US3709257A - Electro-hydraulic servomechanism - Google Patents

Electro-hydraulic servomechanism Download PDF

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Publication number
US3709257A
US3709257A US3709257DA US3709257A US 3709257 A US3709257 A US 3709257A US 3709257D A US3709257D A US 3709257DA US 3709257 A US3709257 A US 3709257A
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US
United States
Prior art keywords
valve
stage
housing
slide
regulator
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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 - Lifetime
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English (en)
Inventor
J Faisandier
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Societe dApplications des Machines Motrices SAMM SA
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Societe dApplications des Machines Motrices SAMM SA
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Publication of US3709257A publication Critical patent/US3709257A/en
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Expired - Lifetime legal-status Critical Current

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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
    • 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
    • F15B13/04—Fluid distribution or supply devices characterised by their adaptation to the control of servomotors for use with a single servomotor
    • F15B13/042—Fluid distribution or supply devices characterised by their adaptation to the control of servomotors for use with a single servomotor operated by fluid pressure
    • F15B13/043—Fluid distribution or supply devices characterised by their adaptation to the control of servomotors for use with a single servomotor operated by fluid pressure with electrically-controlled pilot valves
    • F15B13/0435—Fluid distribution or supply devices characterised by their adaptation to the control of servomotors for use with a single servomotor operated by fluid pressure with electrically-controlled pilot valves the pilot valves being sliding valves
    • 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
    • Y10T137/86493—Multi-way valve unit
    • Y10T137/86574—Supply and exhaust
    • Y10T137/86582—Pilot-actuated
    • Y10T137/86614—Electric

Definitions

  • the first stage consists of a regulating device with a continuous leakage type output.
  • a typical first stage may comprise a calibrated leakage port which is .throttled via a butterfly valve or equivalent device operated by the electric torque motor.
  • servo-positioning of the slideof the main or second stage valve distributor has been achieved either through the use of a differential lever connected to the first stage or with the aid of powerful return springs associated with the slide of the main valve distributor.
  • springs results inmodification of the transfer function by introducing a term denoting slide position.
  • the present invention overcomes the abovediscussed and other disadvantages of the prior art by providing a novel and improved electro-hydraulic two stage servo'mechanism.
  • the first hydraulic stage comprises a device without permanent leakage and, in particular, a servo control valve employing a standard slide.
  • closed loop control is obtained solely by hydraulic means without the employment of either springs or differential levers.
  • the invention also comprises a second stage servo valve; the second distributor employing a floating slide which is operated exclusively by an applied pressure differential.
  • the two hydraulic servo valves or distributors while mechanically independent of one another, are ranged so as to be coaxial with one another.
  • the two stage hydraulic distribution device and the electrical actuator comprise two separate subassemblies. The transmission of control movements from the electric actuator to the hydraulic assembly is affected by a linkage comprising at least one horizontal shaft which is provided with suitable sealing means whereby leakage of operating fluid from the hydraulic assembly is minimized.
  • the block or casing of the hydraulic distributor section of the present invention is indicated-at 1 and the housing or block for the electrical actuator is indicated at 2.
  • the output shaft of the electric motor is connected to a sleeve 3 of the valve distributor of the first hydraulic stage via a linkage comprising members 4, 5 and 6.
  • Linkage member 6 is in turn'connected via a horizontal shaft 8 to an arm 7.
  • the arm 7 is connected by a horizontal pin 9 to distributor sleeve 3; pin 9 passing through a hole or aperture in the sleeve.
  • suitable sealing means 10 are provided about the horizontal shaft-8 where it passes through thewall of casing l.
  • the casing 2 which receives and supports the electric torque motor has been represented symbolically by'a rectangle and, in the interest of clarity, the relative positioning of the electrical and hydraulic su'bassemblies has been changed from that shown in FIG. 1.
  • the valve or distributor comprising the first hydraulic stage is indicated at 12 and the valve or distributor comprising the second hydraulic stage is indicated at 25.
  • Pressurized operating fluid from a constant pressure source, not shown, is delivered to casing 1 via passage. 14.
  • the load on the servomechanism is connected to outlet passages 15 and 16 in casing l and thus the operating fluid leaves the casing -via passages 15 and 16' when transmitted to the point of utilization.
  • Passage [7 in casing l is connected to a reservoir, not shown.
  • FIG. 2 The slides of both distributors or hydraulic stages are shown in FIG. 2 in their middle position. Oil or other operating fluid at pressure 'P will be delivered, via passage 18 and other conduits in casing 1, ma pressure relief valve 20 of any conventional type. Relief valve 20 has, of course, been illustratedschematically in FIG. 2.
  • the pressure at the outlet of relief valve 20, and upstream of a filter 2l, will be at pressure P as shown. Any fluid leaking from relief valve 20 will be returned to the reservoir via conduits 22 and 23 and passage 17.
  • the pressure P is transmitted via conduit 24 to a first end of the chamber of the second stage hydraulic distributor 25 and-thus will act on the right hand end of slide 13 of distributor 25.
  • the slides of the first and second stage hydraulic distributors are, in the disclosed preferred embodiment, arranged coaxially.
  • the slide member of first stage distributor 12 is integral with the above-discussed sleeve 3.
  • the distributor 12, which is housed in a piston 27, is a four-way distributor.
  • the input 28 to distributor 12 is in communication with the conduit 26 while a pair of return passages 29 and 30 are in communication with the reservoir via passage .17.
  • Distributor 12 also includes a passage 31 which communicates with thechamber 33 at the left hand end of piston 27.
  • the piston 27 moves in'a jacket 32 which is coaxial with the distributors 12 and 25.
  • the-piston has been shown as distinct and separate element from the slide 13 of distributor 25.
  • piston 27 and slide 13 may be integral.
  • the surface area of the left end of piston 27 is, in a preferred embodiment, equal to twice the surface area of the right hand end of the slide 13 of distributor 25.
  • a pressure P will be created in chamber 33 at the leftend of piston 27.
  • the pressure l will beone-half of the pressure P, as aresult of the inherent leakages'in the system which are necessary to permit thefre'e movement of the slides in their respective chambers.
  • the valves of these leakages are between 50 and 200 CC per'minute. This amount of leakage is, .of course, considerably below the permanent leakage allowed by the devices whose functioning depends specifically on the existence of a permanent leakage.
  • the chamber 33 is brought into communication with the pressure P, inlet and the piston 27 will move .to the right as shown in FIG. 2. Movement of piston 27 to the right entrains the slide of distributor 25 and movement of the slide results in establishment of communication between inlet passage 14 and outlet 16.
  • the slide of distributor 25 may be moved in either of two opposite directions and movements of this slide will faithfully follow the movements of the actuator with a static precision approaching 1 micron, dynamically up to 60 H,', for example, with negligible dephasing.
  • valves according to the present invention do not employ a calibrated port of small diameter and therefore are much less susceptible to the effects of impurities.
  • a protective valve with a filtering capacity of 30 microns whereas the filters in the prior art have had to have a capacity of at least l microns.
  • the valves have no elastic elements which are subject to fatigue and thus are extremely strong and reliable.
  • the main slide 13 of the present in- 5 vention faithfully follows movements of the torque 15 special expedience such as internal leakages, friction,
  • the present invention reduces the permanent or steady state consumption of operating fluid to operational leakages. Further, the present invention permits absolute separation of the electric torque motor from the distribution of the operating fluid thereby preventing any breakdown of theelectric- 25 around the magnetic parts of the electrical actuator.
  • An electro-hydraulicservomechanism comprising:
  • two-stage fluid regulator means for'controlling the pressure applied to a load, said regulator means ina first hydraulic stage including a distributor valve, said first stage,valve having a slide member; and a second hydraulic stage including a distributor valve, said second stage valve having a floating slide member and defining an inlet for a source of pressurized fluid and at least two outlets for said fluid, said second stage valveslide havinga first reaction surface of smaller area than a first surface of said first stage valve slide, said first and second stage valve slide members cooperatmeans coupling movements of said electrical actuator means to the first stage of said regulator means.
  • the slides of said first and second stage valves are coaxial.
  • valve slides are coaxial and mechanically independent.
  • a two-stage hydraulic distributor device comprising:
  • valve housing said housing defining a bore, said housing being provided with an inlet port through which pressurized fluid may be delivered to said bore and an exhaust port, said housing further being provided with at least a pair of outlet ports adapted for connection to a fluid utilizing load;
  • said power distribution valve means disposed in said housing bore, said power distribution valve means including a longitudinally movablefloating power valve member for controlling distribution of fluid between said inlet port and respective of said outlet ports;
  • control circuit including:
  • floating piston means disposed in said valve housing bore, said floating piston means being provided with a bore and being disposed in pushing relationship with said floating power valve member in at least one direction of movement; pilot valve means disposed at least in part in said floating piston means bore, said pilot valve means including a longitudinally movable valve member, said pilot valve means controlling the application of control pressure to a first end of said floating piston means; and means connected to said pilot valve means and responsive to an input signal for positioning said pilot valve movable member. 7. The apparatus of claim 6 wherein said floating powervalve member is integral with said floating piston means.
  • said distribution device further comprises:
  • valve members and piston are coaxial with one another.

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  • Engineering & Computer Science (AREA)
  • Physics & Mathematics (AREA)
  • Fluid Mechanics (AREA)
  • Mechanical Engineering (AREA)
  • General Engineering & Computer Science (AREA)
  • Servomotors (AREA)
  • Fluid-Pressure Circuits (AREA)
US3709257D 1969-11-15 1970-09-23 Electro-hydraulic servomechanism Expired - Lifetime US3709257A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
FR6939403A FR2067780A5 (ko) 1969-11-15 1969-11-15

Publications (1)

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US3709257A true US3709257A (en) 1973-01-09

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Family Applications (1)

Application Number Title Priority Date Filing Date
US3709257D Expired - Lifetime US3709257A (en) 1969-11-15 1970-09-23 Electro-hydraulic servomechanism

Country Status (7)

Country Link
US (1) US3709257A (ko)
CH (1) CH532204A (ko)
DE (1) DE2055447A1 (ko)
ES (1) ES380366A1 (ko)
FR (1) FR2067780A5 (ko)
GB (1) GB1311738A (ko)
SE (1) SE363527B (ko)

Cited By (10)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4145956A (en) * 1977-04-25 1979-03-27 The United States Of America As Represented By The Secretary Of The Air Force Pilot operated stepping valve
US4212323A (en) * 1977-08-18 1980-07-15 Tomco, Inc. Power assist proportional remote controller
US4432033A (en) * 1982-07-01 1984-02-14 Brundage Robert W Power source for a solenoid controlled fluid pressure device
US4464977A (en) * 1980-11-12 1984-08-14 Brundage Robert W Fluid pressure device
US4545409A (en) * 1983-04-13 1985-10-08 Integral Hydraulik & Co. Electrohydraulic, two-stage, proportional displacement valve
US4553735A (en) * 1982-01-13 1985-11-19 Brundage Robert W Solenoid controlled valve
US4596271A (en) * 1980-10-02 1986-06-24 Brundage Robert W Fluid pressure device
US4951712A (en) * 1988-06-28 1990-08-28 Deere & Company Control system for a valve
US5573036A (en) * 1996-01-11 1996-11-12 Sargent Controls & Aerospace/Dover Diversified Inc. Electro-hydraulic servovalve having mechanical feedback
US5732678A (en) * 1993-06-04 1998-03-31 Man B&W Diesel A/S Slide valve and a large two-stroke internal combustion engine

Families Citing this family (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS5316183A (en) * 1976-07-28 1978-02-14 Hitachi Ltd Fluid pressure driving device
DE3124062A1 (de) * 1981-06-10 1983-01-05 Fa. J.D. Neuhaus, 5810 Witten Handsteuerventil fuer ein hydraulikaggregat
DE3135855A1 (de) * 1981-09-10 1983-03-24 Backé, Wolfgang, Prof.Dr.-Ing., 5100 Aachen Vorrichtung zur lastunabhaengigen, einem eingangssignal proportionalen hub- und winkelregelung
DD206513A3 (de) * 1981-10-26 1984-01-25 Orsta Hydraulik Veb K Stetig verstellbares 2-wege-einbauventil
DE4142883C2 (de) * 1991-12-23 1994-07-28 Orenstein & Koppel Ag Elektro-magnetische Steuereinrichtung für Ventile

Citations (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2763988A (en) * 1944-10-10 1956-09-25 Sperry Rand Corp Variable speed hydraulic transmission
US2977984A (en) * 1960-06-15 1961-04-04 United Aircraft Corp Servo solenoid valve
US2996045A (en) * 1959-07-16 1961-08-15 Honeywell Regulator Co Time modulated hydraulic servo valve
US3000363A (en) * 1959-03-31 1961-09-19 Sanders Associates Inc Two stage hydraulic servo valve
US3060969A (en) * 1960-02-24 1962-10-30 Alkon Products Corp Hydraulic valve
US3230841A (en) * 1963-08-30 1966-01-25 Ray A York Constant speed control for hydraulic motors
US3318331A (en) * 1964-01-18 1967-05-09 W E & F Control valve for high pressure hydraulic cylinders and the like
US3395617A (en) * 1965-08-30 1968-08-06 Ford Motor Co Servo motor for positioning a valve as a function of engine load

Patent Citations (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2763988A (en) * 1944-10-10 1956-09-25 Sperry Rand Corp Variable speed hydraulic transmission
US3000363A (en) * 1959-03-31 1961-09-19 Sanders Associates Inc Two stage hydraulic servo valve
US2996045A (en) * 1959-07-16 1961-08-15 Honeywell Regulator Co Time modulated hydraulic servo valve
US3060969A (en) * 1960-02-24 1962-10-30 Alkon Products Corp Hydraulic valve
US2977984A (en) * 1960-06-15 1961-04-04 United Aircraft Corp Servo solenoid valve
US3230841A (en) * 1963-08-30 1966-01-25 Ray A York Constant speed control for hydraulic motors
US3318331A (en) * 1964-01-18 1967-05-09 W E & F Control valve for high pressure hydraulic cylinders and the like
US3395617A (en) * 1965-08-30 1968-08-06 Ford Motor Co Servo motor for positioning a valve as a function of engine load

Cited By (10)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4145956A (en) * 1977-04-25 1979-03-27 The United States Of America As Represented By The Secretary Of The Air Force Pilot operated stepping valve
US4212323A (en) * 1977-08-18 1980-07-15 Tomco, Inc. Power assist proportional remote controller
US4596271A (en) * 1980-10-02 1986-06-24 Brundage Robert W Fluid pressure device
US4464977A (en) * 1980-11-12 1984-08-14 Brundage Robert W Fluid pressure device
US4553735A (en) * 1982-01-13 1985-11-19 Brundage Robert W Solenoid controlled valve
US4432033A (en) * 1982-07-01 1984-02-14 Brundage Robert W Power source for a solenoid controlled fluid pressure device
US4545409A (en) * 1983-04-13 1985-10-08 Integral Hydraulik & Co. Electrohydraulic, two-stage, proportional displacement valve
US4951712A (en) * 1988-06-28 1990-08-28 Deere & Company Control system for a valve
US5732678A (en) * 1993-06-04 1998-03-31 Man B&W Diesel A/S Slide valve and a large two-stroke internal combustion engine
US5573036A (en) * 1996-01-11 1996-11-12 Sargent Controls & Aerospace/Dover Diversified Inc. Electro-hydraulic servovalve having mechanical feedback

Also Published As

Publication number Publication date
ES380366A1 (es) 1972-12-01
SE363527B (ko) 1974-01-21
FR2067780A5 (ko) 1971-08-20
DE2055447A1 (de) 1971-05-19
GB1311738A (en) 1973-03-28
CH532204A (fr) 1972-12-31

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