EP0160265B1 - Hydraulisches Steuersystem - Google Patents

Hydraulisches Steuersystem Download PDF

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Publication number
EP0160265B1
EP0160265B1 EP85104920A EP85104920A EP0160265B1 EP 0160265 B1 EP0160265 B1 EP 0160265B1 EP 85104920 A EP85104920 A EP 85104920A EP 85104920 A EP85104920 A EP 85104920A EP 0160265 B1 EP0160265 B1 EP 0160265B1
Authority
EP
European Patent Office
Prior art keywords
meter
valve
pressure
out valve
actuator
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
EP85104920A
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English (en)
French (fr)
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EP0160265A3 (en
EP0160265A2 (de
Inventor
Vinod Kumar Nanda
Henry Delano Taylor
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 Inc
Original Assignee
Vickers Inc
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Filing date
Publication date
Application filed by Vickers Inc filed Critical Vickers Inc
Publication of EP0160265A2 publication Critical patent/EP0160265A2/de
Publication of EP0160265A3 publication Critical patent/EP0160265A3/en
Application granted granted Critical
Publication of EP0160265B1 publication Critical patent/EP0160265B1/de
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
    • 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

Definitions

  • This invention relates to a hydraulic control system according to the preamble of claim 1.
  • Such hydraulic systems are found, for example, on mobile equipment, such as excavators and cranes, and are used to control an actuator, such as a hydraulic cylinder or hydraulic motor.
  • the actuator normally has two openings or ports to be used alternately as inlet or outlet.
  • the valves comprise a hydraulically operated meter-in-valve, a pair of load drop check valves, a pair of hydraulically operated, normally closed meter-out valves, a pair of load pressure responsive valves, and a pair of anti-cavitation valves.
  • the meter-in valve functions to direct fluid flow to one or the other of the actuator ports.
  • Each a meter-out valve is associated with a pertinent actuator port and functions as a variable orifice metering fluid between the appropriate actuator port and a return line to tank.
  • Each load pressure responsive valve acts on the respective meter-out valve to which it is associated and that in response to load pressure to enable the meter-out valves to also provide pressure relief protection.
  • the anti-cavitation valves are associated with each of the actuator ports and are adapted to open the appropriate port to the return line.
  • the valve body is directly mounted to the actuator port manifold and is supplied by one full flow high pressure line, a pair of pilot pressure lines, and a load sensing line.
  • the operation of the valves is controlled through the pilot lines from a manually operated hydraulic remote control valve which provides high or low pilot pressure.
  • the meter-in valve assumes a centered or neutral position with the check valves, the meter-out valves, the pressure responsive valves and the anti-cavitation valves all in closed position so that the valve system prevents uncontrolled lowering of loads, and in the case of overrunning loads, prevents fluid flow from the high pressure fluid source to the actuator even in the . event of a ruptured line. Due to the normally closed meter-out valves, such a hydraulic control system does not lend itself to free float, swing or coast the actuator.
  • Fig. 1 is a schematic drawing of a hydraulic control system for an actuator having two openings
  • Fig. 2 is a sectional view of an embodiment of a modified hydraulic control system.
  • the hydraulic control system embodying the invention comprises an actuator 20, herein shown as a linear hydraulic cylinder, having openings A, B and an output shaft 21 that is moved in opposite directions by hydraulic fluid supplied from a variable displacement pump 22 which has load sensing control 79 through 82 as is fully described in EP 85,962 A3.
  • the hydraulic control system further includes a manually operated controller 23 that directs high or low pilot pressure through pilot port C1 or C2 to a valve system 24 for controlling the direction of movement of the actuator 20.
  • Fluid from the pump 22 is directed through supply line 25 and port P to intake passage 26 and to a meter-in valve 27 that functions to direct and control the flow of hydraulic fluid to one or the other openings A, B through working lines having sections 32 and 33 which are connected to the openings A, B through load drop check valves 37 and 38, respectively.
  • the load drop check valves 37, 38 are formed as spring loaded poppet valves and separate the upstream section 32 or 33 from the downstream opening A or B of the working lines. Further spring-loaded anti-cavitation valves 39, 40 are opened when pressure in a return passage 36 to tank is higher than in the downstream opening A or B.
  • pilot ports C1 and C2 are extended by pilot control lines 28, 30 and pilot control lines 29, 31, respectively, to the opposed ends of the meter-in valve 27.
  • hydraulic fluid passes through working lines 32, A or 33, B to one or the other end of the actuator 20.
  • the hydraulic control system further includes exhaust means including normally closed meter-out valves 34d, 35d, each positioned between the openings A or B and the return passage 36.
  • the meter-out valves 34d, 35d control the return flow or fluid to tank.
  • the meter-out valves 34d, 35d can be designed as second stage of a relief valve, see Figure 2.
  • spring loaded poppet valves 41, 42 ( Figure 2) acting as pilot valves are associated with each valve 34d, 35d.
  • the system also includes a back pressure valve 44 connected to the tank port T and associated with the return passage 36.
  • Back pressure valve 44 functions to minimize cavitation when an overruning or a lowering load tends to drive the actuator down.
  • a charge pump relief valve 45 is provided to take excess flow above the inlet requirements of the pump 22 and apply it to the back pressure valve 44 to augment the fluid available to the actuator.
  • Meter-in valve 27 comprises a bore in which a spool is positioned, at low pilot pressure ("normally") the spool is maintained in a neutral position by springs and blocks the flow from the supply line 26 to the line sections 32, 33.
  • low pilot pressure normally
  • the spool moves until a force balance exists among the high pilot pressure, the spring load and the flow forces.
  • the direction of movement determines which of the line sections 32, 33 is provided with fluid under pressure from intake passage 26.
  • the single meter-in valve 27 may be replaced by two meter-in valves as shown in DE-A-3,011,088.
  • the meter-out valves 34d, 35d are of the poppet type and have control chambers 63a and 63b, respectively, which are connected to the openings A and B through orifices 62a and 62b, respectively, and can be vented by retracting a stem 65a and 65b, respectively, each is connected to a piston 67a and 67b, respectively.
  • pilot pressure is admitted through control line 28, piston 67a and stem 65a are moved and control chamber 63a vented so that pressure in the opening A opens meter-out valve 34d. Similar operation is carried out with pilot pressure in control line 29 and meter-out valve 35d.
  • the exhaust valves 34d, 35d are also controlled by the poppet valves 41, 42, which are acted upon, on one side, by load pressure in the opening A or B, and, on the other side, by the same pressure, yet delayed.
  • a restricted passage 72 through load drop check valve 37 leads to an accumulator volume 72a and to a spring cavity 41 a of the poppet valve 41.
  • poppet valve 41 is sensitive for sudden pressure rise in working line A and lowers the respond pressure (An fabricatwert) of the meter-out valve 34d for a short time. This is accomplished by venting the control chamber 63a or meter-out valve 34d to low pressure in return passage 36 via a passage 73a.
  • poppet valve 42 including another spring cavity 42b, accumulator volume 72b, orifice 62b and passage 73b.
  • poppet valve 41 or 42 returns in its normal position shutting off the passage 73a or 73b, so that control pressure in valve 34d or 35d is again built up.
  • restricted passages 27a, 27b in the valve spool connect pilot line 30 to working line section 32 and pilot line 31 to working line section 33.
  • a drain passage 90 is provided to connect upstream working line section 32 to the accumulator volume 72a and therethrough to the spring cavity 41 a of the poppet valve 41. So low pilot pressure is extended to spring cavity 41a, i.e. the pressure holding the poppet valve 41 closed is reduced and allowing to open valve 41, even if a relatively low load pressure (approximately 200 psi) is developed in downstream opening A. Control pressure in space 63a is vented through passage 73a, and the pressure in the downstream opening A is allowed to open the meter-out valve 34d to the return passage 36.
  • valve system 24 provides for a float or coast characteristic of the actuator movement in one direction.
  • a similar passage (92 in Fig. 1) between the upstream working line section 33 and the accumulator volume 72b is added which reduces the control pressure of the meter-out valve 35d in the neutral position of the meter-in valve 27.
  • one or the other or both passages 90, 92 are used to lower control pressure for the valves 34d or 35d which are thus allowed to open in response to low load pressures in the opening A or B.
  • the meter-out valve 34d or 35d in the embodiment of Figure 1 is controlled by a single pilot source (the controller 33)
  • the meter-out valve 34d or 35 in Figure 2 is controlled by so as to speak "two pilot sources", firstly the controller 23 and secondly the load pressure in opening A or B.

Claims (5)

1. Hydraulisches Steuersystem mit folgenden Merkmalen:
eine Pumpe (22) zur Zuführung von Druckfluid,
eine hydraulische Betätigungseinrichtung (20) mit einem bewegbaren Element (21) und mindestens einem Anschluß (A), der abwechselnd als Einlaß oder Auslaß des Fluids dienen kann;
ein Leitungssystem (26,32,36) dient zur Verbindung der Pumpe (22) mit dem Anschluß (A) der Betätigungseinrichtung und mit einem Tank und weist eine Arbeitsleitung (32, A) und eine Rücklaufleitung (36) auf;
eine Zufuhrbemessungsventileinrichtung (27) ist in dem Leitungssystem so angeordnet, daß dem Anschluß (A) der Betätigungseinrichtung über die Arbeitsleitung (32, A) zuzuführendes Fluid entweder abgesperrt oder hindurchgelassen wird;
eine Auslaßeinrichtung weist ein (erstes) Auslaßbemessungsventil (34d) auf, welches zwischen der Arbeitsleitung (A) und der Rücklaufleitung (36) angeordnet ist und entweder den Rückfluß des Fluids zum Tank zuläßt oder diesen Strom absperrt;
eine Pilotsteuereinrichtung (23) ist zur Zuführung von Fluid bei hohem oder niedrigem Pilotdruck zu der Zufuhrbemessungsventiieinrichtung (27) und dem Auslaßbemessungsventil (34d) vorgesehen, um die Stellung dieser Ventile zu bestimmen;
das Zufuhrbemessungsventil (27) ist bei niedrigem Pilotdruck in seiner geschlossenen Stellung und bei hohem Pilotdruck in der geöffneten Stellung;
das Auslaßbemessungsventil (34d) besitzt eine Steuerkammer (63a), welche über eine Drosselverbindung (62a) mit Lastdruck versorgt wird und über ein Vorsteuerventil (65a, 67a) druckentlastet werden kann, welches durch die Pilotsteuereinrichtung (23) gesteuert wird, das Auslaßbemessungsventil (34d) ist so ausgebildet, daß der Lastdruck auf das Auslaßbemessungsventil (34d) in Öffnungwirkung gegen die Schließkraft wirkt, die durch den Druck in der Steuerkammer (63a) ausgeübt wird, dadurch gekennzeichnet,
daß ein (erster) Abflußkanal (90, 27a) zur Verringerung des Druckes in der Steuerkammer (63a) des (ersten) Auslaßbemessungsventils (34d) vorgesehen ist, wenn das Zufuhrbemessungsventil (27) in seiner neutralen Stellung ist, wobei dem Auslaßbemessungsventil (34d) ermöglicht wird, zu öffnen.
2. Hydraulisches Steuersystem nach Anspruch 1, worin die Betätigungseinrichtung (20) doppeltwirkend ist und zwei Betätigungsanschlüsse (A, B), das Leitungssystem zwei Arbeitsleitungen (32a; 33b) und die Auslaßeinrichtung ein zweites Auslaßbemessungsventil (35d) aufweisen, dadurch gekennzeichnet, daß ein zweiter Abflußkanal (92, 27b) zur Erniedrigung des Drucks in der Steuerkammer (63b) des zweiten Auslaßbemessungsventils (35d) vorgesehen ist, wenn das Zufuhrbemessungsventil (27) in seiner neutralen Stellung ist, wobei dem zweiten Auslaßbemessungsventil (35d) ermöglicht wird, zu öffnen.
3. Hydraulisches Steuersystem nach Anspruch 1 oder 2, worin jede Arbeitsleitung (32, A; 33, B) ein Lastabfall-Rückschlagventil (37, 38) aufweist, welches in der neutralen Stellung der Zufuhrbemessungsventileinrichtung (27) einen stromaufseitigen Abschnitt (32, 33) der Arbeitsleitung von dem Anschluß (A, B) als dem stromabseitigen Abschnitt trennt, worin mindestens ein normalerweise geschlossenes, federvorgespanntes Sitzventil (41, 42) mit einer Federkammer (41a, 42b) durch Lastdruck an dem betreffenden Betätigeranschluß (A, B) in Öffnungsrichtung und durch Druck in der Federkammer (41a, 42b) in Schließrichtung gedrängt wird und einem betreffenden Auslaßbemessungsventil (34d, 35d) zugeordnet ist, um den Druck in der Steuerkammer (63a, 63b) des Auslaßbemessungsventils (34d, 35d) zu steuern und worin der Abflußkanal (90, 27a, 92, 27b) einen ersten Abschnitt (90, 92) aufweist, welcher den stromaufseitigen Abschnitt (32; 33) mit der Federkammer (41a; 42b) des Sitzventils (41; 42) verbindet.
4. Hydraulisches Steuersystem nach Anspruch 3, worin die Federkammer (41a; 42b) des Sitzventils (41; 42) mit einem Akkumulatorvolumen (72a; 72b) verbunden ist, welches mit dem ersten Abschnitt (90; 92) des Abflußkanals (90, 27a; 92; 27b) verbunden ist.
5. Hydraulisches Steuersystem nach Ansprüchen 3 oder 4, worin die Zufuhrbemessungsventileinrichtung (27), das Auslaßbemessungsventil oder die Auslaßbemessungsventile (32, A; 33, B) und der Abflußkanal oder die Abflußkanäle (90, 27a; 92, 27b) in einem Ventilgehäuse (24) untergebracht sind.
EP85104920A 1984-04-30 1985-04-23 Hydraulisches Steuersystem Expired EP0160265B1 (de)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
US60560784A 1984-04-30 1984-04-30
US605607 1984-04-30

Publications (3)

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EP0160265A2 EP0160265A2 (de) 1985-11-06
EP0160265A3 EP0160265A3 (en) 1986-02-12
EP0160265B1 true EP0160265B1 (de) 1989-01-11

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EP85104920A Expired EP0160265B1 (de) 1984-04-30 1985-04-23 Hydraulisches Steuersystem

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EP (1) EP0160265B1 (de)
AU (1) AU583504B2 (de)
CA (1) CA1234529A (de)
DE (1) DE3567509D1 (de)
IN (1) IN164362B (de)

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN110667809A (zh) * 2019-09-27 2020-01-10 北京精密机电控制设备研究所 一种流量精确控制的浮力调节系统

Families Citing this family (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN104030163B (zh) * 2014-05-23 2016-06-29 武汉武桥交通装备技术有限公司 一种船用全液压起重机低能耗及低发热恒压系统
WO2017188869A1 (en) * 2016-04-28 2017-11-02 Volvo Construction Equipment Ab Hydraulic system

Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE3011088A1 (de) * 1979-03-26 1980-10-09 Sperry Corp Hydraulische antriebsschaltung
EP0085962A2 (de) * 1982-02-08 1983-08-17 Vickers Incorporated Hydraulisches Steuersystem,insbesondere für schwenkende Lasten

Family Cites Families (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2044366A (en) * 1934-11-24 1936-06-16 Pierson Gordon Green Method for separation and recovery of au, pt, pd, se, te, and as by means of mercurous salts
DE3011196A1 (de) * 1979-03-26 1980-10-09 Sperry Corp Hydraulische vielfunktion-ventilanordnung
US4201052A (en) * 1979-03-26 1980-05-06 Sperry Rand Corporation Power transmission
US4407122A (en) * 1981-05-18 1983-10-04 Vickers, Incorporated Power transmission
US4520625A (en) * 1982-03-04 1985-06-04 Kabushiki Kaisha Komatsu Seisakusho Hydraulic brake valve system

Patent Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE3011088A1 (de) * 1979-03-26 1980-10-09 Sperry Corp Hydraulische antriebsschaltung
EP0085962A2 (de) * 1982-02-08 1983-08-17 Vickers Incorporated Hydraulisches Steuersystem,insbesondere für schwenkende Lasten

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN110667809A (zh) * 2019-09-27 2020-01-10 北京精密机电控制设备研究所 一种流量精确控制的浮力调节系统

Also Published As

Publication number Publication date
DE3567509D1 (en) 1989-02-16
EP0160265A3 (en) 1986-02-12
AU4177085A (en) 1985-11-07
IN164362B (de) 1989-03-04
CA1234529A (en) 1988-03-29
EP0160265A2 (de) 1985-11-06
AU583504B2 (en) 1989-05-04

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