JPH02261903A - Hydraulic circuit in closed center load sensing system - Google Patents

Hydraulic circuit in closed center load sensing system

Info

Publication number
JPH02261903A
JPH02261903A JP8296289A JP8296289A JPH02261903A JP H02261903 A JPH02261903 A JP H02261903A JP 8296289 A JP8296289 A JP 8296289A JP 8296289 A JP8296289 A JP 8296289A JP H02261903 A JPH02261903 A JP H02261903A
Authority
JP
Japan
Prior art keywords
change
switching valve
closed center
pump
over
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
Application number
JP8296289A
Other languages
Japanese (ja)
Inventor
Hiroshi Imai
寛 今井
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Komatsu Ltd
Original Assignee
Komatsu Ltd
Priority date (The priority date 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 date listed.)
Filing date
Publication date
Application filed by Komatsu Ltd filed Critical Komatsu Ltd
Priority to JP8296289A priority Critical patent/JPH02261903A/en
Priority to PCT/JP1990/000414 priority patent/WO1990012212A1/en
Publication of JPH02261903A publication Critical patent/JPH02261903A/en
Pending legal-status Critical Current

Links

Classifications

    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F15—FLUID-PRESSURE ACTUATORS; HYDRAULICS OR PNEUMATICS IN GENERAL
    • F15B—SYSTEMS ACTING BY MEANS OF FLUIDS IN GENERAL; FLUID-PRESSURE ACTUATORS, e.g. SERVOMOTORS; DETAILS OF FLUID-PRESSURE SYSTEMS, NOT OTHERWISE PROVIDED FOR
    • F15B13/00—Details of servomotor systems ; Valves for servomotor systems
    • F15B13/02—Fluid distribution or supply devices characterised by their adaptation to the control of servomotors
    • F15B13/04—Fluid distribution or supply devices characterised by their adaptation to the control of servomotors for use with a single servomotor
    • F15B13/042—Fluid distribution or supply devices characterised by their adaptation to the control of servomotors for use with a single servomotor operated by fluid pressure
    • F15B13/0422—Fluid distribution or supply devices characterised by their adaptation to the control of servomotors for use with a single servomotor operated by fluid pressure with manually-operated pilot valves, e.g. joysticks

Landscapes

  • Engineering & Computer Science (AREA)
  • Physics & Mathematics (AREA)
  • Fluid Mechanics (AREA)
  • Mechanical Engineering (AREA)
  • General Engineering & Computer Science (AREA)
  • Operation Control Of Excavators (AREA)
  • Fluid-Pressure Circuits (AREA)

Abstract

PURPOSE:To improve responsiveness and staticity by connecting a change-over valve which changes over interlocking to an operating lever of a change-over valve of a closed center to a piping between a pump and the change-over valve of the closed center. CONSTITUTION:When an operating lever is operated for starting a driving or an operating machine, hydraulic pressure from pilot proportional pressure valves 20a and 21a flows in a two port change-over valve 25 through shuttle valves 20b, 21b and 22 and changes them over, and simultaneously flows in stack type change-over valves 5, 6 of an operated closed center and changes them over. At this time, as the change of an opening area of the two port change-over valve 25 smoothly changes in proportion to the pressure of the stack type pilot proportional pressure valves 20a, 21a, the discharge amount of the pump 2 flowing in a tank 9 gradually decreases and the flow amount to actuators 3, 4 gradually increases. Additionally, as there is no restrictor between the two port change-over valve 25 and the change-over valves 5, 6, the transmission of pressure improves. Consequently, it is possible to improve responsibility and staticity.

Description

【発明の詳細な説明】 （産業上の利用分野） 本発明は、クローズドセンタ・ロードセンシングシステ
ムにおける油圧回路に係わり、特には、パワーシーベル
等の建設機械に用い、応答性、静定性の良い操作を得る
クローズドセンタ・ロードセンシングシステムにおける
油圧回路の改良に関する。Detailed Description of the Invention (Industrial Field of Application) The present invention relates to a hydraulic circuit in a closed center load sensing system, and is particularly applicable to construction machinery such as a power siebel, and is used to improve responsiveness and static stability in operation. This invention relates to improvements in hydraulic circuits in closed-center load sensing systems.

（従来の技術） ｔｉ来、ｍ設機械のパワーシ碧ベル等にはエンジンｌに
駆動される油圧源用のポンプ２と慣性負荷の小さいパケ
ットあるいは慣性負荷の大きい車体の走行等を駆動する
バケットのアクチエエータ３あるいは走行装置のアクチ
ュエータ４への油圧を切り換える切換弁５．６とを配管
７で連結した第５図の回路のものが主に用いられている
。最近では、この場合切換弁５．６にはクローズドセン
タ方式が使用されるとともにポンプ２はポンプの吐出容
積を負荷圧によりポンプの吐出量を可変にするロードセ
ンシングシステムが用いられている。切換弁５．６の切
り換えには図示しない運転席の近傍に配設された操作レ
バー２０．２１の操作により作動するパイロット比例圧
力弁２０ａ、２１ａからの油圧指令により行っている。(Prior Art) Since then, power shovels and the like of m-equipment machines have been equipped with a pump 2 for a hydraulic source driven by an engine 1 and a bucket for driving a packet with a small inertial load or a vehicle body with a large inertial load. The circuit shown in FIG. 5 is mainly used, in which the actuator 3 or a switching valve 5.6 for switching the hydraulic pressure to the actuator 4 of the traveling device is connected by a pipe 7. Recently, in this case, a closed center system is used for the switching valve 5.6, and a load sensing system is used for the pump 2, which changes the discharge volume of the pump depending on the load pressure. The switching of the switching valve 5.6 is performed by hydraulic pressure commands from pilot proportional pressure valves 20a and 21a which are activated by operating a control lever 20.21 disposed near the driver's seat (not shown).

（発明が解決しようとする課ｎ） しかしながら、上記従来のロードセンシングシステムで
は、慣性負荷の大きい走行を作動させるときには絞り４
０の大きさが大きい第６図の（イ）のごとくアクチエエ
ータのスピードが安定するまでの静定性（第６図の記号
Ｅ）が悪く、絞り４０の大きさが小さいと（ロ）のごと
く車体が動きだすまでにタイムラグがあり応答性（第６
図の記号Ｆ）が悪いと言う欠点があるこのために、切換
弁とバイロフト比例圧力弁との間に絞り４０を設けて両
者のバランスを得ているが、特に操作レバーを急操作し
たときに応答性、静定性の両者を満足するクローズドセ
ンタ・ロードセンシングシステムの油圧口ＩＩヲ得るこ
とは困難であるという欠点がある。(Issue n to be solved by the invention) However, in the above-mentioned conventional load sensing system, when operating traveling with a large inertial load, the aperture 4
If the size of the aperture 40 is large, as shown in (a) in Figure 6, the static stability (symbol E in Figure 6) until the actuator speed becomes stable is poor, and if the size of the aperture 40 is small, the vehicle body will deteriorate as shown in (b). There is a time lag before the machine starts to move, and the responsiveness (6th
For this reason, a throttle 40 is provided between the switching valve and the biloft proportional pressure valve to maintain a balance between the two, but especially when the operating lever is suddenly operated, There is a drawback in that it is difficult to obtain a hydraulic port II for a closed center load sensing system that satisfies both responsiveness and static stability.

本発明は上記従来のＩｕ！！１点に着目し、応答性、静
定性の良いクローズドセンタ・ロードセンシングシステ
ムにおける油圧回路の提供を目的とする。The present invention is based on the conventional Iu! ! Focusing on one point, we aim to provide a hydraulic circuit for a closed center load sensing system with good responsiveness and static stability.

（課題を解決するための手段） 上記目的を達成するために、本発明に係わる第１の発明
では、少なくとも１（２）以上のクローズドセンタの切
換弁とポンプの吐出容積を負荷圧により可変とするロー
ドセンシングシステムを搭載する建設機械において、ポ
ンプとクローズドセンタの切換弁との間の配管に接続し
、かつクローズドセンタの切換弁の操作レバーに連動し
て切り換わるす換弁を設けている。第２の発明では、切
換弁は少なくとも２ポ一ト２位置をし、切換時にポンプ
からタンクへの回路を遮断する構成としている。(Means for Solving the Problems) In order to achieve the above object, in the first aspect of the present invention, the discharge volume of at least one (2) or more closed center switching valves and pumps is made variable depending on the load pressure. A construction machine equipped with a load sensing system is provided with a switching valve that is connected to piping between the pump and the closed center switching valve and that switches in conjunction with the operating lever of the closed center switching valve. In the second invention, the switching valve has at least two points and two positions, and is configured to cut off the circuit from the pump to the tank when switching.

（作　用） 上記構成によれば、クローズドセンタ・ロードセンシン
グシステムにおいて、ポンプから２ポート切換弁を経由
してタンクに流れていた油量が２ポート切換弁によりタ
ンクへの回路が滑らかに遮断されるので、２ポート切換
弁で滑らかに遮断しているため静定性が良くなり、静定
性を高める絞りが不必要となり応答性を高めることがで
きる。これにより慣性負荷の大きい車体の走行等を駆動
するときでも、１１１１１作によりパイロット比例圧力
弁と切換弁との間の油圧の伝達が速くなりタイムラグを
小さくできる。(Function) According to the above configuration, in the closed center load sensing system, the amount of oil that was flowing from the pump to the tank via the 2-port switching valve is smoothly cut off from the circuit to the tank by the 2-port switching valve. Since the 2-port switching valve smoothly shuts off the valve, static stability is improved, and a throttle that increases static stability is not required, which improves responsiveness. As a result, even when driving a vehicle body with a large inertial load, the transmission of hydraulic pressure between the pilot proportional pressure valve and the switching valve becomes faster and the time lag can be reduced.

（実施例） 以下に、本発明に係わるクローズドセンタ・ロードセン
シングシステムにおける油圧回路の実施例につき、図面
を参照して詳細に説明する。第１図は第１実施例を示し
、エンジン等の動力源１に駆動される可変容量形ポンプ
２（以下、ポンプ２と言う。）と、図示しない作業機を
作動するブーム、アーム、パケット用の内のバケットの
アクチエエータ３と、車両を走行する走行装置用のアク
チエエータ４に油圧を給排するクローズドセンタのスタ
ック形の切換弁５．６が１個に結合され、配管７で可変
容量形ポンプ２に、配管８でタンク９に連結されている
。(Example) Hereinafter, an example of a hydraulic circuit in a closed center load sensing system according to the present invention will be described in detail with reference to the drawings. FIG. 1 shows a first embodiment, which includes a variable displacement pump 2 (hereinafter referred to as pump 2) driven by a power source 1 such as an engine, and a boom, arm, and packet pump that operate a working machine (not shown). A closed center stack-type switching valve 5.6 for supplying and discharging hydraulic pressure to the actuator 3 of the bucket and the actuator 4 for the traveling device that runs the vehicle are combined into one, and a variable displacement pump is connected via piping 7. 2, it is connected to a tank 9 by a pipe 8.

ポンプ２にはポンプの吐出容積を可変にする通常のレギ
ユレータ１０がレギエレータパルブ１１　（以下、バル
ブ１１と言う。）と、ポンプ２の配管７より分岐したパ
イロット配管１２とを経由して配管７に接続され、ポン
プ２の吐出圧Ｐｐを受はポンプ２の吐出容積Ｑｐを１１
御している。切換弁５．６にはポンプ２からの配管７に
並列に配管７ａ、７ｂが連結されるとともに、パケット
のアクチエエータ３には配管３ａ−＝３ｂが、また走行
装置のアクチエエータ４には配管４ａｓ４ｂが連結され
ている。切換弁５．６は３位置よりなり、中立位置Ｎで
はポンプボートはクローズドされており、切換位ｉ１Ｌ
、　Ｍまでにはスプール等に設けられたスロットリング
の可変の絞り１３で絞られ、またφ換位置し、Ｍでは絞
り１３は一定の面積になっているとともに各位置でポー
トＲを経てシャトル弁１４に連結されている。シャトル
弁１４、Ｉｓはパイロット管１６ａ、１６ｂで連結され
るとともに、パイロット管１７を介して各アクチュエ−
タ３．４の配管３ａ、３ｂ、４ａ、４ｂへの回路に挿入
された減圧弁１８ａ、１８ｂ、１９ａ１９ｂに導かれて
いる。また、切換弁５．６は図示しない運転席の近傍に
設けられた操作レバー２０．２１の操作によるパイロッ
ト比例圧力弁２０ａ、２１ａからの圧力指令を受けて切
り換わる。パイロット比例圧力弁２０ａ、２１ａからの
油圧は、またシャトル弁２０ｂ、２１ｂとシャトル弁２
２を介して、ポンプ２の吐出口とクローズドセンタの切
換弁５．６との間の配管７に連結された２ポ一ト２位置
を有する切換弁２５（以下、２ボート切換弁２５と言う
。A normal regulator 10 that makes the discharge volume of the pump variable is connected to the pump 2 via a regulator valve 11 (hereinafter referred to as valve 11) and a pilot pipe 12 branched from the pipe 7 of the pump 2. 7 and receives the discharge pressure Pp of the pump 2, the discharge volume Qp of the pump 2 is connected to 11
I am in control. Pipes 7a and 7b are connected in parallel to the piping 7 from the pump 2 to the switching valve 5.6, piping 3a-=3b is connected to the actuator 3 of the packet, and piping 4as4b is connected to the actuator 4 of the traveling device. connected. The switching valve 5.6 has three positions; in the neutral position N, the pump boat is closed, and in the switching position i1L.
, up to M, it is throttled by a variable throttle 13 of a throttle ring provided on the spool, etc., and is in the φ change position, and at M, the throttle 13 has a constant area, and at each position, it passes through port R to the shuttle valve. It is connected to 14. The shuttle valves 14 and Is are connected by pilot pipes 16a and 16b, and each actuator is connected via a pilot pipe 17.
The pressure reducing valves 18a, 18b, 19a19b are inserted into the circuits to the pipes 3a, 3b, 4a, 4b of the tank 3.4. Further, the switching valve 5.6 is switched in response to a pressure command from the pilot proportional pressure valves 20a, 21a by operating a control lever 20.21 provided near the driver's seat (not shown). The hydraulic pressure from the pilot proportional pressure valves 20a, 21a is also applied to shuttle valves 20b, 21b and shuttle valve 2.
A switching valve 25 (hereinafter referred to as the two-boat switching valve 25) having two points and two positions is connected to the pipe 7 between the discharge port of the pump 2 and the closed center switching valve 5.6 via the .

）に連結されている。２ボート切換弁は通常はＳボート
では開でありタンク９に連結され、切り換え時にはＴポ
ートの閉となっている。この例では、パイロット比例圧
力弁を用いて油圧を使用したが電気あるいは空気による
指令でも良い。) is connected to. The two-boat switching valve is normally open in the S boat and connected to the tank 9, and the T port is closed during switching. In this example, hydraulic pressure was used using a pilot proportional pressure valve, but electrical or pneumatic commands may also be used.

上記実施例において、次に作動について説明する。車両
の走行あるいは作業機を作動させるため操作レバーを操
作するとパイロット比例圧力弁２０ａ、２１ａからの油
圧はシャトル弁２０ｂ、２１ｂとシャトル弁２２を介し
て２ボート切換弁２５に流入し切り換えるとともに、操
作された切換弁５．６に流入し切り換える。このとき、
２ボート切換弁２５の回路の遮断の変化（関口面積の変
化）は第２図のごとくパイロット比例圧力弁２０ａ、２
ｔａの圧力に比例して滑らかに変化するためにポンプ２
の吐出量がタンク９へ流れていたのが徐々に少な（なり
アクチュエータ３．４への流入量が徐々に静定性が良く
増加する。さらに２ボート切換弁２５と切換弁５．６と
の間に絞りがないためパイロット比例圧力弁２０ａ、２
１ａから２ボート切換弁２５への圧力の伝達がよくなり
応答性がよくタイムラグが少なくなる。Next, the operation of the above embodiment will be explained. When the operating lever is operated to drive the vehicle or operate the work equipment, the hydraulic pressure from the pilot proportional pressure valves 20a and 21a flows into the two-boat switching valve 25 via the shuttle valves 20b and 21b and the shuttle valve 22, and is switched and operated. It flows into the selected switching valve 5.6 and switches. At this time,
The change in circuit cutoff (change in Sekiguchi area) of the two-boat switching valve 25 is determined by the pilot proportional pressure valves 20a and 2 as shown in Figure 2.
Pump 2 to change smoothly in proportion to the pressure of ta.
The discharge amount flowing into the tank 9 gradually decreases (the amount flowing into the actuator 3.4 gradually increases with good static stability. Furthermore, between the two-boat switching valve 25 and the switching valve 5.6 Since there is no restriction in the pilot proportional pressure valves 20a, 2
The pressure is better transmitted from 1a to the two-boat switching valve 25, resulting in better responsiveness and less time lag.

第３図は第２実施例の全体構成図を示し、第１実施例と
同一部品には同一符号を付し説明を省略する。ポンプ２
の吐出容積を可変にする通常のレギユレータ１０への油
圧はチエツク弁１４．１５からのパイロット管１６ｂに
絞り３０を設けている。FIG. 3 shows an overall configuration diagram of the second embodiment, and the same parts as in the first embodiment are denoted by the same reference numerals, and the explanation thereof will be omitted. pump 2
A restrictor 30 is provided in the pilot pipe 16b from the check valve 14, 15 to supply hydraulic pressure to the normal regulator 10 that changes the discharge volume of the check valve 14, 15.

上記構成において、次に作動について説明する。第１実
施例と同様に、車両の走行あるいは作業機を作動させる
ため操作レバーを操作するとパイロット比例圧力弁２０
ａ、２１ａからの油圧はシャトル弁２０ｂ、２１ｂとシ
ャトル弁２２を介して２ボート切換弁２５に流入し切り
換えるとともに、操作された切換弁５．６に流入し切り
換える。このとき、２ボート切換弁２５の回路の遮断の
変化（開口面積の変化）は第１実施例と同様に第２図の
ごとくパイロット比例圧力弁２０ａ、２１ａの圧力に比
例して滑らかに変化するがポンプ２の吐出量は絞り３０
により作動が少し遅れるとともにポンプ２の吐出量が第
４図の（ハ）のごとく漸次流量を増していく。これによ
りポンプ２の吐出量がタンク９へ流れていたのが徐々に
少なくなるとともにアクチュエータ３．４への流入量が
徐々に増加するため静定性が良くなる。さらに第１実施
例と同様に２ボート切換弁２５と切換弁５．６との間に
絞りがないためパイロット比例圧力弁２０ａ、２１ａか
ら２ボート切換弁２５への圧力の伝達がよくなり応答性
がよくタイムラグが少なくなる。In the above configuration, the operation will be explained next. As in the first embodiment, when the operating lever is operated to drive the vehicle or operate the work equipment, the pilot proportional pressure valve 20
The hydraulic pressure from a and 21a flows into the two-boat switching valve 25 through the shuttle valves 20b and 21b and the shuttle valve 22 to switch the valve, and also flows into the operated switching valve 5.6 to switch the valve. At this time, the change in the circuit interruption (change in opening area) of the two-boat switching valve 25 changes smoothly in proportion to the pressure in the pilot proportional pressure valves 20a and 21a, as shown in FIG. 2, as in the first embodiment. However, the discharge amount of pump 2 is 30
As a result, the operation is slightly delayed and the discharge amount of the pump 2 gradually increases as shown in FIG. 4(c). As a result, the amount of discharge from the pump 2 that was flowing into the tank 9 gradually decreases, and the amount that flows into the actuator 3.4 gradually increases, improving static stability. Furthermore, as in the first embodiment, since there is no restriction between the two-boat switching valve 25 and the switching valve 5.6, the pressure is better transmitted from the pilot proportional pressure valves 20a and 21a to the two-boat switching valve 25, resulting in improved responsiveness. is better and the time lag is reduced.

なお、上記実施例においてポンプからタンクへの流量の
変化およびポンプの吐出量の変化を１次比例して変化さ
せているが２次、３次および他の連続した変動でも良い
。In the above embodiment, the change in flow rate from the pump to the tank and the change in the discharge amount of the pump are changed in linear proportion, but they may be changed in second order, third order, or other continuous variations.

（発明の効果） 以上説明したように本発明によれば、クローズドセンタ
・ロードセンシングシステムにおける油圧回路のポンプ
から２ボート切換弁を経由してタンクに流れていた油量
をタンクへの回路の滑らかな遮断により慣性負荷の小さ
いパケットを作動させるときでも静定性を良く切り換え
ることができる。また、切換弁とパイロット比例圧力弁
との間に絞りを設ける必要がなくなるので応答性を高め
ることができるとともに、２ボート切換弁で滑らかに遮
断しているため静定性が良くなる（第６図の（ニ））、
これにより慣性負荷の大きい車体の走行等を駆動するの
に急操作が可能となりタイムラグを小さくできると言う
優れた妨果が得られる。(Effects of the Invention) As explained above, according to the present invention, the amount of oil flowing from the pump of the hydraulic circuit in the closed center load sensing system to the tank via the two-boat switching valve can be changed smoothly through the circuit to the tank. The static stability can be switched well even when operating a packet with a small inertial load by shutting it down. In addition, since there is no need to provide a restriction between the switching valve and the pilot proportional pressure valve, responsiveness can be improved, and the static stability is improved because the two-boat switching valve smoothly shuts off the valve (see Figure 6). (d)),
This provides an excellent effect in that sudden operations can be made to drive the running of a vehicle body with a large inertial load, and the time lag can be reduced.

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

１１図は本発明はクローズドセンタ・ロードセンシング
システムにおける油圧回路の第１実施例を示す全体構成
図。 第２図は本発明のパイロット比例圧力弁の圧力と２ポー
ト切換弁の開口面積の変化の関係の一例を示す図。 第３図は本発明はクローズドセンタ・ロードセンシング
システムにおける油圧回路の第２実施例を示す全体構成
図。 第４図（ａ）は本発明のパイロット比例圧力弁の圧力と
２ポート切換弁の開口面積の変化、第４図（ｂ）パイロ
ット比例圧力弁の圧力とポンプの吐出量の変化の関係の
一例を示す図。 ｆｆ１５１ｍは従来のクローズドセンタ・ロードセンシ
ングシステムにおける油圧回路の実施例を示す全体構成
図。 第６回は本案と従来のアクチエエータへの流量を説明す
るタイムチャート図。 １・・・・・・−動力源、 ２−・−・・・可変容量形ポンプ ３　・・・−・アクチエエータ（プーム）４・・・・・
・アクチエエータ（走行）５．６　・−・・・切換弁 ＩＯ・・・・・　レギユレータ １１−・・・−レギエレータバルプ １４．１５．２０ｂ、２１ｂ、２２　　・・・・・シャ
トル弁 １８ａ、　１８　ｂ、　１９ａＳ１９　ｂ　−減圧弁 ２５・・・・・・　２ポート切換弁 ３０・・・−・−絞りFIG. 11 is an overall configuration diagram showing a first embodiment of a hydraulic circuit in a closed center load sensing system according to the present invention. FIG. 2 is a diagram showing an example of the relationship between the pressure of the pilot proportional pressure valve of the present invention and the change in the opening area of the 2-port switching valve. FIG. 3 is an overall configuration diagram showing a second embodiment of a hydraulic circuit in a closed center load sensing system according to the present invention. FIG. 4(a) shows an example of the relationship between the pressure of the pilot proportional pressure valve and the opening area of the 2-port switching valve of the present invention, and FIG. 4(b) shows an example of the relationship between the pressure of the pilot proportional pressure valve and the change in pump discharge amount. Diagram showing. ff151m is an overall configuration diagram showing an example of a hydraulic circuit in a conventional closed center load sensing system. The 6th time chart is a time chart explaining the flow rate to the actuator of the present invention and the conventional actuator. 1...--power source, 2---variable displacement pump 3...--actuator (poom) 4...
- Actuator (traveling) 5.6 ... Switching valve IO ... Regulator 11 - ... Regulator valve 14.15.20b, 21b, 22 ... Shuttle valve 18a, 18 b, 19aS19 b - Pressure reducing valve 25... 2 port switching valve 30... - Throttle

Claims (2)

【特許請求の範囲】[Claims] （１）　少なくとも１個以上のクローズドセンタの切換
弁とポンプの吐出容積を負荷圧により可変とするロード
センシングシステムを搭載する建設機械において、ポン
プとクローズドセンタの切換弁との間の配管に接続し、
かつクローズドセンタの切換弁の操作レバーに連動して
切り換わる切換弁を設けたことを特徴とするクローズド
センタ・ロードセンシングシステムにおける油圧回路。(1) In a construction machine equipped with at least one closed center switching valve and a load sensing system that changes the pump discharge volume depending on the load pressure, connect the pipe between the pump and the closed center switching valve. ,
A hydraulic circuit in a closed center load sensing system, further comprising a switching valve that switches in conjunction with an operating lever of the closed center switching valve. （２）　切換弁は少なくとも２ポート２位置を有し、切
換時にポンプからタンクへの回路を遮断する請求項１記
載のクローズドセンタ・ロードセンシングシステムにお
ける油圧回路。(2) The hydraulic circuit in the closed center load sensing system according to claim 1, wherein the switching valve has at least two ports and two positions, and interrupts the circuit from the pump to the tank when switching.
JP8296289A 1989-03-31 1989-03-31 Hydraulic circuit in closed center load sensing system Pending JPH02261903A (en)

Priority Applications (2)

Application Number Priority Date Filing Date Title
JP8296289A JPH02261903A (en) 1989-03-31 1989-03-31 Hydraulic circuit in closed center load sensing system
PCT/JP1990/000414 WO1990012212A1 (en) 1989-03-31 1990-03-28 Hydraulic circuit of closed center load sensing system

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
JP8296289A JPH02261903A (en) 1989-03-31 1989-03-31 Hydraulic circuit in closed center load sensing system

Publications (1)

Publication Number Publication Date
JPH02261903A true JPH02261903A (en) 1990-10-24

Family

ID=13788849

Family Applications (1)

Application Number Title Priority Date Filing Date
JP8296289A Pending JPH02261903A (en) 1989-03-31 1989-03-31 Hydraulic circuit in closed center load sensing system

Country Status (2)

Country Link
JP (1) JPH02261903A (en)
WO (1) WO1990012212A1 (en)

Families Citing this family (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO1991002903A1 (en) * 1989-08-16 1991-03-07 Kabushiki Kaisha Komatsu Seisakusho Hydraulic circuit device
WO2014148808A1 (en) * 2013-03-19 2014-09-25 두산인프라코어 주식회사 Construction equipment hydraulic system and control method therefor

Family Cites Families (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS5843537B2 (en) * 1974-12-30 1983-09-27 日立建機 （株） Hydraulic excavator hydraulic control device

Also Published As

Publication number Publication date
WO1990012212A1 (en) 1990-10-18

Similar Documents

Publication Publication Date Title
US8146355B2 (en) Traveling device for crawler type heavy equipment
EP2107170B1 (en) Hydraulic drive system for a civil engineering or construction machine.
JPH11218102A (en) Pressurized oil supply device
US6176126B1 (en) Engine speed control system for construction machine
EP1970571B1 (en) Hydraulic circuit for construction machine
JP2002181008A (en) Hydraulic controller
JP2004027706A (en) Hydraulic circuit device for construction machinery
JPH06306892A (en) Travel controlling of construction machinery
JPH08105078A (en) Variable priority device
JPH02261903A (en) Hydraulic circuit in closed center load sensing system
JP2799045B2 (en) Hydraulic circuit for crane
JP3139792B2 (en) Straight running circuit for construction vehicles
JPH11336135A (en) Hydraulic control circuit for construction machine
JP2005068845A (en) Hydraulic circuit of construction machine
JPH0470429A (en) Hydraulic circuit for construction machine
JP3662623B2 (en) Load sensing circuit
JP5036486B2 (en) Hydraulic circuit and hydraulic control device for construction machinery
JPH05106606A (en) Hydrauliccircuit for construction machine
JPS60250132A (en) Oil pressure control circuit for construction vehicle
JP2765605B2 (en) Hydraulic working machine hydraulic circuit
JP3218299B2 (en) Travel speed control circuit for construction machinery
KR100480975B1 (en) An apparatus for controlling by-pass flow rate of a heavy equipment
JPH0893706A (en) Hydraulic driving circuit
JPS6322930A (en) Hydraulic circuit for construction machine
JPH0674054B2 (en) Straight traveling control circuit device for hydraulic traveling vehicle