devices
- E02F9/22—Hydraulic or pneumatic drives
- E02F9/2264—Arrangements or adaptations of elements for hydraulic drives
- E02F9/2267—Valves or distributors
-
- E—FIXED CONSTRUCTIONS
- E02—HYDRAULIC ENGINEERING; FOUNDATIONS; SOIL SHIFTING
- E02F—DREDGING; SOIL-SHIFTING
- E02F3/00—Dredgers; Soil-shifting machines
- E02F3/04—Dredgers; Soil-shifting machines mechanically-driven
- E02F3/96—Dredgers; Soil-shifting machines mechanically-driven with arrangements for alternate or simultaneous use of different digging elements
- E02F3/966—Dredgers; Soil-shifting machines mechanically-driven with arrangements for alternate or simultaneous use of different digging elements of hammer-type tools
-
- E—FIXED CONSTRUCTIONS
- E02—HYDRAULIC ENGINEERING; FOUNDATIONS; SOIL SHIFTING
- E02F—DREDGING; SOIL-SHIFTING
- E02F9/00—Component parts of dredgers or soil-shifting machines, not restricted to one of the kinds covered by groups E02F3/00 - E02F7/00
- E02F9/20—Drives; Control devices
- E02F9/22—Hydraulic or pneumatic drives
- E02F9/2221—Control of flow rate; Load sensing arrangements
- E02F9/2225—Control of flow rate; Load sensing arrangements using pressure-compensating valves
- E02F9/2228—Control of flow rate; Load sensing arrangements using pressure-compensating valves including an electronic controller
-
- E—FIXED CONSTRUCTIONS
- E02—HYDRAULIC ENGINEERING; FOUNDATIONS; SOIL SHIFTING
- E02F—DREDGING; SOIL-SHIFTING
- E02F9/00—Component parts of dredgers or soil-shifting machines, not restricted to one of the kinds covered by groups E02F3/00 - E02F7/00
- E02F9/20—Drives; Control devices
- E02F9/22—Hydraulic or pneumatic drives
- E02F9/2278—Hydraulic circuits
- E02F9/2285—Pilot-operated systems
Landscapes
- Engineering & Computer Science (AREA)
- Mining & Mineral Resources (AREA)
- Civil Engineering (AREA)
- General Engineering & Computer Science (AREA)
- Structural Engineering (AREA)
- Mechanical Engineering (AREA)
- Physics & Mathematics (AREA)
- Fluid Mechanics (AREA)
- Operation Control Of Excavators (AREA)
- Fluid-Pressure Circuits (AREA)
Abstract
Description
【０００１】[0001]
【発明の属する技術分野】本発明は、作業機アームの先
端部に設けられたフロントリンク機構にブレーカを含む
複数の作業機を交換可能に取り付けられる油圧ショベル
の作業機用の油圧回路に関する。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a hydraulic circuit for a working machine of a hydraulic shovel in which a plurality of working machines including a breaker can be exchangeably mounted on a front link mechanism provided at a distal end of a working machine arm.
【０００２】[0002]
【従来の技術】油圧ショベルの作業機アームの先端部に
設けられたフロントリンク機構には、各種の作業機が着
脱可能に連結される。作業機の代表例としてはバケット
があるが、その他にブレーカ、クラッシャ、ブレード、
２ピースブーム、回転アーム等がある。2. Description of the Related Art Various working machines are detachably connected to a front link mechanism provided at the tip of a working machine arm of a hydraulic shovel. A typical example of a work machine is a bucket. In addition, a breaker, a crusher, a blade,
There are a two-piece boom, a rotating arm and the like.
【０００３】図２に従来の油圧ショベルの油圧回路の一
例を示す。図２において、１個あるいは複数個の可変容
量型油圧ポンプ１（本例では１個）の吐出回路２には方
向切換弁群６が接続され、又、方向切換弁群６はドレン
回路３と接続している。４はオイルタンク、５はストレ
ーナである。方向切換弁群６は方向切換弁６ａ〜６ｇよ
りなり、方向切換弁６ａは図示しない作業機アームシリ
ンダに、方向切換弁６ｂは図示しない右走行モータに、
方向切換弁６ｃは図示しない旋回モータにそれぞれ接続
している。又、方向切換弁６ｄは図示しない作業機ブー
ムシリンダに、方向切換弁６ｅは左走行モータに、方向
切換弁６ｆは図示しない作業機バケットシリンダにそれ
ぞれ接続している。そして、方向切換弁６ｇは、図示し
ないフロントリンク機構に着脱自在なブレーカやクラッ
シャ等の作業機１０に、一側回路１１及び他側回路１２
を介して接続している。方向切換弁６ｇはＡ，Ｂ，Ｃの
３位置を有し、Ａ位置とＣ位置とで回路が切り換わり、
Ｂ位置は保持である。Ａ位置とＣ位置では吐出回路２上
に絞り７，７が設けられ、吐出回路２上にはロードセン
シング弁８が設けられていてロードセンシング制御回路
を構成している。なお、本図では方向切換弁６ｇ以外は
回路構成の図示は省略してあるが、他の方向切換弁６ａ
〜６ｆも同様の構成となっている。一側回路１１及び他
側回路１２にはそれぞれ高圧安全弁１３，１３（例えば
リリーフ圧２５０kg/cm2）が設けられている。一側回路
１１上には、作業機１０と方向切換弁６ｇとを接続する
回路と、作業機１０とオイルタンク４とを接続するドレ
ン回路３ａとを切り換える手動のロータリ式の第１回路
切換弁6０が設けられている。他側回路１２上には、低
圧安全弁６１（例えばリリーフ圧２１０kg/cm2）と接続
する回路６２との回路の開閉を切り換える手動のロータ
リ式の第２回路切換弁６３が設けられている。パイロッ
ト圧力比例制御弁２０のパイロット元圧回路２２は、可
変容量型油圧ポンプ(1)の吐出回路２と自己減圧弁２３
を介して接続している。パイロット圧力比例制御弁２０
と方向切換弁６ｇとは、第１パイロット圧回路２４と第
２パイロット回路２５とにより接続している。パイロッ
ト圧力制御弁２０の操作レバー２１を操作すると、操作
量に比例して第１パイロット圧回路２４又は第２パイロ
ット圧回路２５のパイロット圧が変化し、方向切換弁６
ｇのストロークを制御する。これにより、作動油の流量
はパイロット圧に比例して変わるようになっている。パ
イロット圧力比例制御弁２０の操作レバー２１には操作
ペダル２６が取り付けられており、操作ペダル２６の下
方にはペダルストローク調整用の調整ボルト６４が設け
られている。すなわち、ペダルストロークを調整するこ
とにより操作レバー２１の操作量が調整され、作動油の
流量が調整される。FIG. 2 shows an example of a hydraulic circuit of a conventional hydraulic shovel. In FIG. 2, a directional control valve group 6 is connected to a discharge circuit 2 of one or a plurality of variable displacement hydraulic pumps 1 (one in this example). Connected. 4 is an oil tank and 5 is a strainer. The directional control valve group 6 includes directional control valves 6a to 6g. The directional control valve 6a is provided to a working machine arm cylinder (not shown), the directional control valve 6b is provided to a right traveling motor (not shown),
The direction switching valves 6c are respectively connected to turning motors (not shown). The direction switching valve 6d is connected to a working machine boom cylinder (not shown), the direction switching valve 6e is connected to a left running motor, and the direction switching valve 6f is connected to a working machine bucket cylinder (not shown). The directional control valve 6g is connected to a working machine 10 such as a breaker or a crusher that is detachable from a front link mechanism (not shown) by a one-side circuit 11 and another-side circuit 12.
Connected through. The directional control valve 6g has three positions A, B and C, and the circuit is switched between the position A and the position C.
Position B is holding. At positions A and C, throttles 7, 7 are provided on the discharge circuit 2 and a load sensing valve 8 is provided on the discharge circuit 2 to constitute a load sensing control circuit. Although the circuit configuration is not shown in the figure except for the direction switching valve 6g, the other direction switching valves 6a
To 6f have the same configuration. The one-side circuit 11 and the other-side circuit 12 are provided with high-pressure safety valves 13, 13 (for example, a relief pressure of 250 kg / cm 2 ). On one side circuit 11, a manual rotary first circuit switching valve for switching between a circuit connecting working machine 10 and direction switching valve 6g and a drain circuit 3a connecting working machine 10 and oil tank 4 60 are provided. On the other side circuit 12, a manual rotary type second circuit switching valve 63 for switching between opening and closing of a circuit with a circuit 62 connected to a low pressure safety valve 61 (for example, a relief pressure of 210 kg / cm 2 ) is provided. The pilot source pressure circuit 22 of the pilot pressure proportional control valve 20 includes the discharge circuit 2 of the variable displacement hydraulic pump (1) and the self-reducing valve 23.
Connected through. Pilot pressure proportional control valve 20
The direction switching valve 6g is connected by a first pilot pressure circuit 24 and a second pilot circuit 25. When the operating lever 21 of the pilot pressure control valve 20 is operated, the pilot pressure of the first pilot pressure circuit 24 or the second pilot pressure circuit 25 changes in proportion to the operation amount, and the direction switching valve 6
Control the stroke of g. Thus, the flow rate of the hydraulic oil changes in proportion to the pilot pressure. An operation pedal 26 is attached to the operation lever 21 of the pilot pressure proportional control valve 20, and an adjustment bolt 64 for adjusting a pedal stroke is provided below the operation pedal 26. That is, by adjusting the pedal stroke, the operation amount of the operation lever 21 is adjusted, and the flow rate of the hydraulic oil is adjusted.
【０００４】次に、作業機１０の作動について説明す
る。図２はブレーカ以外の作業機を取り付けた場合の回
路を示している。すなわち、一側回路１１は作業機１０
と方向切換弁６ｇとを接続し、一側回路１１及び他側回
路１２は高圧安全弁１３，１３に接続している。作業機
１０を作動する場合には、操作ペダル２６を前後方向に
踏み込んでパイロット圧力比例制御弁２０を操作する。
この場合、操作ペダル２６の微調整は困難なため、一般
には操作ペダル２６はストロークエンドまで踏み込まれ
る。操作ペダル２６のストロークに比例してパイロット
油圧は方向切換弁６ｇに作用し、Ａ位置又はＣ位置に移
動する。一般の作業機の場合には、調整ボルト６４は短
く調整され、操作ペダル２６のストロークは十分に大き
く設定され、方向切換弁６ｇの流量は最大の状態で使用
される。可変容量型油圧ポンプ１の圧油は作業機１０に
送られ、戻り油は方向切換弁６ｇを介してオイルタンク
４に戻される。本回路は前述のようにロードセンシング
制御回路を構成しているため、動力損失の少ない、効率
的な作動が行われる。Next, the operation of the work machine 10 will be described. FIG. 2 shows a circuit when a working machine other than a breaker is mounted. That is, the one side circuit 11 is
And the direction switching valve 6g, and the one-side circuit 11 and the other-side circuit 12 are connected to the high-pressure safety valves 13, 13. When operating the work implement 10, the operation pedal 26 is depressed in the front-rear direction to operate the pilot pressure proportional control valve 20.
In this case, since fine adjustment of the operation pedal 26 is difficult, the operation pedal 26 is generally depressed to the stroke end. The pilot hydraulic pressure acts on the direction switching valve 6g in proportion to the stroke of the operation pedal 26, and moves to the A position or the C position. In the case of a general work machine, the adjustment bolt 64 is adjusted to be short, the stroke of the operation pedal 26 is set to be sufficiently large, and the flow rate of the directional control valve 6g is used at the maximum. The pressure oil of the variable displacement hydraulic pump 1 is sent to the work machine 10, and the return oil is returned to the oil tank 4 via the direction switching valve 6g. Since this circuit constitutes the load sensing control circuit as described above, efficient operation with little power loss is performed.
【０００５】次に、作業機１０がブレーカ１０ａの場合
の回路及び作動について説明する。ブレーカ１０ａの場
合には、外部からの塵埃や異物等が侵入する恐れがある
ため、戻り油は方向切換弁６ｇを介さずに直接オイルタ
ンク４に戻す必要がある。又、許容圧力が他の作業機の
許容圧力より低い場合や、必要流量が少ない場合が多
い。図３は作業機１０をブレーカ１０ａに付け替えた場
合のブレーカ回路部分の油圧回路図である。図３におい
て、第１回路切換弁６０を切り換えてブレーカ１０ａと
オイルタンク４とをドレン回路３ａを介して直接接続
し、第２回路切換弁６３を切り換えて他側回路１２と低
圧安全弁６１とを接続する。又、操作ペダル２６の調整
ボルト６４のセット長さを長く調整して操作ペダル２６
のストロークを調整し、ブレーカ１０ａへの流量をブレ
ーカ１０ａの必要流量に合わせて低減する。これにより
ブレーカ１０ａへの圧油の供給量及び最高圧力は低減さ
れ、ブレーカ１０ａからの戻り油は方向切換弁６ｇを介
さずに、直接オイルタンク４に戻される。Next, the circuit and operation when the work machine 10 is the breaker 10a will be described. In the case of the breaker 10a, since there is a possibility that dust or foreign matter from the outside may enter, it is necessary to return the return oil directly to the oil tank 4 without passing through the direction switching valve 6g. Also, the allowable pressure is often lower than the allowable pressure of other working machines, or the required flow rate is often small. FIG. 3 is a hydraulic circuit diagram of a breaker circuit portion when the work machine 10 is replaced with a breaker 10a. In FIG. 3, the first circuit switching valve 60 is switched to directly connect the breaker 10a and the oil tank 4 via the drain circuit 3a, and the second circuit switching valve 63 is switched to connect the other circuit 12 and the low-pressure safety valve 61. Connecting. Further, the set length of the adjustment bolt 64 of the operation pedal 26 is adjusted to be longer, and the operation pedal 26 is adjusted.
Is adjusted to reduce the flow rate to the breaker 10a in accordance with the required flow rate of the breaker 10a. As a result, the supply amount and the maximum pressure of the pressure oil to the breaker 10a are reduced, and the return oil from the breaker 10a is returned directly to the oil tank 4 without passing through the direction switching valve 6g.
【０００６】[0006]
【発明が解決しようとする課題】しかしながら、上記構
成においては、ブレーカと他の作業機とを交換する都
度、第１回路切換弁６０及び第２回路切換弁６３を手動
で切り換える必要がある。又、操作ペダル２６の調整ボ
ルト６４を手で調整しなければならず、作業が煩雑だと
いう問題点がある。However, in the above configuration, it is necessary to manually switch the first circuit switching valve 60 and the second circuit switching valve 63 each time the breaker is replaced with another working machine. In addition, there is a problem that the adjustment bolt 64 of the operation pedal 26 must be manually adjusted, and the operation is complicated.
【０００７】本発明は、上記の問題点に着目してなされ
たものであり、ブレーカ等の必要流量や最高許容圧力が
他の作業機と異なる作業機を使用する場合、容易に、か
つ確実に、圧力、流量あるいは回路の切換が行える作業
機用の油圧回路を提供することを目的としている。[0007] The present invention has been made in view of the above problems, and when using a working machine whose required flow rate and maximum allowable pressure of a breaker or the like are different from those of other working machines, it is easy and reliable. It is an object of the present invention to provide a hydraulic circuit for a working machine capable of switching between pressure, flow rate and circuit.
【０００８】[0008]
【課題を解決するための手段、作用及び効果】上記の目
的を達成するために、第１発明は、油圧ポンプからの圧
油の供給を制御する複数個の方向切換弁を有し、フロン
トリンク機構には、前記方向切換弁からの圧油の供給を
受けて作動する、少なくともブレーカを含む複数の作業
機を、交換自在に取り付け可能とした油圧ショベルの作
業機用の油圧回路において、前記方向切換弁と作業機と
を接続する２本の送油回路のうちの、一側回路上に設け
られ、ブレーカを取り付けたときに、ブレーカからの戻
り油を前記方向切換弁を介さずに直接オイルタンクに戻
すように、接続をドレン回路に切り換える３方向切換弁
と、前記方向切換弁と作業機とを接続する２本の送油回
路のうちの、ブレーカを取り付けたときにブレーカに圧
油を供給する他側回路に設けられ、設定圧力を高低２段
に切り換え可能な圧力可変式安全弁と、運転室内に設け
られ、前記３方向切換弁と圧力可変式安全弁とを連動し
て切換可能なモード切換手段とを備えた構成としてい
る。In order to achieve the above object, a first invention has a plurality of directional control valves for controlling the supply of hydraulic oil from a hydraulic pump, and a front link. In the hydraulic circuit for a working machine of a hydraulic shovel, the mechanism is configured such that a plurality of working machines including at least a breaker, which operate by receiving a supply of pressure oil from the direction switching valve, can be exchangeably mounted. Of the two oil supply circuits connecting the switching valve and the working machine, provided on one side circuit, when the breaker is attached, the return oil from the breaker is directly supplied to the oil without passing through the direction switching valve. A three-way switching valve that switches the connection to a drain circuit so as to return to the tank, and pressure oil is supplied to the breaker when the breaker is installed, of the two oil supply circuits that connect the directional switching valve and the working machine. Other side to supply A pressure-variable safety valve provided on the road and capable of switching the set pressure between high and low stages; and a mode switching means provided in the operator's cab and capable of switching the three-way switching valve and the pressure-variable safety valve in conjunction with each other. It is provided with a configuration.
【０００９】第１発明によると、ブレーカからの戻り油
を直接作動油タンクに戻す回路に切り換えるための３方
向切換弁と、圧力可変式安全弁とを連動して切換可能な
モード切換手段を運転室内に設けた。そのため、ブレー
カを取り付けたときに、運転室内で容易に、戻り油を作
動油タンクに直接戻す回路への切り換えと、圧力可変式
安全弁の圧力の低圧への切換が可能であり、切換が確実
であると共に、作業性が向上する。According to the first aspect of the present invention, the mode switching means for switching the three-way switching valve for switching the return oil from the breaker directly to the circuit for returning the oil to the hydraulic oil tank and the pressure-variable safety valve in a cab is provided. Provided. Therefore, when the breaker is installed, it is possible to easily switch to a circuit that returns the return oil directly to the hydraulic oil tank and to switch the pressure of the variable pressure safety valve to a low pressure in the operator's cab. At the same time, workability is improved.
【００１０】第２発明は、油圧ポンプからの圧油の供給
を制御する複数個のパイロット油圧作動式の方向切換弁
のストロークを、パイロット圧力比例制御弁からのパイ
ロット圧力により制御し、圧油の流量を調整するパイロ
ット圧力比例制御式油圧装置を有し、フロントリンク機
構には、前記方向切換弁から供給される圧油により作動
する、少なくともブレーカを含む複数の作業機を、交換
自在に取り付け可能とした油圧ショベルの作業機用の油
圧回路において、前記方向切換弁と作業機とを接続する
２本の送油回路のうちの、一側回路上に設けられ、ブレ
ーカを取り付けたときに、ブレーカからの戻り油を前記
方向切換弁を介さずに直接オイルタンクに戻すように、
接続をドレン回路に切り換える３方向切換弁と、前記方
向切換弁の流量調整をするために、パイロット圧力比例
制御弁のパイロット元圧力を制御する電磁比例圧力制御
弁と、運転室内に設けられ、前記３方向切換弁を切り換
えるモード切換手段と、運転室内に設けられ、前記電磁
比例圧力制御弁を制御する流量調整手段とを備えた構成
としている。In a second aspect, the strokes of a plurality of pilot hydraulically operated directional control valves for controlling the supply of hydraulic oil from a hydraulic pump are controlled by the pilot pressure from a pilot pressure proportional control valve, and It has a pilot pressure proportional control type hydraulic device for adjusting the flow rate, and a plurality of working machines including at least a breaker, which are operated by pressure oil supplied from the directional switching valve, can be attached to the front link mechanism in a replaceable manner. A hydraulic circuit for a working machine of a hydraulic shovel, which is provided on one side circuit of two oil supply circuits for connecting the directional switching valve and the working machine, and that when the breaker is attached, To return the return oil from directly to the oil tank without passing through the direction switching valve,
A three-way switching valve for switching connection to a drain circuit, an electromagnetic proportional pressure control valve for controlling a pilot source pressure of a pilot pressure proportional control valve for adjusting a flow rate of the directional switching valve, and A mode switching means for switching the three-way switching valve and a flow rate adjusting means provided in the cab and controlling the electromagnetic proportional pressure control valve are provided.
【００１１】第２発明によると、パイロット圧力比例制
御式油圧装置において、ブレーカからの戻り油を直接作
動油タンクに戻す回路に切り換えるための３方向切換弁
と、パイロット圧力比例制御弁のパイロット元圧力を制
御する電磁比例圧力制御弁とを設けた。そして、３方向
切換弁を切り換える作業モード切換手段と、電磁比例圧
力制御弁の制御手段とを運転室内に設けた。そのため、
ブレーカを取り付けたときに、運転室内で容易に、戻り
油を作動油タンクに直接戻す回路に切り換えると共に、
パイロット元圧力を制御して作動油の流量を制御するこ
とができ、作業性が向上する。According to the second aspect of the present invention, in the hydraulic device of the pilot pressure proportional control type, a three-way switching valve for switching the return oil from the breaker to a circuit for returning the oil directly to the hydraulic oil tank, and a pilot source pressure of the pilot pressure proportional control valve And an electromagnetic proportional pressure control valve. The operation mode switching means for switching the three-way switching valve and the control means for the electromagnetic proportional pressure control valve are provided in the cab. for that reason,
When the breaker is installed, the return oil can be easily switched to the circuit that returns the return oil directly to the hydraulic oil tank in the cab,
By controlling the pilot source pressure, the flow rate of hydraulic oil can be controlled, and workability is improved.
【００１２】第３発明は、第２発明において、前記方向
切換弁と作業機とを接続する２本の送油回路のうちの、
ブレーカが取り付けられたときにブレーカに圧油を供給
する他側回路に設けられ、設定圧力を高低２段に切換可
能な圧力可変式安全弁と、運転室内に設けられ、前記３
方向切換弁と前記圧力可変式安全弁とを連動して切換可
能なモード切換手段とを備えた構成としている。According to a third aspect of the present invention, in the second aspect, of the two oil feeding circuits for connecting the directional control valve and the working machine,
A pressure-variable safety valve that is provided in the other side circuit that supplies pressure oil to the breaker when the breaker is mounted, and that is capable of switching a set pressure between high and low levels;
A mode switching means is provided which can switch the direction switching valve and the pressure variable safety valve in an interlocked manner.
【００１３】第３発明によると、ブレーカからの戻り油
を直接作動油タンクに戻す回路に切り換えるための３方
向切換弁と、圧力可変安全弁とを同時に切換可能なモー
ド切換手段を運転室内に設けた。又、流量調整手段を運
転室内に設けた。そのため、ブレーカを取り付けたとき
に、運転室内で容易に、戻り油を作動油タンクに直接戻
す回路に切り換えると同時に、圧力可変式安全弁の圧力
を低圧に切換可能であり、又、容易に流量調整が可能で
あり、作業性が向上する。According to the third aspect of the invention, the three-way switching valve for switching the return oil from the breaker to the circuit for directly returning the oil to the hydraulic oil tank and the mode switching means capable of simultaneously switching the pressure variable safety valve are provided in the cab. . Further, the flow rate adjusting means is provided in the cab. Therefore, when the breaker is installed, it is possible to easily switch the circuit to return the return oil directly to the hydraulic oil tank in the operator's cab, and at the same time, switch the pressure of the pressure-variable safety valve to low pressure, and easily adjust the flow rate. Is possible, and workability is improved.
【００１４】[0014]
【発明の実施の形態】以下に本発明に係る作業機用の油
圧回路の実施形態について、図面を参照して詳述する。DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of a hydraulic circuit for a working machine according to the present invention will be described below in detail with reference to the drawings.
【００１５】図１は油圧ショベルの油圧回路図であり、
図２に示す従来のものと同一部材には同一符号を付して
説明は省略し、異なる部分についてのみ説明する。方向
切換弁６ｇと作業機１０とを接続する２本の送油回路の
うちの、他側回路１２上には、リリーフ圧力を例えば２
５０kg/cm2と２１０kg/cm2との２段に切換可能な圧力可
変式安全弁３０が設けられている。圧力可変式安全弁３
０は安全弁３１の下方に安全弁バネ３２のセット荷重を
変更するピストン３３を設け、ピストン３３をパイロッ
ト圧により下方に移動させて安全弁バネ３２のセット荷
重を下げ、安全弁圧力を低下させるようになっている。
方向切換弁６ｇと作業機１０とを接続する２本の送油回
路のうちの一側回路１１上には、Ｄ位置とＥ位置とを有
する３方向切換弁３４が設けられ、Ｄ位置では作業機１
０と方向切換弁６ｇとは接続し、Ｅ位置では作業機１０
とオイルタンク４とをドレン回路３ａを介して直接接続
するようになっている。３方向切換弁３４はパイロット
圧により作動する。パイロット元圧回路２２と、圧力可
変式安全弁３０及び３方向切換弁３４とを接続するパイ
ロット回路３５上には、電磁回路切換弁４５が設けられ
ている。電磁回路切換弁４５は、Ｆ位置とＧ位置とを有
し、Ｆ位置ではパイロット回路３５はドレン回路３ｂに
接続し、Ｇ位置ではパイロット回路３５はパイロット元
圧回路２２と接続する。バイロット元圧回路２２上に
は、流量制御用の電磁比例圧力制御弁５１が設けられて
いる。電磁比例圧力制御弁５１は印加される電流値に比
例してパイロット元圧を増減可能であり、パイロット元
圧を調整することにより、方向切換弁６ｇのストローク
を調整し、流量を調整することが可能である。電磁回路
切換弁４５と電磁比例圧力制御弁５１とは制御装置４１
に接続し、制御装置４１は、運転室内に設けられたディ
スプレイ４３と操作ボタン４４とを有する操作盤４２と
接続しており、モード切換手段４０を構成している。
又、制御装置４１は、電磁比例圧力制御弁５１と接続し
ており、操作盤４２と合わせて流量調整手段５０を構成
している。FIG. 1 is a hydraulic circuit diagram of a hydraulic excavator.
The same members as those of the related art shown in FIG. 2 are denoted by the same reference numerals, description thereof will be omitted, and only different portions will be described. The relief pressure is set to, for example, 2 on the other side circuit 12 of the two oil supply circuits connecting the direction switching valve 6g and the work implement 10.
A variable-pressure safety valve 30 is provided which can be switched between two stages of 50 kg / cm 2 and 210 kg / cm 2 . Variable pressure relief valve 3
0 is provided below the safety valve 31 with a piston 33 for changing the set load of the safety valve spring 32. The piston 33 is moved downward by the pilot pressure to reduce the set load of the safety valve spring 32 and lower the safety valve pressure. I have.
A three-way switching valve 34 having a D position and an E position is provided on one side circuit 11 of the two oil supply circuits connecting the directional switching valve 6g and the work implement 10, and the work is performed in the D position. Machine 1
0 and the directional control valve 6g are connected, and the work machine 10
And the oil tank 4 are directly connected via a drain circuit 3a. The three-way switching valve 34 operates by pilot pressure. An electromagnetic circuit switching valve 45 is provided on the pilot circuit 35 that connects the pilot source pressure circuit 22 with the variable pressure safety valve 30 and the three-way switching valve 34. The electromagnetic circuit switching valve 45 has an F position and a G position. At the F position, the pilot circuit 35 is connected to the drain circuit 3b, and at the G position, the pilot circuit 35 is connected to the pilot source pressure circuit 22. An electromagnetic proportional pressure control valve 51 for controlling the flow rate is provided on the bi-lot source pressure circuit 22. The electromagnetic proportional pressure control valve 51 can increase or decrease the pilot source pressure in proportion to the applied current value. By adjusting the pilot source pressure, the stroke of the direction switching valve 6g can be adjusted and the flow rate can be adjusted. It is possible. The electromagnetic circuit switching valve 45 and the electromagnetic proportional pressure control valve 51
The control device 41 is connected to an operation panel 42 having a display 43 and operation buttons 44 provided in the driver's cab, and constitutes a mode switching means 40.
Further, the control device 41 is connected to the electromagnetic proportional pressure control valve 51, and constitutes a flow rate adjusting means 50 together with the operation panel 42.
【００１６】次に、作動について説明する。本図はブレ
ーカ以外の作業機１０を取り付けた場合を示している。
作業者は操作盤４２の操作ボタン４４を操作してブレー
カ以外の作業機モードを指定すると共に、ディスプレイ
４３の表示を見ながら方向切換弁６ｇの流量を最大に指
定する。制御装置４１はその指令信号を入力し、電磁回
路切換弁４５に制御信号を出力してＦ位置に切り換える
と共に、電磁比例圧力制御弁５１を最大流量位置にす
る。それにより圧力可変式安全弁３０は高圧となり、３
方向切換弁３４はＤ位置となって作業機１０と方向切換
弁６ｇとを一側回路１１を介して接続する。したがっ
て、作業者は操作ペダル２６を前後方向に踏み込むこと
により方向切換弁６ｇはＡ，Ｂ，Ｃの各位置に切り換わ
り、作業機１０は作動する。作業機１０の戻り油は方向
切換弁６ｇを介してオイルタンク４にドレンされる。Next, the operation will be described. This figure shows a case where a working machine 10 other than a breaker is attached.
The operator operates the operation button 44 of the operation panel 42 to designate a work machine mode other than the breaker, and designates the flow rate of the direction switching valve 6g to the maximum while watching the display on the display 43. The control device 41 inputs the command signal, outputs a control signal to the electromagnetic circuit switching valve 45 to switch to the F position, and sets the electromagnetic proportional pressure control valve 51 to the maximum flow position. As a result, the pressure variable safety valve 30 becomes high pressure,
The directional control valve 34 is in the D position and connects the work implement 10 and the directional control valve 6g via the one-side circuit 11. Therefore, when the operator steps on the operation pedal 26 in the front-rear direction, the direction switching valve 6g switches to each of the positions A, B, and C, and the work implement 10 operates. The return oil of the work machine 10 is drained to the oil tank 4 via the direction switching valve 6g.
【００１７】次に、作業機１０がブレーカ１０ａの場合
の作動について説明する。作業者は操作盤４２の操作ボ
タン４４を操作してブレーカモードを指定すると共に、
ディスプレイ４３に数値を表示させながら定められた作
動油流量を指定する。制御装置４１は指令信号を入力し
て所定の演算をし、電磁回路切換弁４５をＧ位置に切り
換えると共に、電磁比例圧力制御弁５１に所定の電流値
を印加する。パイロット元圧回路２２の油圧は圧力可変
式安全弁３０を低圧側に切り換えると共に、３方向切換
弁３４をＥ位置に切り換えてブレーカ１０ａとドレン回
路３ａとを接続する。又、電磁比例圧力制御弁５１はパ
イロット元圧回路２２の圧力を電流値に対応して低下さ
せる。作業者が操作ペダル２６を前方に踏み込むと、パ
イロット圧は第１パイロット回路２４に加えられて方向
切換弁６ｇはＣ位置に切り換わり、可変容量型油圧ポン
プ１の圧油はブレーカ１０ａに供給される。方向切換弁
６ｇのストロークは調整され、圧油の供給量は予め指定
された流量となる。ブレーカ１０ａの戻り油は３方向切
換弁３４を経て直接オイルタンク４にドレンされる。操
作ペダル２６を後方に踏み込んだ場合には、方向切換弁
６ｇはＡ位置に切り換わるが、３方向切換弁３４がＥ位
置にあるため、回路は閉じられており、ブレーカ１０ａ
は作動しない。Next, the operation when the work machine 10 is the breaker 10a will be described. The operator operates the operation button 44 of the operation panel 42 to designate the breaker mode,
While the numerical value is displayed on the display 43, the determined hydraulic oil flow rate is designated. The control device 41 inputs a command signal, performs a predetermined calculation, switches the electromagnetic circuit switching valve 45 to the G position, and applies a predetermined current value to the electromagnetic proportional pressure control valve 51. The hydraulic pressure of the pilot source pressure circuit 22 switches the pressure variable safety valve 30 to the low pressure side and switches the three-way switching valve 34 to the E position to connect the breaker 10a and the drain circuit 3a. Further, the electromagnetic proportional pressure control valve 51 reduces the pressure of the pilot source pressure circuit 22 in accordance with the current value. When the operator steps on the operation pedal 26 forward, the pilot pressure is applied to the first pilot circuit 24, the direction switching valve 6g is switched to the C position, and the pressure oil of the variable displacement hydraulic pump 1 is supplied to the breaker 10a. You. The stroke of the direction switching valve 6g is adjusted, and the supply amount of the pressure oil becomes the flow rate specified in advance. The return oil from the breaker 10a is drained directly to the oil tank 4 via the three-way switching valve 34. When the operation pedal 26 is depressed backward, the direction switching valve 6g switches to the position A, but since the three-way switching valve 34 is at the position E, the circuit is closed and the breaker 10a
Does not work.
【００１８】本発明の作業機用の油圧回路は上記のよう
な構成としたため、作業機をブレーカあるいはブレーカ
以外のものと付け替えた場合、作業者は運転室内で操作
盤４２を操作するのみでドレン回路の切り換え、安全弁
圧力の低減、圧油供給流量の調整を、確実に、容易に行
え、作業性が向上する。Since the hydraulic circuit for the working machine according to the present invention has the above-described structure, when the working machine is replaced with a breaker or something other than a breaker, the operator only needs to operate the operation panel 42 in the cab to drain. Switching of the circuit, reduction of the safety valve pressure, and adjustment of the pressure oil supply flow rate can be performed reliably and easily, and workability is improved.
【００１９】なお、本実施形態では、油圧回路はロード
センシング制御回路となっているが、その他の回路であ
っても良い。In this embodiment, the hydraulic circuit is a load sensing control circuit, but may be another circuit.
【図１】本発明の作業機用の油圧回路を有する油圧ショ
ベルの油圧回路図である。FIG. 1 is a hydraulic circuit diagram of a hydraulic shovel having a hydraulic circuit for a working machine according to the present invention.
【図２】従来の一例の作業機用の油圧回路を有する油圧
ショベルの、ブレーカ以外の作業機用の油圧回路図であ
る。FIG. 2 is a hydraulic circuit diagram for a working machine other than a breaker of a hydraulic shovel having a hydraulic circuit for a working machine according to a conventional example.
【図３】従来の一例の作業機用の油圧回路を有する圧油
圧ショベルの、ブレーカ用の油圧回路図である。FIG. 3 is a hydraulic circuit diagram for a breaker of a conventional hydraulic excavator having a hydraulic circuit for a working machine.
１…可変容量型油圧ポンプ、２…吐出回路、３，３ａ，
３ｂ…ドレン回路、４…オイルタンク、５…ストレー
ナ、６…方向切換弁群、６ａ〜６ｇ…方向切換弁、１０
…作業機、１０ａ…ブレーカ、１１…一側回路、１２…
他側回路、１３…高圧安全弁、２０…パイロット圧力比
例制御弁、２１…操作レバー、２２パイロット元圧回
路、２３…自己減圧弁、２４…第１パイロット回路、２
５…第２パイロット回路、２６…操作ペダル、３０…圧
力可変式安全弁、３１…安全弁、３２…安全弁バネ、３
３…ピストン、３４…３方向切換弁、３５…パイロット
回路、４０…モード切換手段、４１…制御装置、４２…
操作盤、４３…ディスプレイ、４４…操作ボタン４５…
電磁回路切換弁、５０…流量調整手段、５１…電磁比例
圧力制御弁。1. Variable displacement hydraulic pump, 2. Discharge circuit, 3, 3a,
3b: drain circuit, 4: oil tank, 5: strainer, 6: directional switching valve group, 6a to 6g: directional switching valve, 10
... Work machine, 10a ... breaker, 11 ... one side circuit, 12 ...
Other side circuit, 13 ... High pressure safety valve, 20 ... Pilot pressure proportional control valve, 21 ... Operation lever, 22 Pilot source pressure circuit, 23 ... Self pressure reducing valve, 24 ... First pilot circuit, 2
5 ... second pilot circuit, 26 ... operating pedal, 30 ... pressure variable safety valve, 31 ... safety valve, 32 ... safety valve spring, 3
DESCRIPTION OF SYMBOLS 3 ... Piston, 34 ... 3-way switching valve, 35 ... Pilot circuit, 40 ... Mode switching means, 41 ... Control device, 42 ...
Operation panel, 43 ... Display, 44 ... Operation buttons 45 ...
Electromagnetic circuit switching valve, 50: flow rate adjusting means, 51: electromagnetic proportional pressure control valve.
───────────────────────────────────────────────────── フロントページの続き Ｆターム(参考） 2D003 AA01 AB04 BA02 BB02 BB03 CA06 DA03 DA04 EA00 3H089 AA04 AA21 AA60 AA74 BB15 CC11 DA03 DB03 DB43 EE22 EE26 EE31 GG02 JJ02 ──────────────────────────────────────────────────続 き Continued on the front page F term (reference) 2D003 AA01 AB04 BA02 BB02 BB03 CA06 DA03 DA04 EA00 3H089 AA04 AA21 AA60 AA74 BB15 CC11 DA03 DB03 DB43 EE22 EE26 EE31 GG02 JJ02
Claims (3)
複数個の方向切換弁(6a〜6g)を有し、フロントリンク機
構には、前記方向切換弁(6g)からの圧油の供給を受けて
作動する、少なくともブレーカ(10a)を含む複数の作業
機(10)を、交換自在に取り付け可能とした油圧ショベル
の作業機用の油圧回路において、前記方向切換弁(6g)と
作業機(10)とを接続する２本の送油回路のうちの、一側
回路(11)上に設けられ、ブレーカ(10a)を取り付けたと
きに、ブレーカ(10a)からの戻り油を前記方向切換弁(6
g)を介さずに直接オイルタンク(4)に戻すように、接続
をドレン回路(3a)に切り換える３方向切換弁(34)と、前
記方向切換弁(6g)と作業機(10)とを接続する２本の送油
回路のうちの、ブレーカ(10a)を取り付けたときに、ブ
レーカ(10a)に圧油を供給する他側回路(12)に設けら
れ、設定圧力を高低２段に切り換え可能な圧力可変式安
全弁(30)と、運転室内に設けられ、前記３方向切換弁(3
4)と圧力可変式安全弁(30)とを連動して切換可能なモー
ド切換手段(40)とを備えたことを特徴とする作業機用の
油圧回路。1. A plurality of directional control valves (6a to 6g) for controlling supply of hydraulic oil from a hydraulic pump, and supply of hydraulic oil from the directional control valve (6g) to a front link mechanism. In the hydraulic circuit for a working machine of a hydraulic shovel, which can be interchangeably mounted with a plurality of working machines (10) including at least a breaker (10a), the direction switching valve (6g) and the working machine When the breaker (10a) is installed, the return oil from the breaker (10a) is switched to the above-mentioned direction when the breaker (10a) is installed. Valve (6
g) The three-way switching valve (34) for switching the connection to the drain circuit (3a) so as to return directly to the oil tank (4) without going through the oil tank (4), and the directional switching valve (6g) and the work implement (10) Of the two oil supply circuits to be connected, when the breaker (10a) is attached, it is provided in the other side circuit (12) that supplies pressure oil to the breaker (10a), and the set pressure is switched between high and low A pressure-variable safety valve (30) that can be provided, and the three-way switching valve (3
A hydraulic circuit for a working machine, comprising: a mode switching means (40) capable of switching between 4) and a variable pressure safety valve (30) in an interlocked manner.
複数個のパイロット油圧作動式の方向切換弁(6a〜6g)の
ストロークを、パイロット圧力比例制御弁(20)からのパ
イロット圧力により制御し、圧油の流量を調整するパイ
ロット圧力比例制御式油圧装置を有し、フロントリンク
機構には、前記方向切換弁(6g)から供給される圧油によ
り作動する、少なくともブレーカ(10a)を含む複数の作
業機(10)を、交換自在に取り付け可能とした油圧ショベ
ルの作業機用の油圧回路において、前記方向切換弁(6g)
と作業機(10)とを接続する２本の送油回路のうちの、一
側回路(11)上に設けられ、ブレーカ(10a)を取り付けた
ときに、ブレーカ(10a)からの戻り油を前記方向切換弁
(6g)を介さずに直接オイルタンク(4)に戻すように、接
続をドレン回路(3a)に切り換える３方向切換弁(34)と、
前記方向切換弁(6g)の流量調整をするために、パイロッ
ト圧力比例制御弁(20)のパイロット元圧力を制御する電
磁比例圧力制御弁(51)と、運転室内に設けられ、前記３
方向切換弁(34)を切り換えるモード切換手段(40)と、運
転室内に設けられ、前記電磁比例圧力制御弁(51)を制御
する流量調整手段(50)とを備えたことを特徴とする作業
機用の油圧回路。The strokes of a plurality of pilot hydraulically operated directional control valves (6a to 6g) for controlling the supply of pressure oil from a hydraulic pump are controlled by pilot pressure from a pilot pressure proportional control valve (20). The front link mechanism has a pilot pressure proportional control type hydraulic device that adjusts the flow rate of the pressure oil, and the front link mechanism includes at least a breaker (10a) that is operated by the pressure oil supplied from the direction switching valve (6g). A plurality of working machines (10), in a hydraulic circuit for working machines of a hydraulic shovel capable of being interchangeably mounted, the directional control valve (6g)
When the breaker (10a) is installed, the return oil from the breaker (10a) is provided on one side circuit (11) of the two oil feed circuits that connect the work machine (10) with the work machine (10). Directional valve
(6g) a three-way switching valve (34) for switching the connection to the drain circuit (3a) so as to return directly to the oil tank (4) without going through
An electromagnetic proportional pressure control valve (51) for controlling a pilot source pressure of a pilot pressure proportional control valve (20) for adjusting a flow rate of the direction switching valve (6g);
Work characterized by comprising: mode switching means (40) for switching the direction switching valve (34); and flow rate adjusting means (50) provided in the cab and controlling the electromagnetic proportional pressure control valve (51). Hydraulic circuit for the machine.
いて、前記方向切換弁(6g)と作業機(10)とを接続する２
本の送油回路のうちの、ブレーカ(10a)が取り付けられ
たときにブレーカ(10a)に圧油を供給する他側回路(12)
に設けられ、設定圧力を高低２段に切換可能な圧力可変
式安全弁(30)と、運転室内に設けられ、前記３方向切換
弁(34)と前記圧力可変式安全弁(30)とを連動して切換可
能なモード切換手段(40)とを備えたことを特徴とする作
業機用の油圧回路。3. The hydraulic circuit for a working machine according to claim 2, wherein the directional control valve (6g) is connected to the working machine (10).
The other side circuit (12) of the oil supply circuit that supplies pressure oil to the breaker (10a) when the breaker (10a) is installed
, A pressure-variable safety valve (30) capable of switching a set pressure between high and low stages, and a three-way switching valve (34) provided in the cab and interlocking the variable-pressure safety valve (30). A hydraulic circuit for a working machine, comprising: a mode switching means (40) that can be switched by switching.
Priority Applications (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP2001095316A JP2002294758A (en) | 2001-03-29 | 2001-03-29 | Hydraulic circuit for working machine |
| KR1020020015097A KR20020077067A (en) | 2001-03-29 | 2002-03-20 | Hydraulic circuit for work machine |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP2001095316A JP2002294758A (en) | 2001-03-29 | 2001-03-29 | Hydraulic circuit for working machine |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| JP2002294758A true JP2002294758A (en) | 2002-10-09 |
Family
ID=18949384
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP2001095316A Pending JP2002294758A (en) | 2001-03-29 | 2001-03-29 | Hydraulic circuit for working machine |
Country Status (2)
| Country | Link |
|---|---|
| JP (1) | JP2002294758A (en) |
| KR (1) | KR20020077067A (en) |
Cited By (8)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| EP1925825A2 (en) | 2006-11-27 | 2008-05-28 | Kobelco Construction Machinery Co., Ltd. | Relief pressure switching apparatus for hydraulic working machine |
| US7478530B2 (en) | 2005-06-22 | 2009-01-20 | Kobelco Construction Machinery Co., Ltd. | Hydraulic circuit for working machine |
| WO2010116816A1 (en) * | 2009-04-06 | 2010-10-14 | 日立建機株式会社 | Hydraulic circuit apparatus for hydraulic shovel |
| KR101389581B1 (en) * | 2007-07-13 | 2014-04-29 | 두산인프라코어 주식회사 | Control apparatus for option attatchment of excavator |
| CN104074816A (en) * | 2014-06-23 | 2014-10-01 | 湖南三一路面机械有限公司 | Milling machine tail door control system and milling machine |
| CN104674866A (en) * | 2015-01-30 | 2015-06-03 | 福建农林大学 | Vibration excavator adjustable in amplitude and frequency |
| JP2018135704A (en) * | 2017-02-22 | 2018-08-30 | 日立建機株式会社 | Hydraulic Excavator |
| CN109570426A (en) * | 2019-01-22 | 2019-04-05 | 青岛海德马克智能装备有限公司 | A kind of clamping control system and radial forging operate machine |
-
2001
- 2001-03-29 JP JP2001095316A patent/JP2002294758A/en active Pending
-
2002
- 2002-03-20 KR KR1020020015097A patent/KR20020077067A/en not_active Application Discontinuation
Cited By (15)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| EP1736672A3 (en) * | 2005-06-22 | 2011-11-09 | Kobelco Construction Machinery Co., Ltd. | Hydraulic circuit for working machine |
| US7478530B2 (en) | 2005-06-22 | 2009-01-20 | Kobelco Construction Machinery Co., Ltd. | Hydraulic circuit for working machine |
| CN1884849B (en) * | 2005-06-22 | 2010-08-04 | 神钢建设机械株式会社 | Hydraulic circuit for working machine |
| US7810321B2 (en) | 2006-11-27 | 2010-10-12 | Kobelco Construction Machinery Co., Ltd. | Relief pressure switching apparatus for hydraulic working machine |
| EP1925825A2 (en) | 2006-11-27 | 2008-05-28 | Kobelco Construction Machinery Co., Ltd. | Relief pressure switching apparatus for hydraulic working machine |
| KR101389581B1 (en) * | 2007-07-13 | 2014-04-29 | 두산인프라코어 주식회사 | Control apparatus for option attatchment of excavator |
| CN102066670A (en) * | 2009-04-06 | 2011-05-18 | 日立建机株式会社 | Hydraulic circuit apparatus for hydraulic shovel |
| JP2010242375A (en) * | 2009-04-06 | 2010-10-28 | Hitachi Constr Mach Co Ltd | Hydraulic circuit device for hydraulic shovel |
| US8387289B2 (en) | 2009-04-06 | 2013-03-05 | Hitachi Construction Machinery Co., Ltd. | Hydraulic circuit system for hydraulic excavator |
| WO2010116816A1 (en) * | 2009-04-06 | 2010-10-14 | 日立建機株式会社 | Hydraulic circuit apparatus for hydraulic shovel |
| CN104074816A (en) * | 2014-06-23 | 2014-10-01 | 湖南三一路面机械有限公司 | Milling machine tail door control system and milling machine |
| CN104074816B (en) * | 2014-06-23 | 2016-05-25 | 湖南三一路面机械有限公司 | A kind of milling machine Control system of gate and milling machine |
| CN104674866A (en) * | 2015-01-30 | 2015-06-03 | 福建农林大学 | Vibration excavator adjustable in amplitude and frequency |
| JP2018135704A (en) * | 2017-02-22 | 2018-08-30 | 日立建機株式会社 | Hydraulic Excavator |
| CN109570426A (en) * | 2019-01-22 | 2019-04-05 | 青岛海德马克智能装备有限公司 | A kind of clamping control system and radial forging operate machine |
Also Published As
| Publication number | Publication date |
|---|---|
| KR20020077067A (en) | 2002-10-11 |
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