US3902402A - Electro-hydraulic actuator - Google Patents

Electro-hydraulic actuator Download PDF

Info

Publication number
US3902402A
US3902402A US444166A US44416674A US3902402A US 3902402 A US3902402 A US 3902402A US 444166 A US444166 A US 444166A US 44416674 A US44416674 A US 44416674A US 3902402 A US3902402 A US 3902402A
Authority
US
United States
Prior art keywords
pressure
piston
bore
piston rod
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 - Lifetime
Application number
US444166A
Other languages
English (en)
Inventor
Ronald Bernard Walters
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
Sperry Rand Ltd
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 Sperry Rand Ltd filed Critical Sperry Rand Ltd
Application granted granted Critical
Publication of US3902402A publication Critical patent/US3902402A/en
Assigned to VICKERS, INCORPORATED reassignment VICKERS, INCORPORATED ASSIGNMENT OF ASSIGNORS INTEREST. Assignors: SPERRY LIMITED
Anticipated expiration legal-status Critical
Expired - Lifetime legal-status Critical Current

Links

Images

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
    • F15B9/00—Servomotors with follow-up action, e.g. obtained by feed-back control, i.e. in which the position of the actuated member conforms with that of the controlling member
    • F15B9/02—Servomotors with follow-up action, e.g. obtained by feed-back control, i.e. in which the position of the actuated member conforms with that of the controlling member with servomotors of the reciprocatable or oscillatable type
    • F15B9/03—Servomotors with follow-up action, e.g. obtained by feed-back control, i.e. in which the position of the actuated member conforms with that of the controlling member with servomotors of the reciprocatable or oscillatable type with electrical control means

Definitions

  • An actuator comprising a body having a bore, a piston in said bore and having a piston rod.
  • a system pressure gallery or passage is arranged in the body for the application of system pressure to the annular area be-,
  • a chamber is provided in the body for applying pressure to the other end of the piston.
  • the chamber communicates with the system pressure passage through a fixed orifice, and with an exhaust outlet through a variable orifice controlled by a flapper disc arranged to close the end of an outlet tube.
  • the flapper disc has on its opposite face a pressure balancing tube of the same diameter as the outlet tube and working in a bore in the piston. The pressure in this bore is equalized to the exhaust pressure and the flapper disc is controlled by the spring centered armature of a solenoid or force motor.
  • the present invention relates to electrically operated fluid actuators and it is an object of the invention to provide such an actuato of simple and reliable construction.
  • the invention is primarily applicable to electrohydraulic actuators, but can also be applied to elec' tro-pneumatic actuators.
  • An actuator comprises a piston having a piston rod. a system pressure gallery arranged'for the application of system pressure to the annular area between the piston and the piston rod, and a gallery or passage for applying pressure to the other end of the piston; the gallery communicating with'the pressure system gallery through a fixed orificesand with an exhaust outlet through avariable orifice controlled by a flapper disc arranged to close .the end of an outlet tubebthe flapper disc having on its opposite face a pressure balancing-tube of the same diameter as the outlet tube and working in a bore in the piston, the pressure in this' bore being equalized to the exhaust pressure, preferably by a passage through the flapper disc, and the flapper disc being controlled by the spring centered armature of a solenoid or force motor.
  • the outlet tube has a sharp edge at its outer diameter and the pressure balancing tube is of the same outside diameter as this edge.
  • the centering springs are set up so that in the absence of any electric current the flapper disc is positioned away from the end of the outlet tube, and the variable orifice thereby fully open.
  • a suitable current is'passed through the solenoid or force motor the flapper disc is drawn towards the outlet tube, closing the variable orifice and increasing the pressure on the piston until the hydraulic forces on it are in balance. increase in current above this point causes the piston to move outwards, and diminution causes it to be retracted.
  • the actuator- will normally be employed in an electric feed-back circuit by means of which the current to the actuator is controlled in dependence on the position of the piston'rod.
  • v I i The invention includes combinations of an actuator as abovedescribed with'such an electric feed-back circuit. I W w The invention will be further described by way of example with referenceto the accompanying drawings in which:
  • FIG. 1 Ba longitudinal section through a hydraulic :actuator according to the invention
  • FIG. Zis a diagram showing schematically an actuator with'its associated electric feed-back circuit.
  • the actuator comprises a body 1 having a bore 2 for the piston 3.
  • the piston is formed integrally with a piston rod 4, the outer end of which is provided at 5 with means apparatus to be actuated.
  • a system pressure inlet 6 communicates with a gallery 7 by means of which system pressure is applied to the annular area between the piston and piston rod.
  • the cross-section of the piston rod is half that of the piston itself. so the system pressure acts effectively over hall the piston area.
  • the pressure inlet 6 also communicates by way of a fixed orifice 8 with a chamber 9 at the other end of the piston. From this it can escape to tank through a varifor coupling it to the able orifice formed between'the flapper disc 10 and the sharpened edge of an outlet tube ll.
  • the opposite side of the flapper disc 10 carries a counter-balance tube l2.working in a bore 13 in the piston rod, and maintained at tank pressure by means of a passageway 14, in the flapper disc.
  • a passageway 14 in the flapper disc.
  • the pressure on both sides of the disc 10 is equalized. by means of the passage 14. Outside this perimeter the pressure on both sides of the disc 10 is equal, being merely the pressure in the chamber 9.
  • the forces acting on the disc 10 are therefore in balance, except for the relatively small Bernouilli force due to the flow of fluidthrough the gap between the flapper disc '10 and the sharpened edge of the outlet tube 11.
  • the flapper disc is coupled by a rod or cable 15 to the armature 17 of a solenoid, and is also acted on by a spring 18 urging it towards the open position, while a further spring 19 acts on the armature to urge it in the opposite direction.
  • a cover 20 encloses the solenoid.
  • the space 21 surrounding the armature is filled in operation with fluid at tank pressure and communicates with tank by means of a tank port 22.
  • the actuator is coupled at 5 to the equipment which it is required to operate and is also linked to an electric pick-off 23 which may be, for example, an inductive or capacitive pick-off or of the potentiometric type.
  • the signal from this pick-off is summed with a demand signal from a signal source 25 at the junction 26, and the resultant error signal is fed to the solenoid winding of the actuator.
  • the amplifier 24 is arranged to include a standing bias current so as to eliminate any residual stand-off error.
  • the output from the pick-off 23 represents the position of the actuator, and the amplified signal fed to the solenoid causes the actuator to move in such a direc tion as to reduce the position error, between demanded position from 25 and the actual position of the actuator.
  • the centering springs 18 and 19 are initially set up so that the flapper disc 10 stands clear of the outlet tube 11 when no current is passing through the solenoid, and when about half the maximum operating current is passed through the solenoid the flapper disc moves so that the pressure in the 'chamber9 is half the full system pressure, at which point the forces on the two sides of the piston 3 are in balance.
  • the extension of the actuator falls short of that called for by the demand signal from source 25.
  • the resulting error signal which is amplified by the amplifier 24, increasing the solenoid current, drawing the flapper disc 10 closer to the outlet tube 1 l, and so increasing the pressure at the inner side of the piston, causing it to extend. If the position error is in the opposite sense the feedback signal reduces the solenoid current, allowing the flapper disc 10 to move away from the end of the outlet tube 11, the pressure in the chamber 9 to drop, and the piston to be forced inwards by the pressure in the gallery 7.
  • An electro-pneumatic actuator and feed-back circuit according to the invention are constructed and operate in the same manner. However. different valves will be necessary for the apertures of the restrictors, and additional damping will generally be required in the feedback circuit.
  • An actuator comprising a body having a bore. a piston in said bore and having a piston rod.
  • said body including a system pressure passage arranged for the application of system pressure to the annular area between said piston and said piston rod, and a chamber for'applying pressure to the other end of said piston, a fixed orifice through which said chamber communicates with said system pressure passage through said fixed orifice, and a flapper disc arranged to close the end of an outlet tube and provide an exhaust outlet through a variable orificecontrolled by said flapper disc, a pressure balancing tube of the same diameter as the outlet tube on the opposite face of said flapper disc, said piston rod having a bore, thepressure balancing tube working in said bore in said piston rod, passageway means for maintaining the pressure in said last mentioned hore equal to the exhaust pressure.
  • a solenoid having a spring centered armature controlling said flapper disc.
  • An actuator according to claim 1 designed for op-' cration with hydraulic fluid.
  • An actuator according to claim 1 in combination with an electric feed-back circuit whereby the current to the actuator solenoid is controlled in dependence on the position of the piston rod and an external demand signal.

Landscapes

  • Engineering & Computer Science (AREA)
  • Physics & Mathematics (AREA)
  • Fluid Mechanics (AREA)
  • Mechanical Engineering (AREA)
  • General Engineering & Computer Science (AREA)
  • Servomotors (AREA)
  • Actuator (AREA)
  • Fluid-Pressure Circuits (AREA)
US444166A 1973-02-26 1974-02-20 Electro-hydraulic actuator Expired - Lifetime US3902402A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
GB928273A GB1465674A (en) 1973-02-26 1973-02-26 Electrically-operated fluid actuator

Publications (1)

Publication Number Publication Date
US3902402A true US3902402A (en) 1975-09-02

Family

ID=9868987

Family Applications (1)

Application Number Title Priority Date Filing Date
US444166A Expired - Lifetime US3902402A (en) 1973-02-26 1974-02-20 Electro-hydraulic actuator

Country Status (6)

Country Link
US (1) US3902402A (it)
JP (1) JPS5911041B2 (it)
DE (1) DE2409066A1 (it)
FR (1) FR2219323B1 (it)
GB (1) GB1465674A (it)
IT (1) IT1003590B (it)

Cited By (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
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
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
US5421294A (en) * 1991-08-29 1995-06-06 Robert Bosch Gmbh Hydraulic setting device

Families Citing this family (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS52143954A (en) * 1976-05-26 1977-11-30 Akira Takayasu Inner strengthen pipe manufacturing
CH640610A5 (de) * 1979-10-02 1984-01-13 Elektrowatt Ag Stellantrieb.
DE2947627C2 (de) * 1979-11-27 1984-05-24 Shoketsu Kinzoku Kogyo K.K., Tokyo Druck- und explosionssichere Stellvorrichtung
DE3046595A1 (de) * 1980-12-11 1982-07-22 G. Kromschröder AG, 4500 Osnabrück Regelventilanordnung
EP0097007A3 (en) * 1982-06-15 1984-08-01 William Richards Price A hydraulic control system
US4832999A (en) * 1987-10-27 1989-05-23 Avco Lycoming/Textron Honeycomb structure assemblies

Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US1496136A (en) * 1920-11-19 1924-06-03 Rateau Battu Smoot Engineering Magnetic and fluid regulation of electric current
US3516331A (en) * 1967-03-21 1970-06-23 Chandler Evans Inc Time modulated hydraulically actuated control mechanism
US3720118A (en) * 1971-03-17 1973-03-13 Delta Hydraulics Inc Integrated servo actuator

Family Cites Families (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB789670A (en) * 1954-10-13 1958-01-29 Rolls Royce Improvements relating to hydraulic speed responsive circuits
FR1364650A (fr) * 1963-05-02 1964-06-26 Ct De Rech S Hydrauliques Et E Servo-commande électro-hydraulique, à contre-réaction pour commandes de force
US3521535A (en) * 1967-11-07 1970-07-21 Chandler Evans Inc Time modulated pneumatically actuated position control mechanism
GB1444910A (en) * 1972-09-29 1976-08-04 Sperry Rand Ltd Electro-hydraulic actuator

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US1496136A (en) * 1920-11-19 1924-06-03 Rateau Battu Smoot Engineering Magnetic and fluid regulation of electric current
US3516331A (en) * 1967-03-21 1970-06-23 Chandler Evans Inc Time modulated hydraulically actuated control mechanism
US3720118A (en) * 1971-03-17 1973-03-13 Delta Hydraulics Inc Integrated servo actuator

Cited By (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
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
US5421294A (en) * 1991-08-29 1995-06-06 Robert Bosch Gmbh Hydraulic setting device

Also Published As

Publication number Publication date
GB1465674A (en) 1977-02-23
JPS5911041B2 (ja) 1984-03-13
FR2219323B1 (it) 1976-10-08
JPS5024694A (it) 1975-03-15
DE2409066A1 (de) 1974-09-05
FR2219323A1 (it) 1974-09-20
IT1003590B (it) 1976-06-10

Similar Documents

Publication Publication Date Title
US2896588A (en) Electro-hydraulic servo valve
US3910314A (en) High-speed shutoff and dump valve
US3202413A (en) Fluid-pressure devices for vehicle suspensions or the like
US4848721A (en) Hydraulic valve with integrated solenoid
US4201116A (en) Electro-hydraulic proportional control servo valve
US3902402A (en) Electro-hydraulic actuator
US4569273A (en) Three-way proportional valve
US2964059A (en) Pressure-flow servo valve
GB685353A (en) Improvements in or relating to electro-hydraulic servo mechanism
US2861550A (en) Hydraulic power control valve
US2447820A (en) Regulating valve
US4667472A (en) Electric integrated actuator with variable gain hydraulic output
US4275758A (en) Pressure control valve assembly
US4362182A (en) Nozzle force feedback for pilot stage flapper
US5735122A (en) Actuator with failfixed zero drift
US3023781A (en) Hydraulic servo valves
US3401711A (en) Single receiver port jet displacement servovalve
EP0224478B1 (en) Load sensing circuit of load responsive direction control valve
US2889815A (en) Pressure feedback servo valve
US2866476A (en) Electro-magnetically operated control valves
US3555969A (en) Servovalve having dynamic load adaptive response while maintaining static performance unaffected
US3065735A (en) Servoactuator
US2962002A (en) Two-stage hydraulic servo valve
US5095804A (en) Drive for a steam servo valve
US3223104A (en) Electro-hydraulic servo valve

Legal Events

Date Code Title Description
AS Assignment

Owner name: VICKERS, INCORPORATED, 1401 CROOKS ROAD, TROY, MI.

Free format text: ASSIGNMENT OF ASSIGNORS INTEREST.;ASSIGNOR:SPERRY LIMITED;REEL/FRAME:004548/0147

Effective date: 19860303

Owner name: VICKERS, INCORPORATED, MICHIGAN

Free format text: ASSIGNMENT OF ASSIGNORS INTEREST;ASSIGNOR:SPERRY LIMITED;REEL/FRAME:004548/0147

Effective date: 19860303