JPH04119604U - Load sensing hydraulic circuit - Google Patents
Load sensing hydraulic circuitInfo
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- JPH04119604U JPH04119604U JP2308891U JP2308891U JPH04119604U JP H04119604 U JPH04119604 U JP H04119604U JP 2308891 U JP2308891 U JP 2308891U JP 2308891 U JP2308891 U JP 2308891U JP H04119604 U JPH04119604 U JP H04119604U
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- pressure
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- load
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Abstract
(57)【要約】
【目的】 ロードセンシング油圧回路に於いて、方向制
御弁の要求流量の合計が油圧ポンプの最大吐出量を超え
た場合でも、アクチュエータの負荷圧差による干渉を防
止して複合操作性を向上させる。
【構成】 油圧ポンプの吐出圧とアクチュエータの最大
負荷圧との差に比例した２次圧を発生する第２の制御弁
を設ける。この第２の制御弁の２次圧をアクチュエータ
の負荷圧と共に圧力補償弁の一端側へ導通させ、方向制
御弁の１次圧を圧力補償弁の他端側へ導通して対抗させ
る。
(57) [Summary] [Purpose] In a load sensing hydraulic circuit, even if the total required flow rate of the directional control valve exceeds the maximum discharge amount of the hydraulic pump, it is possible to prevent interference due to the load pressure difference of the actuator and perform complex operation. Improve your sexuality. [Structure] A second control valve is provided that generates a secondary pressure proportional to the difference between the discharge pressure of the hydraulic pump and the maximum load pressure of the actuator. The secondary pressure of the second control valve is conducted to one end side of the pressure compensation valve together with the load pressure of the actuator, and the primary pressure of the directional control valve is conducted to the other end side of the pressure compensation valve so as to oppose each other.
Description
【０００１】0001
この考案は、アクチュエータの負荷圧に応じて油圧ポンプの吐出量を増減する ロードセンシング油圧回路に関するものである。 This idea increases or decreases the discharge volume of the hydraulic pump depending on the load pressure of the actuator. The present invention relates to a load sensing hydraulic circuit.
【０００２】0002
従来のロードセンシング油圧回路を図２に示す。１は可変容量形の油圧ポンプ であり、２及び３はアクチュエータ、４及び５はアクチュエータに供給する圧力 油の方向を切り替える方向制御弁、６及び７はアクチュエータに供給する圧力油 の流量を制御する圧力補償弁、８はアクチュエータの負荷圧に応じて油圧ポンプ １の吐出量を制御する制御弁である。 A conventional load sensing hydraulic circuit is shown in FIG. 1 is a variable displacement hydraulic pump 2 and 3 are the actuators, and 4 and 5 are the pressures supplied to the actuators. Directional control valve that switches the direction of oil, 6 and 7 are pressure oil that supplies the actuator 8 is a hydraulic pump according to the load pressure of the actuator. This is a control valve that controls the discharge amount of 1.
【０００３】 前記方向制御弁４及び５はクローズドセンタ形であり、アクチュエータの負荷 圧を検出できるように制御絞りの下流圧ＰL を導出させている。制御弁８の一端 にはアクチュエータの最大負荷圧ＰLMAXとばね９の力ＦS の和が作用し、制御弁 ８の他端には油圧ポンプの吐出圧ＰP が作用するので、アクチュエータの最大負 荷圧ＰLMAXの変化に応じてポンプ１の吐出量が増減する。そして、方向制御弁４ 及び５を同時に操作してアクチュエータ２及び３を作動する場合、例えば一方の アクチュエータ２の負荷圧が他方のアクチュエータ３の負荷圧より小となったと きは、方向制御弁４は単独で操作したときより流量が大となる。[0003]The directional control valves 4 and 5 are of a closed center type, and a downstream pressure P L of the control throttle is derived so that the load pressure of the actuator can be detected. The sum of the maximum load pressure P LMAX of the actuator and the force F S of the spring 9 acts on one end of the control valve 8, and the discharge pressure P P of the hydraulic pump acts on the other end of the control valve 8. The discharge amount of the pump 1 increases or decreases according to changes in the load pressure P LMAX . When operating the actuators 2 and 3 by simultaneously operating the directional control valves 4 and 5, for example, when the load pressure on one actuator 2 becomes smaller than the load pressure on the other actuator 3, the directional control valve 4 The flow rate is larger than when operated alone.
【０００４】 前記圧力補償弁６の一端には制御絞りの上流圧ＰU が作用し、圧力補償弁６の 他端には制御絞りの下流圧ＰL とばね１０の力ＦA の和が作用するので、制御絞 りの前後の圧力差が一定になるように制御して、負荷圧が小であるアクチュエー タ２へ多量の圧力油が流れることを防止している。 一般に制御絞り内を通過する流量Ｑは次式で表され、The upstream pressure P U of the control throttle acts on one end of the pressure compensation valve 6, and the sum of the downstream pressure P L of the control throttle and the force F A of the spring 10 acts on the other end of the pressure compensation valve 6. Therefore, the pressure difference before and after the control throttle is controlled to be constant to prevent a large amount of pressure oil from flowing to the actuator 2 where the load pressure is small. Generally, the flow rate Q passing through the control restrictor is expressed by the following formula,
【０００５】[0005]
【数１】 [Math 1]
【０００６】 方向制御弁４又は５の流量も（１式）のＱで表される。そして、圧力補償弁６又 は７はその両端の圧力が等しくなるように制御するので、[0006] The flow rate of the directional control valve 4 or 5 is also represented by Q in equation (1). And the pressure compensating valve 6 prongs 7 is controlled so that the pressure at both ends is equal, so
【０００７】[0007]
【数２】 [Math 2]
【０００８】 となる。従って、（１式）及び（２式）から[0008] becomes. Therefore, from (Equation 1) and (Equation 2),
【０００９】[0009]
【数３】 [Math 3]
【００１０】 となり、圧力補償弁６又は７のばねの力ＦA が一定であることから、方向制御弁 ４又は５の流量Ｑは制御絞りの開口面積Ａによって決定される。Since the spring force F A of the pressure compensation valve 6 or 7 is constant, the flow rate Q of the directional control valve 4 or 5 is determined by the opening area A of the control throttle.
【００１１】[0011]
従来のロードセンシング油圧回路に於いて、全てのアクチュエータ２，３を同 時に駆動したとき、アクチュエータ２，３の夫々の要求流量（方向制御弁４又は ５の制御絞りの開口面積Ａにより決定）の和が油圧ポンプ１の最大吐出量以下で ある場合には、制御弁８が正常に作動してポンプの吐出圧ＰP を変化させ、油圧 ポンプ１の吐出量を増減させる。従って、圧力補償弁６又は７の作用により、（ ３式）に示したように方向制御弁４又は５の流量Ｑが制御されて、一方のアクチ ュエータへ多量の圧力油が流れないようにしている。In a conventional load sensing hydraulic circuit, when all the actuators 2 and 3 are driven simultaneously, the sum of the required flow rates of each of the actuators 2 and 3 (determined by the opening area A of the control throttle of the directional control valve 4 or 5) is less than the maximum discharge amount of the hydraulic pump 1, the control valve 8 operates normally to change the pump discharge pressure P P and increase or decrease the discharge amount of the hydraulic pump 1. Therefore, by the action of the pressure compensation valve 6 or 7, the flow rate Q of the directional control valve 4 or 5 is controlled as shown in equation (3) to prevent a large amount of pressure oil from flowing to one of the actuators. .
【００１２】 然し、アクチュエータ２，３の夫々の要求流量の和が油圧ポンプ１の最大吐出 量を超えた場合には、圧力補償弁６，７によって圧力補償し切れず、圧力油の大 半が負荷小側のアクチュエータで消費されることがある。然るときは、制御弁８ が作動しなくなってポンプの吐出圧ＰP を負荷大側のアクチュエータの圧力より 高く維持できなくなり、この負荷大側のアクチュエータを駆動できなくなる。即 ち、アクチュエータの負荷圧差に基づく負荷干渉を生じ易かった。However, if the sum of the required flow rates of the actuators 2 and 3 exceeds the maximum discharge amount of the hydraulic pump 1, the pressure cannot be compensated by the pressure compensation valves 6 and 7, and most of the pressure oil is under load. It may be consumed by the smaller actuator. In such a case, the control valve 8 stops operating and the pump discharge pressure P P cannot be maintained higher than the pressure of the actuator on the larger load side, making it impossible to drive the actuator on the larger load side. That is, load interference was likely to occur due to the difference in load pressure between the actuators.
【００１３】 そこで、斯かる不具合を解消し、方向制御弁の要求流量の和が油圧ポンプの最 大吐出量を超えたときであっても、各アクチュエータの駆動を継続して行えるよ うにするために解決すべき技術的課題が生じてくるのであり、本考案はこの課題 を解決することを目的とする。[0013] Therefore, we solved this problem and made sure that the sum of the required flow rates of the directional control valves was the maximum of the hydraulic pump. Each actuator can continue to be driven even when the large discharge amount is exceeded. There are technical issues that need to be solved in order to The purpose is to solve the problem.
【００１４】[0014]
この考案は上記目的を達成するために提案されたものであり、可変容量形の油 圧ポンプと、この油圧ポンプから吐出される圧力油により駆動される複数のアク チュエータと、該アクチュエータに供給する圧力油の方向を切り替える方向制御 弁と、アクチュエータに供給する圧力油の流量を制御する圧力補償弁と、アクチ ュエータの負荷圧に応じて前記油圧ポンプの吐出量を制御する制御弁とからなる ロードセンシング油圧回路に於いて、油圧ポンプの吐出圧とアクチュエータの最 大負荷圧との差に比例した２次圧を発生する第２の制御弁を設け、該第２の制御 弁の２次圧をアクチュエータの負荷圧と共に前記圧力補償弁の開放側のパイロッ トポートへ導通し、圧力補償弁の閉鎖側のパイロットポートへ方向制御弁の１次 圧を導通して対抗させたことを特徴とするロードセンシング油圧回路を提供する ものである。 This idea was proposed to achieve the above purpose, and is a variable displacement type oil A pressure pump and multiple actuators driven by the pressure oil discharged from the hydraulic pump. Directional control to switch the direction of the tuator and the pressure oil supplied to the actuator valve, a pressure compensation valve that controls the flow rate of pressure oil supplied to the actuator, and an actuator. and a control valve that controls the discharge amount of the hydraulic pump according to the load pressure of the hydraulic pump. In the load sensing hydraulic circuit, the hydraulic pump discharge pressure and the actuator maximum A second control valve is provided that generates a secondary pressure proportional to the difference from the large load pressure, and the second control valve The secondary pressure of the valve is combined with the load pressure of the actuator by the pilot on the open side of the pressure compensation valve. The primary port of the directional control valve is connected to the pilot port on the closing side of the pressure compensation valve. To provide a load sensing hydraulic circuit characterized in that pressure is conducted and opposed. It is something.
【００１５】[0015]
第２の制御弁の１次側には、油圧ポンプの吐出圧とアクチュエータの最大負荷 圧とが対抗して作用する。従って、第２の制御弁の２次側には、前記油圧ポンプ の吐出圧とアクチュエータの最大負荷圧の差に比例した２次圧が発生する。この 第２の制御弁の２次圧をアクチュエータの負荷圧と共に圧力補償弁の開放側のパ イロットポートへ導通し、圧力補償弁の閉鎖側のパイロットポートへ方向制御弁 の１次圧を導通して対抗させてあるので、圧力補償弁は前記２次圧とアクチュエ ータの負荷圧の和と、方向制御弁の１次圧とが等しくなるように作用する。即ち 、方向制御弁の流量は、油圧ポンプの吐出圧とアクチュエータの最大負荷圧の差 及び制御絞りの開口面積とで決定される。 The primary side of the second control valve has the hydraulic pump discharge pressure and the maximum load of the actuator. The pressure acts in opposition. Therefore, the hydraulic pump is connected to the secondary side of the second control valve. A secondary pressure is generated that is proportional to the difference between the discharge pressure of the actuator and the maximum load pressure of the actuator. this The secondary pressure of the second control valve is applied to the opening side of the pressure compensation valve along with the load pressure of the actuator. Connects to the pilot port and connects the pilot port on the closing side of the pressure compensation valve to the directional control valve. Since the primary pressure of the actuator is conducted and opposed, the pressure compensating valve It acts so that the sum of the load pressures of the motor and the primary pressure of the directional control valve become equal. That is, , the flow rate of the directional control valve is the difference between the discharge pressure of the hydraulic pump and the maximum load pressure of the actuator. and the aperture area of the control diaphragm.
【００１６】 アクチュエータの要求流量の和が油圧ポンプの最大吐出量を超えた場合には、 制御弁が作用しなくなり油圧ポンプの吐出圧とアクチュエータの最大負荷圧の差 が小となる。従って、一方のアクチュエータの負荷圧が他方のアクチュエータの 負荷圧より小となったとき、負荷圧小側と負荷圧大側の双方の方向制御弁の流量 は制御絞りの開口面積に比例し、前述した油圧ポンプの吐出圧とアクチュエータ の最大負荷圧の差は、双方の方向制御弁の合計流量と油圧ポンプの最大吐出量と が等しくなるまで小さくなり、アクチュエータの負荷圧差による負荷干渉を防止 できる。[0016] If the sum of the required flow rates of the actuators exceeds the maximum discharge rate of the hydraulic pump, The control valve stops working and the difference between the discharge pressure of the hydraulic pump and the maximum load pressure of the actuator becomes small. Therefore, the load pressure on one actuator is equal to the load pressure on the other actuator. When the pressure is lower than the load pressure, the flow rate of the directional control valves on both the low load pressure side and the high load pressure side is proportional to the aperture area of the control throttle, and is proportional to the discharge pressure of the hydraulic pump and actuator described above. The difference in the maximum load pressure is the total flow rate of both directional control valves and the maximum discharge rate of the hydraulic pump. are reduced until they are equal, preventing load interference due to actuator load pressure differences. can.
【００１７】[0017]
以下、本考案の一実施例を図面に従って詳述する。尚、説明の都合上、従来の 回路構成も同時に説明する。図１はロードセンシング油圧回路を示し、１１は可 変容量形の油圧ポンプであり、１２及び１３はアクチュエータ、１４及び１５は アクチュエータに供給する圧力油の方向を切り替える方向制御弁、１６及び１７ はアクチュエータに供給する圧力油の流量を制御する圧力補償弁、１８はアクチ ュエータの負荷圧に応じて油圧ポンプ１１の吐出量を制御する制御弁、１９は油 圧ポンプ１１の吐出圧とアクチュエータの最大負荷圧との差に応じた２次圧を発 生する第２の制御弁である。 Hereinafter, one embodiment of the present invention will be described in detail with reference to the drawings. For convenience of explanation, the conventional The circuit configuration will also be explained at the same time. Figure 1 shows the load sensing hydraulic circuit; It is a variable displacement hydraulic pump, 12 and 13 are actuators, 14 and 15 are actuators. Directional control valves 16 and 17 that switch the direction of pressure oil supplied to the actuator 18 is a pressure compensation valve that controls the flow rate of pressure oil supplied to the actuator; 19 is an oil control valve that controls the discharge amount of the hydraulic pump 11 according to the load pressure of the evaporator; Generates secondary pressure according to the difference between the discharge pressure of the pressure pump 11 and the maximum load pressure of the actuator. This is the second control valve that operates.
【００１８】 油圧ポンプ１１の吐出口と圧力補償弁１６，１７とは管路２０で接続され、管 路２０から管路２１と管路２２が分岐して、制御弁１８の一端側及び第２の制御 弁１９の一端側へポンプの吐出圧ＰP を導出する。方向制御弁１４及び１５はク ローズドセンタ形であり、アクチュエータの負荷圧を検出できるように制御絞り の下流側にパイロット管路２３及び２４を設けてある。このパイロット管路２３ 及び２４を圧力補償弁１６及び１７の開放側のパイロットポートに接続してアク チュエータの負荷圧（制御絞りの下流圧ＰL ）を導出すると共に、シャトル弁２ ５によりパイロット管路２３及び２４の負荷圧（制御絞りの下流圧ＰL ）のうち 高圧側を選択して、パイロット管路２６へアクチュエータ２又は３で発生した最 大負荷圧ＰLMAXを導出する。The discharge port of the hydraulic pump 11 and the pressure compensating valves 16 and 17 are connected by a conduit 20, and a conduit 21 and a conduit 22 are branched from the conduit 20, and one end of the control valve 18 and a second end of the control valve 18 are connected to each other. The pump discharge pressure P P is derived to one end side of the control valve 19 . The directional control valves 14 and 15 are of a closed center type, and pilot lines 23 and 24 are provided downstream of the control throttle so that the load pressure of the actuator can be detected. The pilot pipes 23 and 24 are connected to the open side pilot ports of the pressure compensating valves 16 and 17 to derive the load pressure of the actuator (downstream pressure P L of the control throttle), and the pilot pipes are connected to the pilot pipes by the shuttle valves 25. The high pressure side is selected from among the load pressures 23 and 24 (downstream pressure P L of the control throttle), and the maximum load pressure P LMAX generated by the actuator 2 or 3 is guided to the pilot pipe 26 .
【００１９】 このアクチュエータの最大負荷圧ＰLMAXは第２の制御弁１９の他端側へも導出 し、該第２の制御弁１９はポンプの吐出圧ＰP とアクチュエータの最大負荷圧Ｐ LMAX とを対抗させてある。図示したように、第２の制御弁１９のスプールが１９ ａの位置にあるときは、ポンプの吐出圧ＰP の一部がパイロット管路２８へ流入 し、圧力補償弁１６及び１７の開放側のパイロットポートへ導通すると共に、パ イロット管路２８から分岐したパイロット管路２９により第２の制御弁１９の他 端側へ導通する。更に、第２の制御弁１９のスプールが１９ｂの位置になったと きは、パイロット管路２８の圧力油を管路３０を通して油タンク３１へ連通する ようにしてある。[0019] Maximum load pressure P of this actuatorLMAXis also led out to the other end side of the second control valve 19. However, the second control valve 19 controls the discharge pressure P of the pump.Pand the maximum load pressure P of the actuator LMAX are compared with. As shown, the spool of the second control valve 19 is When in position a, the pump discharge pressure PPA part of the flow into the pilot pipe 28 conducts to the open side pilot ports of pressure compensating valves 16 and 17, and A pilot line 29 branched from the pilot line 28 connects the second control valve 19 and other valves. Conducts to the end side. Furthermore, when the spool of the second control valve 19 is at the position 19b, In this case, the pressure oil in the pilot pipe 28 is communicated to the oil tank 31 through the pipe 30. It's like this.
【００２０】 従って、第２の制御弁１９はポンプの吐出圧ＰP とアクチュエータの最大負荷 圧ＰLMAXとの差に比例した２次圧ＰC が発生し、第２の制御弁１９が釣り合った ときはTherefore, the second control valve 19 generates a secondary pressure P C proportional to the difference between the pump discharge pressure P P and the maximum load pressure P LMAX of the actuator, and the second control valve 19 is balanced. when
【００２１】[0021]
【数４】 [Math 4]
【００２２】 となる。従って、２次圧ＰC は次式で表される。[0022] Therefore, the secondary pressure P C is expressed by the following formula.
【００２３】[0023]
【数５】 [Math 5]
【００２４】 一方、圧力補償弁１６及び１７の開放側のパイロットポートには、パイロット 管路２３又は２４により制御絞りの下流圧ＰL （アクチュエータの負荷圧）が導 通されると共に、パイロット管路２８により第２の制御弁１９の２次圧ＰC が導 通される。又、圧力補償弁１６及び１７の閉鎖側のパイロットポートには制御絞 りの上流圧ＰU （方向制御弁の１次圧）を導通して対抗させてあり、圧力補償弁 １６又は１７が釣り合ったときはOn the other hand, the downstream pressure P L of the control throttle (load pressure of the actuator) is conducted to the open side pilot ports of the pressure compensation valves 16 and 17 through the pilot line 23 or 24, and the pilot line 28 Therefore, the secondary pressure P C of the second control valve 19 is conducted. In addition, the pilot ports on the closing side of the pressure compensation valves 16 and 17 are connected to the upstream pressure P U (primary pressure of the directional control valve) of the control throttle so that the pressure compensation valves 16 and 17 are balanced. when
【００２５】[0025]
【数６】 [Math 6]
【００２６】 となる。従って、（５式）によるＰC を（６式）へ代入すれば、ＰU は次式で表 される。[0026] Therefore, by substituting P C from equation (5) into equation (6), P U is expressed by the following equation.
【００２７】[0027]
【数７】 [Math 7]
【００２８】 前述したように、方向制御弁１４又は１５の流量Ｑは、[0028] As mentioned above, the flow rate Q of the directional control valve 14 or 15 is
【００２９】[0029]
【数８】 [Math. 8]
【００３０】 で表され、（７式）のＰU を（８式）へ代入すれば、[0030] If P U of (7) is substituted into (8), we get
【００３１】[0031]
【数９】 [Math. 9]
【００３２】[0032]
【数１０】 [Math. 10]
【００３３】 となる。即ち、方向制御弁１４又は１５の流量Ｑは、制御絞りの開口面積Ａと、 ポンプの吐出圧ＰP とアクチュエータの最大負荷圧ＰLMAXの圧力差とで決定され る。 アクチュエータ１２及び１３を同時に駆動して、アクチュエータ１２及び１３ の夫々の要求流量の和が油圧ポンプ１１の最大吐出量以下である場合には制御弁 １８が正常に作動し、制御弁１８の他端側に設けたばね３２の力ＦS とアクチュ エータの最大負荷圧ＰLMAXの和がポンプの吐出圧ＰP に釣り合うように制御され る。即ち、[0033] That is, the flow rate Q of the directional control valve 14 or 15 is determined by the opening area A of the control throttle and the pressure difference between the pump discharge pressure P P and the maximum load pressure P LMAX of the actuator. When the actuators 12 and 13 are driven simultaneously and the sum of the required flow rates of the actuators 12 and 13 is less than or equal to the maximum discharge amount of the hydraulic pump 11, the control valve 18 operates normally and the other end of the control valve 18 The sum of the force F S of the spring 32 provided on the side and the maximum load pressure P LMAX of the actuator is controlled so as to balance the discharge pressure P P of the pump. That is,
【００３４】[0034]
【数１１】 [Math. 11]
【００３５】 となり、ＰLMAXを左辺へ移項すれば[0035] Then, if we move P LMAX to the left side, we get
【００３６】[0036]
【数１２】 [Math. 12]
【００３７】 となる。従って、（１０式）及び（１２式）から[0037] becomes. Therefore, from (Equation 10) and (Equation 12),
【００３８】[0038]
【数１３】 [Math. 13]
【００３９】 となり、制御弁１８のばね３２の力ＦS が一定であることから、方向制御弁１４ 又は１５の流量Ｑは制御絞りの開口面積Ａによって決定される。 ここで、アクチュエータ１２及び１３の夫々の要求流量の和が油圧ポンプ１１ の最大吐出量を超えた場合には、前述したように制御弁１８が作動しなくなって ポンプの吐出圧ＰP とアクチュエータの最大負荷圧ＰLMAXとの差が小になる。例 えば、アクチュエータ１２の負荷圧がアクチュエータ１３の負荷圧より小である 場合、（１０式）より負荷小側の方向制御弁１４の流量Ｑ1 は、Since the force F S of the spring 32 of the control valve 18 is constant, the flow rate Q of the directional control valve 14 or 15 is determined by the opening area A of the control throttle. Here, if the sum of the required flow rates of the actuators 12 and 13 exceeds the maximum discharge amount of the hydraulic pump 11, the control valve 18 stops operating as described above, and the pump discharge pressure P and the actuator The difference from the maximum load pressure P LMAX becomes smaller. For example, when the load pressure of the actuator 12 is smaller than the load pressure of the actuator 13, the flow rate Q 1 of the directional control valve 14 on the smaller load side according to (formula 10) is:
【００４０】[0040]
【数１４】 [Math. 14]
【００４１】 で表され、負荷大側の方向制御弁１５の流量Ｑ2 は、The flow rate Q 2 of the directional control valve 15 on the larger load side is expressed as
【００４２】[0042]
【数１５】 [Math. 15]
【００４３】 で表される。即ち、負荷小側と負荷大側の方向制御弁の流量Ｑ1 ，Ｑ2 は夫々の 制御絞りの開口面積Ａ1 ，Ａ2 に比例し、ポンプの吐出圧ＰP とアクチュエータ の最大負荷圧ＰLMAXの差は、方向制御弁１４及び１５の合計流量Ｑ1 ＋Ｑ2 と油 圧ポンプ１１の最大吐出量とが等しくなるまで減少する。斯くして、複数のアク チュエータ１２及び１３を同時に駆動する複合操作が可能となる。It is expressed as follows. That is, the flow rates Q 1 and Q 2 of the directional control valves on the small load side and the large load side are proportional to the opening areas A 1 and A 2 of the respective control throttles, and the pump discharge pressure P P and the maximum load pressure P of the actuator The difference in LMAX decreases until the total flow rate Q 1 +Q 2 of the directional control valves 14 and 15 and the maximum discharge amount of the hydraulic pump 11 become equal. In this way, a combined operation in which multiple actuators 12 and 13 are driven simultaneously becomes possible.
【００４４】 尚、この考案は、この考案の精神を逸脱しない限り種々の改変を為すことがで き、そして、この考案が該改変されたものに及ぶことは当然である。[0044] This invention may be modified in various ways as long as it does not depart from the spirit of this invention. Naturally, this invention extends to the modified version.
【００４５】[0045]
この考案は上記一実施例に詳述したように、複数のアクチュエータの要求流量 の和が油圧ポンプの最大吐出量を超えた場合には、第２の制御弁により油圧ポン プの吐出圧とアクチュエータの最大負荷圧との差に比例した２次圧を圧力補償弁 のポートへ導出し、複数のアクチュエータの方向制御弁の合計流量と油圧ポンプ の最大吐出量とが等しくなるように作用する。依って、アクチュエータの負荷圧 差による干渉を防止でき、複数のアクチュエータの複合操作が安定して行える。 又、圧力補償弁のばねをなくして第２の制御弁の２次圧を使用するため、圧力補 償弁の構造を小型化することができる。 As detailed in the above-mentioned embodiment, this invention is based on the required flow rate of multiple actuators. If the sum exceeds the maximum discharge amount of the hydraulic pump, the second control valve The pressure compensation valve adjusts the secondary pressure proportional to the difference between the discharge pressure of the actuator and the maximum load pressure of the actuator. Hydraulic pump with total flow rate of directional control valve of multiple actuators leading to port of It acts so that the maximum discharge amount is equal to the maximum discharge amount. Therefore, the load pressure of the actuator Interference due to differences can be prevented, and combined operations of multiple actuators can be performed stably. In addition, since the spring of the pressure compensation valve is eliminated and the secondary pressure of the second control valve is used, the pressure compensation The structure of the reimbursement can be downsized.
【図面の簡単な説明】[Brief explanation of drawings]
【図１】本考案の一実施例なるロードセンシング油圧回
路。FIG. 1 shows a load sensing hydraulic circuit as an embodiment of the present invention.
【図２】従来例なるロードセンシング油圧回路。FIG. 2 shows a conventional load sensing hydraulic circuit.
１１ 油圧ポンプ
１２，１３ アクチュエータ
１４，１５ 方向制御弁
１６，１７ 圧力補償弁
１８ 制御弁
１９ 第２の制御弁
ＰP ポンプの吐出圧
ＰU 制御絞りの上流圧
ＰL 制御絞りの下流圧（アクチュエータの負荷
圧）
ＰLMAX アクチュエータの最大負荷圧
ＰC 第２の制御弁の２次圧11 Hydraulic pumps 12, 13 Actuators 14, 15 Directional control valves 16, 17 Pressure compensation valve 18 Control valve 19 Second control valve P P Pump discharge pressure P U Upstream pressure of control throttle P L Downstream pressure of control throttle Maximum load pressure of P LMAX actuator P C Secondary pressure of second control valve
Claims (1)
ンプから吐出される圧力油により駆動される複数のアク
チュエータと、該アクチュエータに供給する圧力油の方
向を切り替える方向制御弁と、アクチュエータに供給す
る圧力油の流量を制御する圧力補償弁と、アクチュエー
タの負荷圧に応じて前記油圧ポンプの吐出量を制御する
制御弁とからなるロードセンシング油圧回路に於いて、
油圧ポンプの吐出圧とアクチュエータの最大負荷圧との
差に比例した２次圧を発生する第２の制御弁を設け、該
第２の制御弁の２次圧をアクチュエータの負荷圧と共に
前記圧力補償弁の開放側のパイロットポートへ導通し、
圧力補償弁の閉鎖側のパイロットポートへ方向制御弁の
１次圧を導通して対抗させたことを特徴とするロードセ
ンシング油圧回路。1. A variable displacement hydraulic pump, a plurality of actuators driven by pressure oil discharged from the hydraulic pump, a directional control valve that switches the direction of the pressure oil supplied to the actuators, and a directional control valve that switches the direction of the pressure oil supplied to the actuators. In a load sensing hydraulic circuit comprising a pressure compensation valve that controls the flow rate of pressure oil and a control valve that controls the discharge amount of the hydraulic pump according to the load pressure of the actuator,
A second control valve is provided that generates a secondary pressure proportional to the difference between the discharge pressure of the hydraulic pump and the maximum load pressure of the actuator, and the secondary pressure of the second control valve is used together with the load pressure of the actuator to compensate for the pressure. Conducts to the pilot port on the open side of the valve,
A load sensing hydraulic circuit characterized in that the primary pressure of a directional control valve is conducted to and opposed to a pilot port on the closing side of a pressure compensation valve.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP1991023088U JP2526440Y2 (en) | 1991-04-09 | 1991-04-09 | Load sensing hydraulic circuit |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP1991023088U JP2526440Y2 (en) | 1991-04-09 | 1991-04-09 | Load sensing hydraulic circuit |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPH04119604U true JPH04119604U (en) | 1992-10-26 |
| JP2526440Y2 JP2526440Y2 (en) | 1997-02-19 |
Family
ID=31908423
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP1991023088U Expired - Lifetime JP2526440Y2 (en) | 1991-04-09 | 1991-04-09 | Load sensing hydraulic circuit |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JP2526440Y2 (en) |
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH09296803A (en) * | 1996-04-30 | 1997-11-18 | Nachi Fujikoshi Corp | Hydraulic driving device and proportioning pressure reducing valve for hydraulic driving device |
| WO1998022716A1 (en) * | 1996-11-15 | 1998-05-28 | Hitachi Construction Machinery Co., Ltd. | Hydraulic drive apparatus |
| JPH10205501A (en) * | 1996-11-21 | 1998-08-04 | Hitachi Constr Mach Co Ltd | Hydraulic drive device |
Families Citing this family (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| EP0877168B1 (en) * | 1996-11-21 | 2004-02-11 | Hitachi Construction Machinery Co., Ltd. | Hydraulic drive system |
| JP6815268B2 (en) | 2017-04-19 | 2021-01-20 | ヤンマーパワーテクノロジー株式会社 | Control device for hydraulic machinery |
Citations (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS6011706A (en) * | 1983-06-14 | 1985-01-22 | リンデ・アクチエンゲゼルシヤフト | Liquid pressure type apparatus having at least two working apparatuses loaded by one pump |
| JPH02213524A (en) * | 1989-02-13 | 1990-08-24 | Hitachi Constr Mach Co Ltd | Oil hydraulic circuit of work equipment |
-
1991
- 1991-04-09 JP JP1991023088U patent/JP2526440Y2/en not_active Expired - Lifetime
Patent Citations (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS6011706A (en) * | 1983-06-14 | 1985-01-22 | リンデ・アクチエンゲゼルシヤフト | Liquid pressure type apparatus having at least two working apparatuses loaded by one pump |
| JPH02213524A (en) * | 1989-02-13 | 1990-08-24 | Hitachi Constr Mach Co Ltd | Oil hydraulic circuit of work equipment |
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH09296803A (en) * | 1996-04-30 | 1997-11-18 | Nachi Fujikoshi Corp | Hydraulic driving device and proportioning pressure reducing valve for hydraulic driving device |
| WO1998022716A1 (en) * | 1996-11-15 | 1998-05-28 | Hitachi Construction Machinery Co., Ltd. | Hydraulic drive apparatus |
| JPH10205501A (en) * | 1996-11-21 | 1998-08-04 | Hitachi Constr Mach Co Ltd | Hydraulic drive device |
Also Published As
| Publication number | Publication date |
|---|---|
| JP2526440Y2 (en) | 1997-02-19 |
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