EP0191275B1 - Anti-saturation system for hydraulic control circuits for working members of earth-moving machines - Google Patents

Anti-saturation system for hydraulic control circuits for working members of earth-moving machines Download PDF

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Publication number
EP0191275B1
EP0191275B1 EP85830286A EP85830286A EP0191275B1 EP 0191275 B1 EP0191275 B1 EP 0191275B1 EP 85830286 A EP85830286 A EP 85830286A EP 85830286 A EP85830286 A EP 85830286A EP 0191275 B1 EP0191275 B1 EP 0191275B1
Authority
EP
European Patent Office
Prior art keywords
pressure
valve
working members
distributors
hydraulic
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Expired
Application number
EP85830286A
Other languages
German (de)
English (en)
French (fr)
Other versions
EP0191275A1 (en
Inventor
Piero Tha
Bernardo Sandrono
Giovanni Maria Testa
Raffaele Sandroni
Gerald Keith Warren
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.)
Vickers Systems GmbH
Trinova SpA
Original Assignee
Vickers Systems GmbH
Trinova SpA
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 Vickers Systems GmbH, Trinova SpA filed Critical Vickers Systems GmbH
Priority to AT85830286T priority Critical patent/ATE46940T1/de
Publication of EP0191275A1 publication Critical patent/EP0191275A1/en
Application granted granted Critical
Publication of EP0191275B1 publication Critical patent/EP0191275B1/en
Expired legal-status Critical Current

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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
    • F15B11/00—Servomotor systems without provision for follow-up action; Circuits therefor
    • F15B11/16—Servomotor systems without provision for follow-up action; Circuits therefor with two or more servomotors
    • F15B11/161—Servomotor systems without provision for follow-up action; Circuits therefor with two or more servomotors with sensing of servomotor demand or load
    • F15B11/166—Controlling a pilot pressure in response to the load, i.e. supply to at least one user is regulated by adjusting either the system pilot pressure or one or more of the individual pilot command pressures
    • 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
    • E02F9/2217—Hydraulic or pneumatic drives with energy recovery arrangements, e.g. using accumulators, flywheels
    • 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
    • E02F9/2232—Control of flow rate; Load sensing arrangements using one or more variable displacement pumps
    • 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
    • E02F9/226—Safety arrangements, e.g. hydraulic driven fans, preventing cavitation, leakage, overheating
    • 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
    • E02F9/2292—Systems with two or more pumps
    • 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
    • E02F9/2296—Systems with a variable displacement pump
    • 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
    • F15B11/00—Servomotor systems without provision for follow-up action; Circuits therefor
    • F15B11/16—Servomotor systems without provision for follow-up action; Circuits therefor with two or more servomotors
    • F15B11/161—Servomotor systems without provision for follow-up action; Circuits therefor with two or more servomotors with sensing of servomotor demand or load
    • F15B11/163—Servomotor systems without provision for follow-up action; Circuits therefor with two or more servomotors with sensing of servomotor demand or load for sharing the pump output equally amongst users or groups of users, e.g. using anti-saturation, pressure compensation
    • 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
    • F15B2211/00—Circuits for servomotor systems
    • F15B2211/20—Fluid pressure source, e.g. accumulator or variable axial piston pump
    • F15B2211/205—Systems with pumps
    • F15B2211/2053—Type of pump
    • F15B2211/20546—Type of pump variable capacity
    • F15B2211/20553—Type of pump variable capacity with pilot circuit, e.g. for controlling a swash plate
    • 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
    • F15B2211/00—Circuits for servomotor systems
    • F15B2211/20—Fluid pressure source, e.g. accumulator or variable axial piston pump
    • F15B2211/21—Systems with pressure sources other than pumps, e.g. with a pyrotechnical charge
    • F15B2211/212—Systems with pressure sources other than pumps, e.g. with a pyrotechnical charge the pressure sources being accumulators
    • 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
    • F15B2211/00—Circuits for servomotor systems
    • F15B2211/30—Directional control
    • F15B2211/305—Directional control characterised by the type of valves
    • F15B2211/30525—Directional control valves, e.g. 4/3-directional control valve
    • F15B2211/3053—In combination with a pressure compensating valve
    • F15B2211/30535—In combination with a pressure compensating valve the pressure compensating valve is arranged between pressure source and directional control valve
    • 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
    • F15B2211/00—Circuits for servomotor systems
    • F15B2211/30—Directional control
    • F15B2211/31—Directional control characterised by the positions of the valve element
    • F15B2211/3105—Neutral or centre positions
    • F15B2211/3111—Neutral or centre positions the pump port being closed in the centre position, e.g. so-called closed centre
    • 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
    • F15B2211/00—Circuits for servomotor systems
    • F15B2211/30—Directional control
    • F15B2211/32—Directional control characterised by the type of actuation
    • F15B2211/329—Directional control characterised by the type of actuation actuated by fluid pressure
    • 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
    • F15B2211/00—Circuits for servomotor systems
    • F15B2211/50—Pressure control
    • F15B2211/505—Pressure control characterised by the type of pressure control means
    • F15B2211/50509—Pressure control characterised by the type of pressure control means the pressure control means controlling a pressure upstream of the pressure control means
    • F15B2211/50536—Pressure control characterised by the type of pressure control means the pressure control means controlling a pressure upstream of the pressure control means using unloading valves controlling the supply pressure by diverting fluid to the return line
    • 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
    • F15B2211/00—Circuits for servomotor systems
    • F15B2211/60—Circuit components or control therefor
    • F15B2211/605—Load sensing circuits
    • F15B2211/6051—Load sensing circuits having valve means between output member and the load sensing circuit
    • F15B2211/6054—Load sensing circuits having valve means between output member and the load sensing circuit using shuttle valves
    • 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
    • F15B2211/00—Circuits for servomotor systems
    • F15B2211/70—Output members, e.g. hydraulic motors or cylinders or control therefor
    • F15B2211/705—Output members, e.g. hydraulic motors or cylinders or control therefor characterised by the type of output members or actuators
    • F15B2211/7058—Rotary output members
    • 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
    • F15B2211/00—Circuits for servomotor systems
    • F15B2211/70—Output members, e.g. hydraulic motors or cylinders or control therefor
    • F15B2211/71—Multiple output members, e.g. multiple hydraulic motors or cylinders
    • F15B2211/7142—Multiple output members, e.g. multiple hydraulic motors or cylinders the output members being arranged in multiple groups

Definitions

  • the present invention relates in general to hydraulic control circuits for working members of earth-moving machines.
  • the invention relates to hydraulic circuits with pumps and pressure-compensated distributors, of the type including a supply source of hydraulic fluid under pressure and a plurality of hydraulic working members each of which is associated with a respective hydraulic distributor having a spool which can be set with continuous adjustment by respective pilot means in three positions corresponding to movement of the working member in a first direction, stoppage, and movement in a second direction opposite the first, and pressure compensating means associated with the supply source and the distributors for keeping the difference between the pressure supplied by the source and the pressure of the working members substantially constant.
  • Hydraulic circuits of the above-mentioned type are generally known, for example, from US-A-4,343,152 and US-A-3,543,646.
  • the object of the present invention is to avoid this disadvantage and this object is achieved by providing, in a hydraulic circuit of the type described above, an anti-saturation system characterised in that it includes valve means which, in the event of a decrease in the difference between the pressure supplied by the source and the pressure of the working members, act to reduce the delivery supplied to the working members by the respective distributors.
  • valve means which, in the event of a decrease in the difference between the pressure supplied by the source and the pressure of the working members, act to reduce the delivery supplied to the working members by the respective distributors.
  • Normally such valve means are constituted by depressurising valve means.
  • the anti-saturation system allows a reduction in the delivery taken by the working members by decreasing the passage areas of the various units formed by the spools of the distributors and their respective local compensators.
  • this may be effected by the association of the depressurising valve means with either the pilot means for the distributors or the compensating means for the distributors.
  • the depressurising valve means act conveniently to reduce the maximum pilot pressure transmitted to the distributors by the hydraulic servocontrol devices.
  • the balancing pressures acting on the compensators associated with the distributors are conveniently reduced, unbalancing the compensators in such a way that they close and restrict the delivery taken by these compensators.
  • the depressurising valve means may operate automatically in response to the difference between the pressure supplied by the source and that of the working members, or they may be operated by a voluntary control in order to achieve the conditions of non-saturation of the circuit.
  • FIG. 1 illustrates schematically the essential components of a hydraulic control circuit for the working members of an earth-moving machine.
  • these working members comprise a series of hydraulic linear actuators 1 serving to operate the excavating arm (positioning-raising-penetration-reverse excavation) and a series of rotary actuators 2 for the translational movements of the excavator and rotation of the excavating arm.
  • the actuators 1 and 2 are arranged in two distinct groups in the drawing purely for the convenience of illustration.
  • respective spool distributors 3, 4 of known types are provided, each of which can be set in three conditions corresponding respectively to movement of the respective actuator 1, 2 in a first direction, stoppage, and movement in a second direction opposite the first.
  • the inlet- outlet connections between the distributors 3, 4 and the respective actuators 1, 2 are indicated A 1' 8 1 ?? A 7 , B 7 in the drawing.
  • the settling of the spools of the distributors 3, 4 in the three possible conditions is achieved by the hydraulic piloting effected by a servocontrol valve unit, generally indicated 5, including a series of lever and pedal controls which can be put manually into different positions corresponding to the three conditions of the distributors 3, 4.
  • the outlet-inlet connections between the servocontrols 5 and the respective distributors 3, 4 are indicated a 1' b 1 .... a 7 , b 7 .
  • the pump 6 has a known type of "load sensing" control which employs a control circuit 8 with selector ball valves which make use of the greater of the pressure signals from the distributors 3, 4 in operation.
  • Each of the distributors 3, 4 also has a respective associated compensator 9 constituted, in known manner, by a normally-open, two-way directional control valve which has one side connected to the respective working member 1, 2 downstream of the respective distributor 3, 4 and the opposite side connected to the inlet of the respective distributor 3, 4.
  • the compensator devices 9 have the well-known function of keeping the difference between the pressure supplied by the pump 6 and that of the working members 1, 2 substantially constant in use, in order to ensure simultaneity of the various possible working movements of the machine independently of the loads controlled.
  • the hydraulic servocontrol devices 5 are supplied by the pump 7 under the control of a maximum pressure valve 11.
  • the maximum pressure valve 11 has an associated depressurising valve (vent valve), indicated 10, the function of which is to prevent the hydraulic circuit becoming saturated.
  • the valve 10 is constituted by an automatically-piloted, two-way control valve having one side sensitive to the pressure supplied by the pump 6 and the opposite side sensitive to the pressure in the circuit 8, that is, to the greatest of the pressures of the working members 1, 2.
  • vent valve 10 allows the maximum pilot pressure of the distributors 3, 4 to be reduced as a result of the opening of the maximum pressure valve 11 as soon as the difference between the pressure delivered by the pump 6 and the pressure of the working members 1, 2 plus the elastic load acting on the valve 10 in the same sense as the pressure of the working members 1, 2 tends to fall, that is, when the circuit tends to become saturated.
  • the reduction in the pilot pressure involves a reduction in the delivery taken up and hence ensures the simultaneity of the various movements of the working members 1 and 2 in every case.
  • FIG. 2 illustrates a circuit similar to that described above and therefore only the differences will be explained in detail, the same reference numerals being used for parts identical or similar to those of Figure 1.
  • the circuit differs from that described above solely in that the servocontrol devices 5 are supplied by the same pump 6 through a pressure reduction valve 12.
  • the vent valve 10 acts on the pressure reduction valve 12, with an effect entirely similar to that described above.
  • vent valve 10 could be operated voluntarily by the operator instead of automatically. This operation, which can be carried out mechanically, hydraulically, electrically or even pneumatically, must be effected so as to bring the pilot pressure of the distributors 3, 4 to a value such as to satisfy the non-saturated conditions of the circuit.
  • pilot pressure could be achieved by systems different from the vent valve 10, for example by means of a pressuring valve or by means of control systems in parallel with the existing pilot pressure control system and actuated by the reduction of the difference between the delivered pressure and that of the working members 1, 2 below a calibrated value.
  • the two-way control valve 10 sensitive on one side to the pressure of the main pump 6 and on the opposite side to the pressure of the working members 1, 2, is placed in parallel to the maximum pressure valve 11 through which the maximum pilot pressure of the distributors 3, 4 is shutted.
  • an accumulator 13 is provided on the line connecting such pump 7 and the valve 11.
  • the accumulator can have a capacity of 0.70 liter and a pre-loading pressure in the range of 13 bar.
  • a second accumulator 14 is provided for stabilizing the rate of flow controlled by the valve 10 and for making up the rate of flow requests of the servocontrol devices 5.
  • the accumulator 14 has a capacity corresponding to a half of that of accumulator 13, i.e. of 0.35 liter, and a pre-loading pressure also of about 13 bar.
  • valve 15 having the function of preventing fluid reflow towards the pump 7, and a restriction 16 for the calibration of the rate of flow towards the valve 10 are provided between valve 10 and pump 7.
  • the circuit of Figure 4 further comprises a twoways and two-positions valve 17 placed downstream the valve 10 and hydraulically piloted by means of a pressure signal of the pump 7, the function of which is that of allowing no-load maneuvers of the working member in case of stop of the heat engine of the machine.
  • an anti-stall circuit of the valve 10 having the function of avoiding that the latter intervene so as to prevent any action by the working members 1, 2 in the situation in which one of the working members (for instance one of the cylinders 1) is at the end of stroke, and thus the pressure supplied by the pump 6 and the load signal pressure are equal and same to the maximum pressure of the circuit.
  • the said anti-stall circuit comprises a pressure reduction valve 18 placed in the piloting line of the valve 10 by the working members pressure.
  • the valve 18 is calibrated so as to prevent the intervention of the valve 10 in the above mentioned conditions, and to calibrated restrictions 19, 20 are associated thereto, the function of which is that of avoiding influences by the valve 18 on the load signal.
  • the invention also provides for acting on the restriction of the delivery taken up by the working members 1, 2 rather than on the maximum pilot pressure, by operating on the compensating device 9. This possibility is illustrated in Figure 3, in which parts identical or similar to those already described above are indicated by the same reference numerals.
  • vent valve 10 acts in such a way as to effect closure of the compensators 9, so as to reduce the delivery to the working members 1, 2 in a manner proportional to the respective control areas of the distributors 3, 4, until equilibrium between the delivery supplied and that taken up is re-established.
  • vent valve 10 could be controlled voluntarily.

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  • Engineering & Computer Science (AREA)
  • General Engineering & Computer Science (AREA)
  • Mining & Mineral Resources (AREA)
  • Civil Engineering (AREA)
  • Structural Engineering (AREA)
  • Physics & Mathematics (AREA)
  • Fluid Mechanics (AREA)
  • Mechanical Engineering (AREA)
  • Fluid-Pressure Circuits (AREA)
  • Operation Control Of Excavators (AREA)
EP85830286A 1985-02-14 1985-11-20 Anti-saturation system for hydraulic control circuits for working members of earth-moving machines Expired EP0191275B1 (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
AT85830286T ATE46940T1 (de) 1985-02-14 1985-11-20 Anti-saettigungssystem fuer hydraulische steuerkreislaeufe von arbeitsgeraeten von erdbewegungsmaschinen.

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
IT8567149A IT1234937B (it) 1985-02-14 1985-02-14 Sistema antisaturazione per circuiti idraulici di comando con pompe e distributori compensati in pressione per organi di lavoro di macchine movimento terra
IT6714985 1985-02-14

Publications (2)

Publication Number Publication Date
EP0191275A1 EP0191275A1 (en) 1986-08-20
EP0191275B1 true EP0191275B1 (en) 1989-10-04

Family

ID=11299990

Family Applications (1)

Application Number Title Priority Date Filing Date
EP85830286A Expired EP0191275B1 (en) 1985-02-14 1985-11-20 Anti-saturation system for hydraulic control circuits for working members of earth-moving machines

Country Status (4)

Country Link
EP (1) EP0191275B1 (it)
AT (1) ATE46940T1 (it)
DE (1) DE3573453D1 (it)
IT (1) IT1234937B (it)

Families Citing this family (13)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE3546336A1 (de) * 1985-12-30 1987-07-02 Rexroth Mannesmann Gmbh Steueranordnung fuer mindestens zwei von mindestens einer pumpe gespeiste hydraulische verbraucher
IT1187892B (it) * 1986-02-04 1987-12-23 Chs Vickers Spa Circuito idraulico di comando per organi di lavoro di macchine movimento terra con frenatura centralizzata degli attuatori
IT1195178B (it) * 1986-09-24 1988-10-12 Chs Vickers Spa Sistema di recupero di portata per circuiti idraulici con pompe e di stributori compensati in pressione per organi di lavoro di macchine movimento terra
IT1208866B (it) * 1987-04-14 1989-07-10 Chs Vickers Spa Circuito idraulico di comando per organi di lavoro di macchine movimento terra con circuito di sovrali mentazione
JP2582266B2 (ja) * 1987-09-29 1997-02-19 新キヤタピラー三菱株式会社 流体圧制御システム
GB2251232B (en) * 1990-09-29 1995-01-04 Samsung Heavy Ind Automatic actuating system for actuators of excavator
DK0515608T3 (da) * 1990-12-15 1995-06-12 Barmag Barmer Maschf Hydrauliksystem
JPH05504820A (ja) * 1990-12-15 1993-07-22 バルマーク　アクチエンゲゼルシヤフト 液力システム
DE4140423A1 (de) * 1991-12-07 1993-06-09 Mannesmann Rexroth Gmbh, 8770 Lohr, De Vorrichtung zur einstellung des arbeitsfluessigkeitsdruckes
FR2807118B1 (fr) * 2000-03-28 2002-07-05 Mannesmann Rexroth Sa Circuit hydraulique pour l'actionnement de recepteurs hydrauliques multiples
JP2007255506A (ja) * 2006-03-22 2007-10-04 Komatsu Ltd 建設機械の操作制御回路
CN103062144B (zh) * 2012-12-30 2015-08-12 徐工集团工程机械股份有限公司江苏徐州工程机械研究院 一种具有抗饱和功能的负载敏感多路阀
JP6698199B1 (ja) * 2019-07-24 2020-05-27 芝浦機械株式会社 局部加圧装置

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Publication number Priority date Publication date Assignee Title
US3156098A (en) * 1959-11-20 1964-11-10 Ford Motor Co Hydraulic power system
US3146593A (en) * 1960-04-18 1964-09-01 Parker Hannifin Corp Dual pump system and control valve assembly therefor
DE1484743B1 (de) * 1963-04-24 1970-09-10 Orenstein & Koppel Ag Schaltung fuer hydrostatisch betriebene Hydrogeraete
SE342871B (it) * 1967-11-24 1972-02-21 Mitsubishi Heavy Ind Ltd
FR2250908B3 (it) * 1973-11-14 1977-08-12 Massey Ferguson Services Nv
US4074529A (en) * 1977-01-04 1978-02-21 Tadeusz Budzich Load responsive system pump controls
US4343152A (en) * 1980-05-16 1982-08-10 Caterpillar Tractor Co. Load sensing porting arrangement

Also Published As

Publication number Publication date
IT1234937B (it) 1992-06-02
DE3573453D1 (en) 1989-11-09
ATE46940T1 (de) 1989-10-15
EP0191275A1 (en) 1986-08-20
IT8567149A0 (it) 1985-02-14

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