JPH01275902A - Discharge rate control circuit for load pressure compensating pump - Google Patents
Discharge rate control circuit for load pressure compensating pumpInfo
- Publication number
- JPH01275902A JPH01275902A JP10494488A JP10494488A JPH01275902A JP H01275902 A JPH01275902 A JP H01275902A JP 10494488 A JP10494488 A JP 10494488A JP 10494488 A JP10494488 A JP 10494488A JP H01275902 A JPH01275902 A JP H01275902A
- Authority
- JP
- Japan
- Prior art keywords
- flow rate
- switching valve
- pump
- discharge flow
- bypass
- 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.)
- Granted
Links
- 230000007935 neutral effect Effects 0.000 claims abstract description 13
- 230000007423 decrease Effects 0.000 claims description 5
- 238000011144 upstream manufacturing Methods 0.000 claims description 4
- 230000004043 responsiveness Effects 0.000 abstract description 3
- 230000003247 decreasing effect Effects 0.000 abstract description 2
- 239000012530 fluid Substances 0.000 abstract 1
- 238000010586 diagram Methods 0.000 description 8
- 230000004044 response Effects 0.000 description 6
- 230000000694 effects Effects 0.000 description 4
- 230000006835 compression Effects 0.000 description 2
- 238000007906 compression Methods 0.000 description 2
- 238000010276 construction Methods 0.000 description 2
- 239000010720 hydraulic oil Substances 0.000 description 2
- 239000003921 oil Substances 0.000 description 2
- 230000002159 abnormal effect Effects 0.000 description 1
- 238000001816 cooling Methods 0.000 description 1
- 238000007599 discharging Methods 0.000 description 1
- 230000001151 other effect Effects 0.000 description 1
- 238000003359 percent control normalization Methods 0.000 description 1
- 238000010792 warming Methods 0.000 description 1
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- Fluid-Pressure Circuits (AREA)
Abstract
Description
【発明の詳細な説明】
［産業上の利用分野］
建設機械用の油圧回路に係るもので、特にポンプ流量制
御される油圧回路において、切換弁にかかる負荷に関係
なくバイパス切換弁のストローク位置に応じて一定流量
を吐出し得るポンプ吐出流量制御回路に関するものであ
る。[Detailed Description of the Invention] [Industrial Application Field] This invention relates to a hydraulic circuit for construction machinery, and in particular, in a hydraulic circuit where pump flow rate is controlled, the stroke position of the bypass switching valve is adjusted regardless of the load applied to the switching valve. The present invention relates to a pump discharge flow rate control circuit that can discharge a constant flow rate according to the pump discharge flow rate.
［従来の技術］
建設機械用として過去に使用されたことのあるダイキン
パワーマー２チシステムについて説明する。第４図はそ
の回路図である。[Prior Art] The Daikin Power March 2March system, which has been used in the past for construction machinery, will be described. FIG. 4 is its circuit diagram.
本回路はバイパス通路なしのクローズドセンタになって
おり、切換弁の入口圧とシリンダボートの間に可変絞り
が設否されており、スプールストロークに応じて可変絞
りが変化し、その上・下流の圧力差によりポンプ吐出流
量を制御するようにしたものであり、シリンダ負荷に関
係なくスプールストローク位置に応じてポンプ流量を制
御できるものである。また、スプール中立時はポンプ吐
出流量がほぼＯになるように構成されている。This circuit is a closed center without a bypass passage, and a variable throttle is installed between the inlet pressure of the switching valve and the cylinder boat, and the variable throttle changes according to the spool stroke, and the upstream and downstream The pump discharge flow rate is controlled by the pressure difference, and the pump flow rate can be controlled according to the spool stroke position regardless of the cylinder load. Furthermore, the pump discharge flow rate is configured to be approximately O when the spool is neutral.
［発明が解決しようとする課題］
ところが、スプール中立時にポンプ吐出流量が０に近い
ために、流量を増大する応答がｄく、さらに、スプール
中立状態にメイクアップ効果の必要な慣性負荷の大きい
アクチュエータ（例えば旋回など）ではキャビテーショ
ンが発生し易い。[Problems to be Solved by the Invention] However, since the pump discharge flow rate is close to 0 when the spool is neutral, the response to increase the flow rate is slow, and furthermore, the actuator has a large inertial load that requires a make-up effect when the spool is neutral. (For example, when turning, etc.), cavitation is likely to occur.
また、入口圧力とシリンダボート圧力を検出しなければ
ならないので構造が複雑になり、コストアップの要因で
あり、特に多連弁になると最大負荷を検出するシャトル
バルブなどが必要となる。Furthermore, since the inlet pressure and cylinder boat pressure must be detected, the structure becomes complicated, which is a factor in increasing costs, and in particular, in the case of multiple valves, a shuttle valve or the like to detect the maximum load is required.
また、入口圧力とシリンダボート圧力との差圧によりポ
ンプ吐出流量を制御するために、シリンダボートに接続
された負荷によってシリンダボートにキャビテーション
が生じると、入口圧力とシリンダボート圧力との圧力差
が大きくなり、ポンプ吐出ｔ＆量を減じる方向にポンプ
が制御されるので、より一層ギヤビテーションを助長す
ることになるし、さらに、ポンプ吐出流量以上にシリン
ダボートからタンクボートに油を流出させると（面積差
も考慮に入れて）キャビテーションを助長することにな
るので、シリンダからタンクへの開［１面積と、供給路
からシリンダへの開口面積の設定に注意を要することに
なる。In addition, since the pump discharge flow rate is controlled by the differential pressure between the inlet pressure and the cylinder boat pressure, if cavitation occurs in the cylinder boat due to the load connected to the cylinder boat, the pressure difference between the inlet pressure and the cylinder boat pressure becomes large. As a result, the pump is controlled in the direction of reducing the pump discharge t & amount, which further promotes gearvitation.Furthermore, if oil flows out from the cylinder boat to the tank boat in excess of the pump discharge flow rate (area Since cavitation will be promoted (taking into consideration the difference between the two), care must be taken in setting the opening area from the cylinder to the tank and the opening area from the supply path to the cylinder.
また、スプールを中立へ急激に戻す操作において、ポン
プの応答性が遅い場合はサージ圧が発生する。（メイン
リリーフバルブ付でもリリーフ圧までのサージ圧が発生
する。）
そこで、本発明は、スプール中立時にポンプ最小吐出流
量を通過できるバイパス通路を設け、アクチュエータの
応答性が良く、かつ種々の条件下でキャビテーションに
強く、構造の簡単な負荷圧補償をしたポンプ吐出流量制
御回路を提供することを目的とする。In addition, when the spool is suddenly returned to neutral, if the pump response is slow, a surge pressure is generated. (Surge pressure up to the relief pressure is generated even with a main relief valve.) Therefore, the present invention provides a bypass passage that can pass through the pump's minimum discharge flow rate when the spool is in the neutral state. The purpose of the present invention is to provide a pump discharge flow rate control circuit that is resistant to cavitation, has a simple structure, and has load pressure compensation.
［課題を解決するための手段］
パイロット信号により吐出流量を増減できるポンプと、
該ポンプに接続されたシリンダボートに油圧油を供給し
得る方向切換弁と、該方向切換弁の入口より分岐し一部
流量を流量制御弁を介してメータリング用バイパス切換
弁に通油させ、前記流量制御弁は前記バイパス切換弁の
上流側圧力と下流側圧力の差圧により制御され、また前
記切換弁中立時はポンプ吐出流量を最小とするように前
記パイロット信号を設定している構成から成り、前記パ
イロット信号を前記バイパス切換弁の最下流に設けた圧
力発生装置により取り出す構造としたネガティブ流量制
御を行なうこと、および前記切換弁が前記パイロット信
号により操作され前記パイロット信号の最大ポンプ吐出
信号を取り出してポンプ制御信号としたポジティブ流量
制御を行なうこと、とにより負荷圧に関係なくスプール
ストロークに応じたポンプ吐出流量制御を回部とする。[Means for solving the problem] A pump whose discharge flow rate can be increased or decreased by a pilot signal,
a directional switching valve capable of supplying hydraulic oil to a cylinder boat connected to the pump; branching from an inlet of the directional switching valve and allowing a portion of the flow rate to pass through a metering bypass switching valve via a flow rate control valve; The flow control valve is controlled by the differential pressure between the upstream pressure and the downstream pressure of the bypass switching valve, and the pilot signal is set so that the pump discharge flow rate is minimized when the switching valve is neutral. Negative flow control is performed in which the pilot signal is taken out by a pressure generator provided at the most downstream side of the bypass switching valve, and the switching valve is operated by the pilot signal to generate a maximum pump discharge signal of the pilot signal. By taking out the positive flow rate control and using it as a pump control signal, the pump discharge flow rate control is performed in accordance with the spool stroke regardless of the load pressure.
［作用］
切換弁中立時では、バイパス切換弁の開口面積が大であ
りパイロット信号圧力が高くなり、ポンプは最小吐出流
厳となる。[Function] When the switching valve is in neutral, the opening area of the bypass switching valve is large, the pilot signal pressure is high, and the pump has a strict minimum discharge flow.
また、バイパス通路でサージ圧を吸収し、かつ応答遅れ
を少なくする。In addition, the bypass passage absorbs surge pressure and reduces response delay.
切換弁ストローク途中では、ポンプ吐出流量の一部を流
量制御弁を介してバイパス切換弁に通油し、バイパス流
量はバイパス切換弁の開口面積に応じて一定流量となる
ように流量制御弁によって制御されるのでシリンダへの
流量は負荷圧に関係なくストローク位置に応じたパイロ
ット信号圧力によりポンプ吐出流量を一定流量になるよ
うに制御する。During the switching valve stroke, a portion of the pump discharge flow is passed through the flow control valve to the bypass switching valve, and the bypass flow rate is controlled by the flow control valve to maintain a constant flow rate according to the opening area of the bypass switching valve. Therefore, the flow rate to the cylinder is controlled so that the pump discharge flow rate is a constant flow rate by the pilot signal pressure according to the stroke position, regardless of the load pressure.
さらに、大きな負荷の場合バイパス流量を減じ、パイロ
ット信号圧力が下がりポンプ吐出流量を増大し、シリン
ダへの流量を充分なるようにポンプ吐出流量制御してキ
ャビテーションの発生を抑制する。Further, in the case of a large load, the bypass flow rate is reduced, the pilot signal pressure is lowered, and the pump discharge flow rate is increased, and the pump discharge flow rate is controlled so that the flow rate to the cylinder is sufficient, thereby suppressing the occurrence of cavitation.
［実施例］
第１図は本発明の一実施例であるネカティブ流量制御と
した場合の回路図であり、以Ｆこの図により説明する。[Embodiment] FIG. 1 is a circuit diagram in the case of negative flow rate control according to an embodiment of the present invention, and the following description will be made with reference to this diagram.
１０はパイロット信号により吐出流量を制御されるポン
プであり、そのポンプ１０かも吐出された油圧油は方向
切換弁１２の供給通路１３に接続され、一部流量はｆｌ
ｉｔ ％制御弁１４を介してバイパス切換弁１６に通油
された後、圧力発生装置１７を通過してタンク２３に排
出される。方向切換弁１２はその作動により負荷Ｗに接
続されたシリンダ１８の方向を制御し、また、流量制御
弁１４はバイパス切換弁１６の上瀉側圧力と下流側圧力
の差圧により制御され、バイパス切換弁１６のバイパス
開口面積が大Ｓい場合（差圧が小）圧縮バネ１９に抗し
て閉じてくる構造となっており、供給通路１３の圧力に
関係なくバイパス開口面積に見合った流量を通過し得る
。バイパス切換弁１６は中立時最大開口となり、スプー
ルストロークエンドではその通路を閉め切り、ストロー
ク途中では流７．１制御弁１４との関係から最適な開口
面積を有している。また、方向切換弁１２と７＜、イパ
ヌ切換弁１６は連結しており、以後これらを総称１．て
ｊ、ＩＪ換弁と呼ぶ。バイパス切換弁１６を通過した流
ｙｇはオリフィス２０と低圧リリーフ２１をもつ圧力発
生装置１７により通過流量に見合ったパイロット圧力を
発生させ、そのパイロット圧力はポンプ吐出流を制御信
号として制御室に接続され、パイロット圧力の高い時は
ポンプ吐出流量を最小とし、逆に低い時は最大となるよ
うに設定されている。なお、１２はメインリリーフ弁で
あり、回路圧力の異常ト昇を防止する。10 is a pump whose discharge flow rate is controlled by a pilot signal, and the hydraulic oil discharged from this pump 10 is connected to the supply passage 13 of the directional control valve 12, and a part of the flow rate is fl
After passing through the bypass switching valve 16 via the it% control valve 14, the oil passes through the pressure generator 17 and is discharged into the tank 23. The direction switching valve 12 controls the direction of the cylinder 18 connected to the load W by its operation, and the flow rate control valve 14 is controlled by the differential pressure between the upper side pressure and the downstream side pressure of the bypass switching valve 16, When the bypass opening area of the switching valve 16 is large (when the differential pressure is small), it closes against the compression spring 19, and the flow rate is proportional to the bypass opening area regardless of the pressure in the supply passage 13. can pass. The bypass switching valve 16 has a maximum opening in neutral, closes off its passage at the end of the spool stroke, and has an optimal opening area in the middle of the stroke in relation to the flow 7.1 control valve 14. In addition, the directional switching valves 12 and 7< and the Ipanu switching valve 16 are connected, and hereinafter these will be collectively referred to as 1. It is called an IJ switching valve. The flow yg that has passed through the bypass switching valve 16 is generated by a pressure generator 17 having an orifice 20 and a low pressure relief 21 to generate a pilot pressure commensurate with the flow rate, and the pilot pressure is connected to a control room using the pump discharge flow as a control signal. When the pilot pressure is high, the pump discharge flow rate is set to the minimum, and when the pilot pressure is low, the pump discharge flow rate is set to the maximum. Note that 12 is a main relief valve, which prevents an abnormal rise in circuit pressure.
以下、作動について説明する。The operation will be explained below.
切換弁中立時のポンプからの吐出流量は流量制御弁１４
．バイパス切換弁１６を通過して圧力発生装２１１７に
流れるが、バイパス切換弁１６の開口面積が大であるの
で通過流量も多くパイロ−ｙ ト圧力が高くなり、ポン
プ流量を減少させポンプ流量が最小となるように通ｉＭ
流量（ポンプ最小吐出流量）およびパイロット圧力が設
定されている。The discharge flow rate from the pump when the switching valve is in the neutral state is determined by the flow rate control valve 14.
．． The flow passes through the bypass switching valve 16 and flows to the pressure generator 2117, but since the opening area of the bypass switching valve 16 is large, the amount of flow passing through is large and the pilot pressure increases, reducing the pump flow rate and minimizing the pump flow rate. So that it becomes iM
The flow rate (minimum pump discharge flow rate) and pilot pressure are set.
次に切換弁ストローク途中では、ポンプ吐出流Ｗは供給
通路１３からシリンダ１８へ通油されると同時に流量制
御弁１４を通ってバイパス切換弁１６に流れるが、その
バイパス切換弁１６が絞られているために通過流量が減
少し、従って圧力発生装、１１７によるパイロット圧力
が下がるのでポンプ吐出流量は増大する。ここでバイパ
ス切換弁Ｉ６を通過する流量は開口面積に応じて一定流
量となるように流ｆ制御弁１４が設置されているので、
供給通路１３の負荷圧力（シリンダ負荷圧力）に関係な
く一定流量となる。従って、切換弁ストローク位置に応
じてバイパス流量は負荷圧に関係することなく一定流量
となるので、ポンプ吐出制御用のパイロット圧カ一定お
よび吐出流ｉ−定となり、供給通路１３からシリンダ１
８への流量（ポンプ吐出流量−バイパス流量）も負荷圧
に関係なく切換弁ストローク位置に応じた一定流量とな
る。Next, during the switching valve stroke, the pump discharge flow W passes from the supply passage 13 to the cylinder 18 and at the same time flows through the flow control valve 14 to the bypass switching valve 16, but the bypass switching valve 16 is throttled. Because of this, the passing flow rate decreases, and the pilot pressure by the pressure generator 117 decreases, so the pump discharge flow rate increases. Here, the flow f control valve 14 is installed so that the flow rate passing through the bypass switching valve I6 is constant according to the opening area.
The flow rate is constant regardless of the load pressure of the supply passage 13 (cylinder load pressure). Therefore, the bypass flow rate becomes a constant flow rate regardless of the load pressure depending on the switching valve stroke position, so the pilot pressure for pump discharge control becomes constant and the discharge flow i-constant, and from the supply passage 13 to the cylinder 1.
The flow rate to 8 (pump discharge flow rate - bypass flow rate) also becomes a constant flow rate depending on the switching valve stroke position regardless of the load pressure.
次に切換弁を図において左方向に操作し、負荷Ｗが大き
く供給通路１３の流量が不足してキャビテーションが発
生した場合、ポンプ吐出流量は負荷の小さい方のシリン
ダポート側に流れ込みバイパス切換弁１６への流量が少
なくなるとパイロット圧力が下がりポンプ吐出流量は増
大し充分にシリンダへ流量を供給できるようにポンプ吐
出流量制御するのでキャビテーションの発生を押えるこ
とができる。Next, operate the switching valve to the left in the figure, and if the load W is large and the flow rate in the supply passage 13 is insufficient and cavitation occurs, the pump discharge flow will flow to the cylinder port side with the smaller load, bypass switching valve 16 When the flow rate to the cylinder decreases, the pilot pressure decreases and the pump discharge flow rate increases.Since the pump discharge flow rate is controlled so that a sufficient flow rate can be supplied to the cylinder, the occurrence of cavitation can be suppressed.
切換弁中立時もまたある程度の最小流量をポンプが吐出
しているので同様な効果がある。特にキャビテーション
を防止するメイクアップ回路を圧力発生装置前に設けれ
ばさらに効果がある。When the switching valve is in the neutral position, the pump is also discharging a certain minimum flow rate, so a similar effect can be obtained. In particular, it will be even more effective if a make-up circuit to prevent cavitation is provided in front of the pressure generator.
また、ポンプ応答遅れによるサージ圧もバイパス通路で
吸収でき、さらに、切換弁中立時もある程度の吐出流量
を持っていることにより急激に操作した時の応答遅れも
比較的少ない。In addition, surge pressure due to pump response delay can be absorbed by the bypass passage, and furthermore, since the switching valve has a certain amount of discharge flow rate even when it is in the neutral state, response delay when suddenly operated is relatively small.
第２図は他の実施例で、ポジティブ流量制御されたもの
であり、切換弁ストローク途中でのキャビテーションに
対してはポンプ吐出流量が外部パイロット信号によって
決定されるので多少劣るが従来技術の例のパワーマツチ
システムのようにボンブ吐出流量を減じることはない。Figure 2 shows another embodiment in which positive flow rate control is performed, and the pump discharge flow rate is determined by an external pilot signal in response to cavitation during the switching valve stroke, so it is slightly inferior to the prior art example. It does not reduce the bomb discharge flow rate like the Power Match system.
その他の効果は前述のネガティブ流量制御の場合と同じ
である。なお、第３図はネガティブ涼暖制御されたもの
で多連弁となった場合の実施例を示しているが、多連弁
となってもそれぞれの切換弁のストローク位置に応じて
ポンプ吐出流量が決定されるため、最大負荷を検出する
シャトルバルブなどが不必要となり構造が筒中である。Other effects are the same as in the case of negative flow rate control described above. Note that Fig. 3 shows an example in which negative cooling/warming control is applied and the valve is a multiple valve, but even if the valve is a multiple valve, the pump discharge flow rate will vary depending on the stroke position of each switching valve. is determined, so there is no need for a shuttle valve to detect the maximum load, and the structure is in the cylinder.
［発明の効果］
本発明は以上説明したように、ポンプ吐出流量制御を行
なう油圧回路において、ポンプ吐出流量の−・部を流量
制御弁を介してバイパス切換弁に通油することにより、
負荷圧に関係なく最適なメータリング波埴を得ることが
できると共に、キャビテーションを防止し、応答性を良
くし、また構造を簡単にしてコストダウンにつながる等
々の効果がある。[Effects of the Invention] As explained above, the present invention, in a hydraulic circuit that controls the pump discharge flow rate, allows - part of the pump discharge flow rate to flow through the flow rate control valve to the bypass switching valve.
It is possible to obtain an optimal metering wave regardless of the load pressure, and also has the following effects: cavitation is prevented, responsiveness is improved, and the structure is simplified, leading to cost reduction.
第１図はネガティブ流ｌ制御とした本発明の一実施例の
油圧回路図、第２図はポジティブ流量制御とした本発明
の他の実施例の油圧回路図、第３図はネガティブ流量制
御としたもので多連弁の場合の本発明の他の実施例の油
圧回路図、第４図は従来技術の実施例としてダイキンパ
ワーマツチシステムの油圧回路図である。
１０・・・ポンプ、１２・・・方向切換弁、１３・・・
供給通路、１４・・・流量制御弁、１６・・・バイパス
切換弁。
１７・・・圧力発生装置、１８・・・シリンダ、１９・
・・圧縮バネ、２０・・・オリフィス、２１・・・低圧
リリーフ弁、２２・・・メインリリーフ付、２３・・・
タンク。
２４・・・パイロット信号圧力用ポンプ、２５・・・パ
イロッ） 弁、 ２６・・・シャトルバルブ、２７・・
・センタクローズ可変絞り切換弁、２８・・・アクチュ
エータ。Fig. 1 is a hydraulic circuit diagram of one embodiment of the present invention with negative flow control, Fig. 2 is a hydraulic circuit diagram of another embodiment of the present invention with positive flow control, and Fig. 3 is a hydraulic circuit diagram of another embodiment of the present invention with negative flow control. FIG. 4 is a hydraulic circuit diagram of another embodiment of the present invention in the case of a multiple valve, and FIG. 4 is a hydraulic circuit diagram of a Daikin Power Match system as an embodiment of the prior art. 10... Pump, 12... Directional switching valve, 13...
Supply passage, 14...flow control valve, 16...bypass switching valve. 17...Pressure generator, 18...Cylinder, 19.
...Compression spring, 20...Orifice, 21...Low pressure relief valve, 22...With main relief, 23...
tank. 24...Pilot signal pressure pump, 25...Pilot) valve, 26...Shuttle valve, 27...
- Center close variable throttle switching valve, 28...actuator.
Claims (3)
と、パイロット信号により吐出流量を増減し得るポンプ
と、前記メータリング用バイパス切換弁の最上流に設け
られた流量制御弁とから成り、前記ポンプからの吐出流
量を前記方向切換弁に接続すると共に一部流量を前記流
量制御弁を介して前記メータリング用バイパス切換弁に
通油し、該バイパス切換弁の開口面積により前記流量制
御弁を制御する構成とし、前記方向切換弁および前記バ
イパス切換弁の中立時のポンプ吐出流量を最小となるよ
うにパイロット信号を設定することを特徴とする負荷圧
補償ポンプ吐出流量制御回路。(1) Consisting of a directional switching valve, a bypass switching valve for metering, a pump that can increase or decrease the discharge flow rate by a pilot signal, and a flow rate control valve provided most upstream of the bypass switching valve for metering, The discharge flow rate from the pump is connected to the directional switching valve, and a part of the flow rate is passed through the flow rate control valve to the metering bypass switching valve, and the flow rate control valve is controlled by the opening area of the bypass switching valve. A load pressure compensating pump discharge flow rate control circuit, characterized in that the load pressure compensation pump discharge flow rate control circuit is configured to control the load pressure compensation pump discharge flow rate, and sets a pilot signal so that the pump discharge flow rate when the directional switching valve and the bypass switching valve are in the neutral state is minimized.
パス切換弁の最下流に圧力発生装置を設け、該圧力発生
装置の上流よりポンプ吐出流量制御用パイロット信号を
取り出し、前記ポンプをネガティブ流量制御してなる負
荷圧補償ポンプ吐出流量制御回路。(2) In claim 1, a pressure generating device is provided at the most downstream of the bypass switching valve, and a pilot signal for controlling the pump discharge flow rate is taken out from upstream of the pressure generating device, and the pump is controlled to have a negative flow rate. Load pressure compensation pump discharge flow rate control circuit.
切換弁および前記バイパス切換弁がパイロット信号によ
り操作されるように構成し、パイロット信号の最大ポン
プ吐出流量制御用パイロット信号を取り出し、前記ポン
プをポジティブ流量制御してなる負荷圧補償ポンプ吐出
流量制御回路。(3) In claim 1, the directional switching valve and the bypass switching valve are configured to be operated by a pilot signal, and a pilot signal for controlling a maximum pump discharge flow rate is extracted from the pilot signal, and the directional switching valve and the bypass switching valve are operated by a pilot signal. The positive flow rate control becomes the load pressure compensation pump discharge flow control circuit.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP10494488A JP2631125B2 (en) | 1988-04-27 | 1988-04-27 | Load pressure compensation pump discharge flow control circuit |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP10494488A JP2631125B2 (en) | 1988-04-27 | 1988-04-27 | Load pressure compensation pump discharge flow control circuit |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPH01275902A true JPH01275902A (en) | 1989-11-06 |
| JP2631125B2 JP2631125B2 (en) | 1997-07-16 |
Family
ID=14394201
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP10494488A Expired - Fee Related JP2631125B2 (en) | 1988-04-27 | 1988-04-27 | Load pressure compensation pump discharge flow control circuit |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JP2631125B2 (en) |
Cited By (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US5277027A (en) * | 1991-04-15 | 1994-01-11 | Hitachi Construction Machinery Co., Ltd. | Hydraulic drive system with pressure compensting valve |
| US5528911A (en) * | 1992-04-04 | 1996-06-25 | Mannesmann Rexroth Gmbh | Hydraulic control apparatus for a plurality of users |
| US5720168A (en) * | 1994-02-26 | 1998-02-24 | Mannesmann Rexroth Gmbh | Control device for a hydraulic pump |
| WO1998038429A1 (en) * | 1997-02-27 | 1998-09-03 | Hitachi Construction Machinery Co., Ltd. | Hydraulic drive device and direction switchover valve for hydraulic machine |
| WO2013042484A1 (en) * | 2011-09-21 | 2013-03-28 | 住友重機械工業株式会社 | Hydraulic control device and hydraulic control method |
-
1988
- 1988-04-27 JP JP10494488A patent/JP2631125B2/en not_active Expired - Fee Related
Cited By (11)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US5277027A (en) * | 1991-04-15 | 1994-01-11 | Hitachi Construction Machinery Co., Ltd. | Hydraulic drive system with pressure compensting valve |
| US5528911A (en) * | 1992-04-04 | 1996-06-25 | Mannesmann Rexroth Gmbh | Hydraulic control apparatus for a plurality of users |
| US5720168A (en) * | 1994-02-26 | 1998-02-24 | Mannesmann Rexroth Gmbh | Control device for a hydraulic pump |
| WO1998038429A1 (en) * | 1997-02-27 | 1998-09-03 | Hitachi Construction Machinery Co., Ltd. | Hydraulic drive device and direction switchover valve for hydraulic machine |
| US6212886B1 (en) | 1997-02-27 | 2001-04-10 | Hitachi Construction Machinery Co., Ltd. | Hydraulic drive system and directional control valve apparatus in hydraulic machine |
| EP0921320A4 (en) * | 1997-02-27 | 2003-02-05 | Hitachi Construction Machinery | HYDRAULIC TRANSMISSION AND REVERSE VALVE FOR HYDRAULIC MACHINE |
| WO2013042484A1 (en) * | 2011-09-21 | 2013-03-28 | 住友重機械工業株式会社 | Hydraulic control device and hydraulic control method |
| JP2013068256A (en) * | 2011-09-21 | 2013-04-18 | Sumitomo Heavy Ind Ltd | Hydraulic control device and hydraulic control method |
| CN103765016A (en) * | 2011-09-21 | 2014-04-30 | 住友重机械工业株式会社 | Hydraulic control device and hydraulic control method |
| US9784368B2 (en) | 2011-09-21 | 2017-10-10 | Sumitomo Heavy Industries, Ltd. | Hydraulic control apparatus and method |
| US10393260B2 (en) | 2011-09-21 | 2019-08-27 | Sumitomo Heavy Industries, Ltd. | Hydraulic control apparatus and method |
Also Published As
| Publication number | Publication date |
|---|---|
| JP2631125B2 (en) | 1997-07-16 |
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