US3911942A - Compensated multifunction hydraulic system - Google Patents

Compensated multifunction hydraulic system Download PDF

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Publication number
US3911942A
US3911942A US455830A US45583074A US3911942A US 3911942 A US3911942 A US 3911942A US 455830 A US455830 A US 455830A US 45583074 A US45583074 A US 45583074A US 3911942 A US3911942 A US 3911942A
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United States
Prior art keywords
line
valve
fluid
control valve
spool
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US455830A
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English (en)
Inventor
Lanson Becker
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.)
ICM ACQUISITIONS Inc A DE CORP
Hydreco Inc
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General Signal Corp
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Application filed by General Signal Corp filed Critical General Signal Corp
Priority to US455830A priority Critical patent/US3911942A/en
Priority to CA221,386A priority patent/CA1032063A/en
Priority to GB1044875A priority patent/GB1457731A/en
Priority to SE7503395A priority patent/SE402623B/xx
Priority to DE2513919A priority patent/DE2513919C2/de
Priority to FR7509729A priority patent/FR2266024B1/fr
Priority to IT48796/75A priority patent/IT1032464B/it
Priority to JP50037743A priority patent/JPS6018844B2/ja
Priority to AU79667/75A priority patent/AU7966775A/en
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Publication of US3911942A publication Critical patent/US3911942A/en
Assigned to CONTINENTAL ILLINOIS NATIONAL BANK AND TRUST COMPANY OF CHICAGO reassignment CONTINENTAL ILLINOIS NATIONAL BANK AND TRUST COMPANY OF CHICAGO SECURITY INTEREST (SEE DOCUMENT FOR DETAILS). Assignors: ICM ACQUISTIONS INC.
Assigned to CONTINENTAL ILLINOIS NATIONAL BANK AND TRUST COMPANY OF CHICAGO reassignment CONTINENTAL ILLINOIS NATIONAL BANK AND TRUST COMPANY OF CHICAGO SECURITY INTEREST (SEE DOCUMENT FOR DETAILS). Assignors: ICM ACQUISITIONS, INC., A CORP. OF DE
Assigned to HYDRECO, INC. reassignment HYDRECO, INC. CHANGE OF NAME (SEE DOCUMENT FOR DETAILS). EFFECTIVE DATE: SEPTEMBER 11, 1987 Assignors: ICM ACQUISTIONS INC.
Assigned to ICM ACQUISITIONS, INC., A DE. CORP. reassignment ICM ACQUISITIONS, INC., A DE. CORP. ASSIGNMENT OF ASSIGNORS INTEREST. Assignors: GENERAL SIGNAL CORPORATION, A NY CORP.
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    • 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
    • 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
    • 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
    • F15B11/165—Servomotor systems without provision for follow-up action; Circuits therefor with two or more servomotors with sensing of servomotor demand or load for adjusting the pump output or bypass in response to demand
    • 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
    • F15B2211/25—Pressure control functions
    • F15B2211/253—Pressure margin control, e.g. pump pressure in relation to load 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
    • F15B2211/30—Directional control
    • F15B2211/305—Directional control characterised by the type of valves
    • F15B2211/30505—Non-return valves, i.e. check 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
    • F15B2211/30—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
    • F15B2211/3144—Directional control characterised by the positions of the valve element the positions being continuously variable, e.g. as realised by proportional 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
    • F15B2211/30—Directional control
    • F15B2211/315—Directional control characterised by the connections of the valve or valves in the circuit
    • F15B2211/3157—Directional control characterised by the connections of the valve or valves in the circuit being connected to a pressure source, an output member and a return line
    • F15B2211/31576—Directional control characterised by the connections of the valve or valves in the circuit being connected to a pressure source, an output member and a return line having a single pressure source and a single output member
    • 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
    • F15B2211/35—Directional control combined with flow control
    • F15B2211/351—Flow control by regulating means in feed line, i.e. meter-in control
    • 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
    • F15B2211/40—Flow control
    • F15B2211/45—Control of bleed-off flow, e.g. control of bypass flow 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
    • F15B2211/50—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
    • F15B2211/50—Pressure control
    • F15B2211/52—Pressure control characterised by the type of actuation
    • F15B2211/528—Pressure 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
    • F15B2211/57—Control of a differential 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
    • F15B2211/60—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
    • F15B2211/6052—Load sensing circuits having valve means between output member and the load sensing circuit using check 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
    • F15B2211/60—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
    • F15B2211/6055—Load sensing circuits having valve means between output member and the load sensing circuit using pressure relief 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
    • F15B2211/7051—Linear output members
    • F15B2211/7053—Double-acting 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
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
    • Y10T—TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION
    • Y10T137/00—Fluid handling
    • Y10T137/2496—Self-proportioning or correlating systems
    • Y10T137/2559—Self-controlled branched flow systems
    • Y10T137/2574—Bypass or relief controlled by main line fluid condition
    • Y10T137/2579—Flow rate responsive
    • Y10T137/2582—Including controlling main line flow
    • Y10T137/2584—Relief or bypass closes as main opens
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
    • Y10T—TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION
    • Y10T137/00—Fluid handling
    • Y10T137/8593—Systems
    • Y10T137/87169—Supply and exhaust
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
    • Y10T—TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION
    • Y10T137/00—Fluid handling
    • Y10T137/8593—Systems
    • Y10T137/87169—Supply and exhaust
    • Y10T137/87177—With bypass
    • Y10T137/87185—Controlled by supply or exhaust valve

Definitions

  • a compensated multifunction hydraulic system for use [22] Filed; Mar, 28, 1974 with a source of hydraulic fluid includes two system valve means connected with each other and each ca- [211 Appl 455830 pable of performing a separate function.
  • One of the system valves includes a pressure compensator com- [52] US. Cl. 137/117; 91/412; 91 /446; munica ing with a control valve.
  • a first signal line up- 137/1 19; 137/596; 137/596,13 stream of said control valve moves a spool member in [51] Int. C1.
  • Means are provided in the second signal line for diverting flow in the second signal line towards the 3,7l8,l59 2/1973 Tennis l37/596.l2 Spool member in the pressure compensator o na 3,807,447 4/1974 Masuda l37/596.l3 the hydrauic fluid to flow to the other of the System valves when the control valve is in a stalled condition.
  • Pressure compensated control valves not only govern the operativeness of a fluid motor and the direction of its operation, but for a given spool position, also main tain the motor at a constant, selected speed despite variations in the load or the pressure of supply fluid.
  • the function is now in a stalled condition, as defined below, and does not actually require flow. Therefore, the pressure builds up and opens a relief valve which by-passes the flow to a reservoir. If the function operating at system relief pressure is upstream of another function operating at a lower pressure, the flow to the downstream function may be stopped.
  • stalled condition may be defined as a situation where a fluid actuator, such as a piston in a cylinder, is not able to carry out its work function, and causes pressure to build up in the line that supplies fluid to the actuator. This condition may be caused by the piston reaching the end of its stroke or by a load too heavy for the piston to overcome.
  • a fluid actuator such as a piston in a cylinder
  • a machine which looses one or more of its functions when stalling occurs is not necessarily operating at peak efficiency. Further, a sudden temporary loss of one or more functions may cause a jerkiness in the operation of the machine.
  • a compensated multifunction hydraulic system for use with a source of hydraulic fluid. It includes two system valves connected one with the other and each capable of performing a separate function. One of the system valves utilizes the necessary amount of hydrau lic fluid to perform its function in accordance with the full needs thereof. The remainder of hydraulic fluid is diverted to the other system valve. Structure is provided for permitting hydraulic fluid to flow from one system valve to the other system valve when the first system valve is in a stalled condition.
  • the one system valve may include a pressure compensator communicating with a control valve.
  • a first signal line, upstream of the control valve, positions a compensator spool to enable the fluid to flow to the other system valve when the control valve has a sufficient amount of fluid to perform its function.
  • a second signal line downstream of the control valve positions the compensator spool to deliver the necessary amount of hydraulic fluid to the control valve in accordance with the full needs thereof.
  • the improvement comprises a relief in the second signal line for diverting fluid in the second signal line towards the pressure compensator to permit fluid to flow to the other system valve when the control valve is in a stalled condition.
  • FIG. 1 is a schematic illustration of a compensated multifunction hydraulic circuit
  • FIG. 2 is a schematic illustration of a first embodiment of the present invention
  • FIG. 3 is a schematic illustration of a second embodiment of the present invention.
  • FIG. 4 is a cross-sectional view of a relief valve used in the present invention.
  • FIG. 5 is a cross-sectional view of an actuator used in the present invention.
  • FIG. 6 is a cross-sectional view of a spool-type relief valve used in the present invention.
  • a compensated multifunction hydraulic system includes a source of hydraulic fluid, such as a suitable pump 10.
  • a source of hydraulic fluid such as a suitable pump 10.
  • Two system valves 12 and 12' are connected, one with the other, and each is capable of performing of separate work function.
  • System valve 12 utilizes the necessary amount of hydraulic fluid from pump to perform its work function and diverts the remainder of hydraulic fluid to system valve 12.
  • Structure including a relief valve 16 in a second signal line 38 permit fluid to flow from system valve 12 to system valve 12 when system valve 12 is in a stalled condition.
  • FIG. 1 there is shown the compensated multifunction hydraulic system disclosed in U.S. Application Ser. No. 392,901.
  • This system controls a plurality of work functions simultaneously.
  • a pump 10 preferably of the variable delivery type such as, for example, a Dynapower Model No. 45, manufactured by the New York Air Brake Co., is illustrated.
  • the delivery of pump 10 is varied by a lever 20 which is actuated against its biasing spring 22 by movement of a piston 24 located in a cylinder 26.
  • Pump 10 is provided with a pump inlet line 28 leading to a tank T and a fluid output line 29 leading to system valves (also referred to in this disclosure as work function areas) 12 and 12.
  • work function areas 12 and 12 may perform separate and distinct functions such as, for example, function area 12 moves a bucket while function area 12' lifts a boom.
  • work functions area 12 is provided with a conventional control valve 30 and a conventional pressure compensator valve 31.
  • Work function 12 is provided with similar components, and they have been similarily numbered with corresponding primed reference characters.
  • Compensator valve 31 is connected in series with valve 31 via line 32.
  • Each of the compensator valves 31 and 31 is connected to its respective control valve 30 and 30 via lines 33 and 33 respectively.
  • the compensator valves 31 and 31 are normally biased by springs 34 and 34 to permit flow from lines 29 and 32 to reach control valves 30 and 30, through lines 33 and 33, respectively.
  • a first signal line 36 located upstream of control valve 30, allows fluid to bias a spool member (not shown) in compensator valve 31 in a direction to divert fluid to compensator valve 31' via line 32 when control valve 30 is in a neutral position (as shown in FIG. 1).
  • a load drop check valve 40 located in line 33, prevents fluid from draining out of the actuator in the event that control valve 30 is in a position to deliver fluid to the actuator when pump 10 is not functioning.
  • a second signal line 38 between control valve 30 and pressure compensator 31 allows fluid, downstream from control valve 30 to bias compensator valve 31 in the same direction as a compensator spring 34.
  • Signal line 36 and 38 sense the pressure drop across a variable orifice 42 in control valve 30 and adjust the flow from compensator valve 31 to control valve 30 so as to maintain a constant differential pressure across variable orifice 42.
  • Line 32 connects compensator valves 31 and 31' in series (that is to say, line 32 connects the areas).
  • a flow line 44, downstream of compensator valve 31 leads to structure which senses the total requirements of the system, and adjusts the output flow of pump 10 in response thereto.
  • This structure includes a restrictive orifice 46 and a control valve generally illustrated at 48.
  • Valve 48 includes a spool 50 biased by a spring 52, pilot signal ports 54 and 56, a tank port 58, a control port 60, and a pressure port 62.
  • Pilot signal port 56 allows fluid to bias spool 50 against its biasing spring 52 according to the pressure sensed via a line 64 from the upstream end of restricted orifice 46. Similarily, spool 50 is biased in the same direction as the force of spring 52 by a signal from line 66 which senses pressure at the downstream end of restricted orifice 46.
  • Pressure port 62 receives fluid from pump 10 via lines 29 and 68.
  • Control port 60 is connected to cylinder 26 via line 70 while tank port 58 is connected to tank T via a line 72.
  • Lines 74 and 74' extend from control valves 30 and 30 to tank T.
  • Valve 75 normally referred to as a pressure compensator control valve, limits the maximum pressure generated by pump 10.
  • a pressure port 76 of valve 75 receives fluid from pump 10 via lines 29 and 78.
  • the pressure in port 76 opposes a spring 80 and may move a spool 83 to allow fluid to flow to cylinder 26 of pump 10 via control valve 48 and line 70.
  • control valve 30 allows pressurized fluid from pump 10 to pass through line 29 into pressure compensator 31.
  • the spool member (not shown) in pressure compensator 31 is normally biased by spring 34 to allow all flow to pass into the control valve 30 through line 33.
  • signal lines 36 and 38 adjust compensator valve 31 to permit only the required amount of flow to perform a work function, i.e., move a piston in an actuator a desired distance, into control valve 30.
  • Flow returning from the actuator passes through line 74 and into tank T.
  • the remainder of the flow provided by pump 10 is diverted through line 32 and into downstream system valve 12'.
  • the operator may operate another work function using system valve 12 in the manner described for system valve 12.
  • pump 10 In the event that more fluid is being provided by pump 10 than necessary, it flows to orifice 46 via .line 44 and causes a pressure differential. Then, the pressure upstream of orifice 46 is sensed by line 64 and transmitted to pilot signal port 56 to bias spool 50 against spring 52. Simultaneously, the pressure downstream of orifice 46 is sensed via line 66 and transmitted to pilot signal port 54 which compensates, to the extent of the pressure drop, for the biasing caused by the higher pressure in port 56. Spool 50 is now adjusted such that fluid from pump 10 is transmitted via line 29, 68, and 70 into cylinder port 26. The flow moves piston 24 against the bias of spring 22 to adjust pump 10 so that it provides only that amount of fluid necessary to operate both work functions.
  • a problem may arise when system 12 is operating and performing a,work function, such as raising a main boom of an excavator, while valve system 12' is performing a different work function.
  • a piston, reciprocating in an actuator, used in raising the boom, may reach the end of its stroke. In this case, the actuator can no longer receive hydraulic fluid from control valve 30. At this point, system valve 12 is in a stalled condition.
  • Second signal line 138 includes a control valve line 84 connected at one end to control valve 30 and at the other end to one end of a primary line 86.
  • a compensator line 90 is connected at one end to pressure compensator 31 and at the other end to primary line 86 and to a relief valve line 92.
  • Relief valve 16 is connected to the other end of relief valve line 92 and to an end of tank line 93.
  • a flow restrictor 18 may be provided in primary line 86.
  • a secondary line 88 is shown because it is required in a schematic representation of a pressure relief valve. However, line 88 does function in a spool type relief valve as shown in FIG. 6.
  • relief valve 16 may include a housing 94 with a seat 96 in fluid communication with relief valve line 92.
  • a spring 100 biases member 98 against seat 96 in opposition to fluid pressure from relief valve line 92.
  • the ball 98 moves away from seat 96 to communicate relief valve line 92 with tank line 93 when flud pressure in line 92 increases to overcome the biasing force of spring 100.
  • the flow restrictor 18 may be used to lower the amount of fluid passing from control valve line 84 to tank T. In this way, pump 10 is not required to supply as much fluid as otherwise needed and therefore pump 10 operates more efficiently and at a lower cost.
  • the restrictor 18 may be of any required size such as, for example, 0.060 inches which passes approximately 1 gallon per minute at a pressure differential across flow restriction 18 of 100 psi.
  • a second embodiment of the present invention is similar to the first embodiment except for details of second signal line 238.
  • the second embodiment includes a relief valve 16 in second signal line 238 for diverting fluid in second signal line 238 towards pressure compensator 31. Hydraulic fluid can then flow from system valve 12 to system valve 12' when valve 12 is in a stalled condition.
  • Second signal line 238 includes a control valve line 104 connected at one end to control valve 30 and at the other end to a relief valve line 106 and to one end of a check line 108.
  • a compensator line 110 is connected at one end to pressure compensator 31 and at the other end to control valve line 104.
  • a relief valve 16 is connected to the other end of relief valve line 106 and to one end of an actuator line 112.
  • An actuator 116 is connected to the other end of actuator line 112.
  • Check line 108 includes a check valve 118 for permitting fluid to flow from actuator line 112 to control valve line 104.
  • a secondary line 114 is shown because it is required in a schematic representation of a pressure relief valve. However, line 114 does function in a spool type relief valve of the type shown in FIG. 6.
  • a cylinder 120 receives fluid from actuator line 112. This fluid causes piston 122 to reciprocate in cylinder 120. Since piston 122 is connected to the spool in compensator 31, it forces the spool against compensator spring 34.
  • check valve 118 To understand the importance of check valve 118, assume that piston 122 in actuator 116 has moved toward spring 34. When the work function associated with system valve 12 is resumed, the spool in compensator valve 31 must move toward the actuator 116. However, no fluid can pass through actuator line 112 since relief valve 16 is in a closed position. Therefore, check valve 118 which permits flow to control valve line 104 permits the actuator to drain and thus allow pressure compensator 31 to move in the direction of the force of spring 34.
  • the relief valve 16, as shown in FIG. 4 is only an example of many commercial devices that may be used in the present invention.
  • a spool valve such as the one shown in FIG. 6, may be used.
  • Spool valve 124 includes a cylinder 126.
  • a spool 128 with two lands 129 is slidably received within cylinder 126.
  • Spool spring 130 in one end of cylinder 126, biases spool 128 so that a fluid line 132 is connected to spool cylinder 126 so as to always be in communication with annular space 131 between lands 129.
  • Line 134 is connected to the end of cylinder 126 containing spring 130.
  • a pressure line 136 is connected to the other end of cylinder 126 so that fluid from line 136 biases spool 128 against spring 130 so as to permit fluid to flow from line 132 to line 134 via space 131.
  • line 132 is considered a relief valve line
  • line 136 is considered a secondary line
  • line 134 is a drain to tank.
  • variable delivery pump a fixed displacement pump can easily by used in conjunction with the present invention.
  • description has been limited to two work function areas for convenience only. It should be understood that an unlimited number of areas may be provided in series. The limitation on the number of work function areas is governed primarily by the practical limits placed upon pump 10 in that it usually provides the total requirements of all the functions being performed. Further, in some cases a work function area may consist of a conventional control valve without pressure compensation.
  • a compensated multifunction hydraulic system for use with a source of hydraulic fluid including two system valve means being connected one with the other and each capable of performing a separate function, one of said system valve means including a pressure compensator communicating with a control valve, a first signal line means upstream of said control valve for moving a compensator spool in a first direction in said pressure compensator to enable said fluid to flow to the other of said system valve means, a second signal line means downstream of said control valve for moving said compensator spool in a second direction to deliver the necessary amount of hydraulic fluid to said control valve in accordance with the full needs thereof, the improvement comprising:
  • relief means in said second signal line means for directing fluid from said second signal line means toward said pressure compensator whereby said compensator spool moves in said first direction when said control valve is in a stalled condition.
  • said second signal line means includes a control valve line connected at one end to said control valve and at the other end to one end ofa relief valve line and to one end of a check line, a compensator line connected at one end to said pressure compensator and at the other end to said control valve line, said relief means connected to the other end of said relief valve line and to one end of an actuator line, and an actuator connected to the other end of said actuator line for engaging said compensator spool so that fluid pressure in said relief valve line actuates said relief means to permit fluid from said control valve line to flow from said relief valve line through said relief means to said actuator line to move said actuator and thereby move said c r sator spool.
  • said actuator comprises a cylinder for receiving fluid from said actuator line, an actuator piston in said cylinder engaging said pressure compensator wherein fluid from said actuator line reciprocates said actuator piston to move said compensator spool.
  • check line includes a check valve for permitting fluid to flow from said actuator line to said control valve line when said actuator is drained.
  • said relief means comprises a relief valve which includes a housing with a seat in fluid communication with said relief valve line, a moveable member engaging said seat, spring means for biasing said moveable member against said seat in opposition to fluid pressure in said relief valve line, whereby said moveable member moves away from said seat when fluid pressure in said relief valve line increases to a predetermined amount because of the stalled condition of said control valve.
  • said relief means comprises a spool valve including a cylinder, a spool with two lands, a spool spring in one end of said spool cylinder, one end of a secondary line connected to said check line and the other end to said spool valve, said relief valve line connected to said spool cylinder so as to be in communication with an an nular space between said two lands, said actuator line connected to said one end of said spool cylinder, said secondary line connected to an other end of said spool cylinder wherein fluid from said secondary line biases said spool valve against said spool spring to permit fluid from said control valve line to flow through said relief valve line, through said spool valve and to said actuator line when said control valve is in the stalled condition.
  • said other of said system valve means includes a second pressure compensator and a second control valve.
  • said second signal line means comprises an actuator which includes a cylinder for receiving diverted fluid from said relief means, an actuator piston reciprocating in said cylinder and moving said compensator spool to enable said hydraulic fluid to flow to the other of said system valve means when said control valve is in a stalled condition.

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  • Engineering & Computer Science (AREA)
  • General Engineering & Computer Science (AREA)
  • Physics & Mathematics (AREA)
  • Fluid Mechanics (AREA)
  • Mechanical Engineering (AREA)
  • Mining & Mineral Resources (AREA)
  • Civil Engineering (AREA)
  • Structural Engineering (AREA)
  • Fluid-Pressure Circuits (AREA)
  • Servomotors (AREA)
US455830A 1974-03-28 1974-03-28 Compensated multifunction hydraulic system Expired - Lifetime US3911942A (en)

Priority Applications (9)

Application Number Priority Date Filing Date Title
US455830A US3911942A (en) 1974-03-28 1974-03-28 Compensated multifunction hydraulic system
CA221,386A CA1032063A (en) 1974-03-28 1975-03-06 Compensated multifunction hydraulic system
GB1044875A GB1457731A (en) 1974-03-28 1975-03-13 Compensated multifunction hydraulic system
SE7503395A SE402623B (sv) 1974-03-28 1975-03-24 Kompenserat hydrauliskt flerfunktionssystem
FR7509729A FR2266024B1 (da) 1974-03-28 1975-03-27
IT48796/75A IT1032464B (it) 1974-03-28 1975-03-27 Perfezionamento nei sistemi idraulici con pompa a portata variabile
DE2513919A DE2513919C2 (de) 1974-03-28 1975-03-27 Druckkompensierter Hydraulikkreis
JP50037743A JPS6018844B2 (ja) 1974-03-28 1975-03-28 補償型の多機能液圧装置
AU79667/75A AU7966775A (en) 1974-03-28 1975-04-01 Compensated multifunction hydraulic system

Applications Claiming Priority (1)

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US455830A US3911942A (en) 1974-03-28 1974-03-28 Compensated multifunction hydraulic system

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US3911942A true US3911942A (en) 1975-10-14

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US455830A Expired - Lifetime US3911942A (en) 1974-03-28 1974-03-28 Compensated multifunction hydraulic system

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US (1) US3911942A (da)
JP (1) JPS6018844B2 (da)
CA (1) CA1032063A (da)
DE (1) DE2513919C2 (da)
FR (1) FR2266024B1 (da)
GB (1) GB1457731A (da)
IT (1) IT1032464B (da)
SE (1) SE402623B (da)

Cited By (17)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4037620A (en) * 1976-04-23 1977-07-26 Eaton Corporation Controller for fluid pressure operated devices
DE2728118A1 (de) * 1976-06-23 1978-01-05 Eaton Corp Steuergeraet fuer druckmittelbetaetigbare vorrichtungen
US4129987A (en) * 1977-10-17 1978-12-19 Gresen Manufacturing Company Hydraulic control system
US4142842A (en) * 1974-09-09 1979-03-06 Caterpillar Tractor Co. Dual source hydraulic steering system
US4215720A (en) * 1978-10-02 1980-08-05 General Signal Corporation Fluid control valve system
EP0020465A1 (en) * 1978-10-12 1981-01-07 Caterpillar Tractor Co PRIORITY HYDRAULIC CIRCUIT WITH CONTROLLED REQUEST.
US4282898A (en) * 1979-11-29 1981-08-11 Caterpillar Tractor Co. Flow metering valve with operator selectable boosted flow
US4453451A (en) * 1980-11-10 1984-06-12 Fiatallis North America, Inc. Hydraulic steering system with automatic emergency pump flow control
US4545407A (en) * 1984-02-29 1985-10-08 United Technologies Corporation Jam compensating control valve
US4905933A (en) * 1987-08-07 1990-03-06 Teijin Seiki Company Limited Control apparatus of control surface of aircraft
US5050483A (en) * 1989-08-10 1991-09-24 Kabushiki Kaisha Kobe Seiko Sho Flow control device
US5062350A (en) * 1989-03-22 1991-11-05 Hitachi Construction Machinery Co., Ltd. Hydraulic drive system for civil engineering and construction machine
US5146747A (en) * 1989-08-16 1992-09-15 Hitachi Construction Machinery Co., Ltd. Valve apparatus and hydraulic circuit system
EP0936179A1 (de) * 1998-02-13 1999-08-18 HEILMEIER & WEINLEIN Fabrik für Oel-Hydraulik GmbH & Co. KG Staplersteuerung
EP1046610A2 (en) * 1999-04-20 2000-10-25 BT Industries Aktiebolag Device and method for movement of a load carrier at an industrial truck
US20100307621A1 (en) * 2007-11-14 2010-12-09 Rueb Winfried Hydraulic valve device
WO2012166225A2 (en) * 2011-02-28 2012-12-06 Caterpillar Inc. Hydraulic control system having cylinder stall strategy

Families Citing this family (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3982469A (en) * 1976-01-23 1976-09-28 Caterpillar Tractor Co. Apparatus for controlling work element operating pressures in a fluid system
US3987623A (en) * 1976-01-23 1976-10-26 Caterpillar Tractor Co. Controlled priority fluid system of a crawler type vehicle
DE3710699C1 (de) * 1987-03-31 1988-08-18 Heilmeier & Weinlein Hydraulische Steuervorrichtung fuer eine Verbrauchergruppe

Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3718159A (en) * 1971-01-20 1973-02-27 Hydraulic Industries Control valve
US3807447A (en) * 1972-02-24 1974-04-30 Daikin Ind Ltd Fluid controlling apparatus

Family Cites Families (3)

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Publication number Priority date Publication date Assignee Title
US2892312A (en) * 1958-01-27 1959-06-30 Deere & Co Demand compensated hydraulic system
US3602104A (en) * 1969-07-08 1971-08-31 Eaton Yale & Towne Pressure-compensated flow control
US3782404A (en) * 1972-06-14 1974-01-01 Commercial Shearing Adjustable, metered, directional flow control arrangements

Patent Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3718159A (en) * 1971-01-20 1973-02-27 Hydraulic Industries Control valve
US3807447A (en) * 1972-02-24 1974-04-30 Daikin Ind Ltd Fluid controlling apparatus

Cited By (25)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4142842A (en) * 1974-09-09 1979-03-06 Caterpillar Tractor Co. Dual source hydraulic steering system
US4037620A (en) * 1976-04-23 1977-07-26 Eaton Corporation Controller for fluid pressure operated devices
DE2728118A1 (de) * 1976-06-23 1978-01-05 Eaton Corp Steuergeraet fuer druckmittelbetaetigbare vorrichtungen
FR2356192A2 (fr) * 1976-06-23 1978-01-20 Eaton Corp Dispositif de commande pour appareils actionnes par pression de fluide
US4129987A (en) * 1977-10-17 1978-12-19 Gresen Manufacturing Company Hydraulic control system
US4215720A (en) * 1978-10-02 1980-08-05 General Signal Corporation Fluid control valve system
EP0020465A1 (en) * 1978-10-12 1981-01-07 Caterpillar Tractor Co PRIORITY HYDRAULIC CIRCUIT WITH CONTROLLED REQUEST.
EP0020465A4 (en) * 1978-10-12 1981-02-04 Caterpillar Tractor Co PRIORITY HYDRAULIC CIRCUIT WITH CONTROLLED REQUEST.
US4282898A (en) * 1979-11-29 1981-08-11 Caterpillar Tractor Co. Flow metering valve with operator selectable boosted flow
US4453451A (en) * 1980-11-10 1984-06-12 Fiatallis North America, Inc. Hydraulic steering system with automatic emergency pump flow control
US4545407A (en) * 1984-02-29 1985-10-08 United Technologies Corporation Jam compensating control valve
US4905933A (en) * 1987-08-07 1990-03-06 Teijin Seiki Company Limited Control apparatus of control surface of aircraft
US5062350A (en) * 1989-03-22 1991-11-05 Hitachi Construction Machinery Co., Ltd. Hydraulic drive system for civil engineering and construction machine
US5050483A (en) * 1989-08-10 1991-09-24 Kabushiki Kaisha Kobe Seiko Sho Flow control device
US5146747A (en) * 1989-08-16 1992-09-15 Hitachi Construction Machinery Co., Ltd. Valve apparatus and hydraulic circuit system
EP0936179A1 (de) * 1998-02-13 1999-08-18 HEILMEIER & WEINLEIN Fabrik für Oel-Hydraulik GmbH & Co. KG Staplersteuerung
EP1046610A2 (en) * 1999-04-20 2000-10-25 BT Industries Aktiebolag Device and method for movement of a load carrier at an industrial truck
EP1046610A3 (en) * 1999-04-20 2005-11-30 BT Industries Aktiebolag Device and method for movement of a load carrier at an industrial truck
US20100307621A1 (en) * 2007-11-14 2010-12-09 Rueb Winfried Hydraulic valve device
US8479769B2 (en) * 2007-11-14 2013-07-09 Hydac Filtertechnik Gmbh Hydraulic valve device
WO2012166225A2 (en) * 2011-02-28 2012-12-06 Caterpillar Inc. Hydraulic control system having cylinder stall strategy
WO2012166225A3 (en) * 2011-02-28 2013-01-24 Caterpillar Inc. Hydraulic control system having cylinder stall strategy
CN103403364A (zh) * 2011-02-28 2013-11-20 卡特彼勒公司 具有缸失速策略的液压控制系统
US8813486B2 (en) 2011-02-28 2014-08-26 Caterpillar Inc. Hydraulic control system having cylinder stall strategy
CN103403364B (zh) * 2011-02-28 2016-01-06 卡特彼勒公司 具有缸失速策略的液压控制系统

Also Published As

Publication number Publication date
FR2266024A1 (da) 1975-10-24
JPS6018844B2 (ja) 1985-05-13
GB1457731A (en) 1976-12-08
FR2266024B1 (da) 1980-09-12
DE2513919C2 (de) 1982-12-30
CA1032063A (en) 1978-05-30
SE7503395L (da) 1975-09-29
IT1032464B (it) 1979-05-30
JPS50130981A (da) 1975-10-16
SE402623B (sv) 1978-07-10
DE2513919A1 (de) 1975-10-09

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