US3598020A - Main control system for hydraulic servomotors - Google Patents

Main control system for hydraulic servomotors Download PDF

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Publication number
US3598020A
US3598020A US3598020DA US3598020A US 3598020 A US3598020 A US 3598020A US 3598020D A US3598020D A US 3598020DA US 3598020 A US3598020 A US 3598020A
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Prior art keywords
diaphragm
corresponding side
chamber
piston
circular
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Expired - Lifetime
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English (en)
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Petrus Blok
Taco J Viersma
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Classifications

    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B23—MACHINE TOOLS; METAL-WORKING NOT OTHERWISE PROVIDED FOR
    • B23Q—DETAILS, COMPONENTS, OR ACCESSORIES FOR MACHINE TOOLS, e.g. ARRANGEMENTS FOR COPYING OR CONTROLLING; MACHINE TOOLS IN GENERAL CHARACTERISED BY THE CONSTRUCTION OF PARTICULAR DETAILS OR COMPONENTS; COMBINATIONS OR ASSOCIATIONS OF METAL-WORKING MACHINES, NOT DIRECTED TO A PARTICULAR RESULT
    • B23Q35/00—Control systems or devices for copying directly from a pattern or a master model; Devices for use in copying manually
    • B23Q35/04—Control systems or devices for copying directly from a pattern or a master model; Devices for use in copying manually using a feeler or the like travelling along the outline of the pattern, model or drawing; Feelers, patterns, or models therefor
    • B23Q35/08—Means for transforming movement of the feeler or the like into feed movement of tool or work
    • B23Q35/18—Means for transforming movement of the feeler or the like into feed movement of tool or work involving fluid means
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B23—MACHINE TOOLS; METAL-WORKING NOT OTHERWISE PROVIDED FOR
    • B23Q—DETAILS, COMPONENTS, OR ACCESSORIES FOR MACHINE TOOLS, e.g. ARRANGEMENTS FOR COPYING OR CONTROLLING; MACHINE TOOLS IN GENERAL CHARACTERISED BY THE CONSTRUCTION OF PARTICULAR DETAILS OR COMPONENTS; COMBINATIONS OR ASSOCIATIONS OF METAL-WORKING MACHINES, NOT DIRECTED TO A PARTICULAR RESULT
    • B23Q5/00—Driving or feeding mechanisms; Control arrangements therefor
    • B23Q5/22—Feeding members carrying tools or work
    • B23Q5/26—Fluid-pressure 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
    • 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
    • F15B13/0401—Valve members; Fluid interconnections therefor
    • F15B13/0402—Valve members; Fluid interconnections therefor for linearly sliding valves, e.g. spool 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
    • F15B13/00—Details of servomotor systems ; Valves for servomotor systems
    • F15B13/16—Special measures for feedback, e.g. by a follow-up device
    • 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
    • F15B9/16—Systems essentially having two or more interacting servomotors, e.g. multi-stage
    • 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
    • Y10T137/2278—Pressure modulating relays or followers

Definitions

  • a control system for a hydraulic servomotor comprising a cylinder chamber containing a diaphragm which is borne, between two circular bearing edges so that a central and an annular compartment are produced on either side of the diaphragm, each of the annular compartments being connected to a pilot system, the first central compartment being connected to a cylinder of a servomotor, and the second to a discharge, in each central compartment an outflow member discharging towards the center of the diaphragm the member in the first compartment connected to a high-pressure supply and the other member to said cylinder.
  • the invention relates to a main control system for a hydraulic servomotor, comprising a supply of high-pressure liquid at substantially constant pressure, which can be connected via an adjustable inlet aperture to a cylinder chamber of the servomotor, the main control system also having a discharge to a low-pressure reservoir, which can also be connected via an adjustable outflow aperture to the aforementioned cylinder chamber, a displaceable member being provided to adjust the size of the inlet and outlet apertures, whose condition can be adjusted by means of a control system, while the pressure in the cylinder chamber so acts on the displaceable member that when the pressure rises, the inlet aperture increases in size and the outlet aperture decreases in size, and vice versa.
  • the displaceable member is a control disc whose movement inside a casing opens the inlet and outlet apertures to varying degrees.
  • the reaction of the pressure in the cylinder chamber is obtained by making this pressure act on a diaphragm to which the control disc is connected.
  • One disadvantage of this system is its rather complicated construction and the fact that the control disc has a relatively large mass, thus reducing the control speed.
  • the main control system is characterized in that it comprises a closed cylinder chamber containing a circular diaphragm which has a diameter at least substantially the same as that of the cylinder chamber and over smaller diameter than that of the outer periphery ofthe diaphragm is borne between two circular eonstructional members bearing in sealingtight relationship against the end walls of the cylinder chamber and the diaphragm, so that an annular compartment and a central compartment are produced on either side of the diaphragm, and each of the annular compartments can be connected to a pilot control system delivering two control pressures one central compartment being connectable to the aforementioned cylinder chamber of the servomotor, the other central compartment being connectable to the discharge, while the highpressure liquid supply discharges via an outflow aperture directed towards the center of the diaphragm into the compartment which can be connected to said cylinder chamber, and an outflow member whose outflow aperture is directed towards the center of the diaphragm and whose other side can be connected to the said pilot control system delivering two
  • the result is a main control valve of very compact construction which is well adapted to be incorporated in the piston of the servomotor, thus making the servomotor itself more compact. Sensitivity and control speed are high, due to the small mass of the moving diaphragm.
  • the main control valve can also be controlled by a hydraulic or pneumatic pilot valve.
  • each ofthe constructional members bearing the diaphragm is formed by the combination of a number of balls received in an annular cage with an O-ring gasket on one or both sides thereof.
  • FIG. 1 shows diagrammatically (not to scale) a servomotor main control system cooperating with a pilot control system
  • FIG. 2 shows diagrammatically (not to scale) a variant embodiment of the main control system shown in FIG. 1, and
  • FIG. 3 shows diagrammatically (not to scale) an embodiment of a servomotor in which the main control system is incorporated in the servomotor piston.
  • a main control system 1 comprises a closed cylindrical casing 2 receiving a circular diaphragm 3 having substantially the same diameter as the casing 2. Over a diameter smaller than its peripheral diameter, the diaphragm 3 is loosely borne between two circular knife-edge-like bearing edges 4, 5 which bear in sealingtight relationship against the diaphragm 3 and and are also rigidly connected to the walls of the casing 2, thus forming two annular compartments 6, 7 and two central compartments 8, 9. Disposed in the center of each of the end walls of the casing 2 is an outflow member 10, 11 whose outflow apertures 12, 13 respectively are turned towards the diaphragm 3. The outflow member 10 is connected via a supply line 14 to cylinder chamber 15 of a servomotor 16.
  • the chamber 15 is connected via a line 17 to a pump (not shown) delivering high-pressure liquid at a substantially constant pressure.
  • the central compartment 8 into which the supply line 14 discharges via outflow aperture 12 is connected via a line 18 to chamber 19 of the servomotor 16.
  • the chamber 19 is also connected via a discharge duct 20 to the outflow member 11, which discharges via its outflow aperture 13 into the central compartment 9 which is in open communication via aperture 21 with a collecting reservoir (not shown).
  • a pilot control system 22 delivers, in dependence on an input signal, two control pressures p,, p, which pass via lines 23, 24 to the compartments 6, 7.
  • the diaphragm 3 occupies the position shown in chain lines. In this position the distance between the diaphragm and the outflow member 10 is reduced, and that between the diaphragm and the outflow member 11 is increased. Consequently, the liquid flow from the supply duct 14 to the compartment 8 and therefore to the chamber 19 is reduced, while the liquid flow from the chamber 19 via duct 20 and outflow aperture 13 is increased. As a result, the piston 25 moves to the right.
  • the diaphragm 3 occupies the chain-dash line, in which the distance between the diaphragm and outflow aperture 12 is increased and the distance between the diaphragm and outflow aperture 13 is reduced.
  • the liquid flow to the chamber 19 is increased, and the liquid flow from the chamber 19 is reduced, so that the piston 25 moves to the left.
  • FIG. 2 shows a slightly different embodiment of the main control system illustrated in FIG. 1.
  • the place of the bearing edges 4, 5 is taken by a number of balls 31 received in a circular cage 30 and having an O-ring gasket 32, 33 on both sides thereof.
  • the advantage is that the diaphragm 8 cannot get jammed between its bearings, thus possibly impeding the deformation of the diaphragm. Being borne on balls ensures that when it is deformed, the diaphragm can move to a slight extent between the balls. Since the pressure in compartment 9 is always lower than the pressure in compartment 7, if necessary the O-ring 33 can be omitted from compartment 9 without any adverse effeet on sealingtightness.
  • FIG. 3 shows diagrammatically a servomotor with the main control system incorporated in its piston.
  • FIGS. 1 and 3 like elements have like references.
  • the servomotor 16 comprises a cylinder 27 which can move over a fixed guide 28 to which a piston rod 29 is rigidly connected.
  • the piston rod 29 is connected to a piston 25 containing a main control system as illustrated in FIG. 1.
  • the piston 25 has a cylindrical chamber containing a diaphragm 3 borne by circular bearing edges 4, 5, thus forming compartments 6, 7, 8, 9.
  • the center of the end face of the piston 25 is formed with an outflow member 11 whose outflow aperture 13 points towards the diaphragm 3 and which is also in open communication with the cylinder chamber 19 containing a pressure p Disposed on the other side of the diaphragm is an outflow member whose outflow aperture 12 also points towards the diaphragm and whose other side is connected via duct 14 to cylinder chamber 15 in which there is a constant pressure p,.
  • the chamber 15 is connected via a line 17 to a pump (not shown) delivering liquid at a substantially constant pressure.
  • the compartment 8 is connected to the chamber 19 via a duct 18, while the compartment 9 is connected via a duct 21 to a low-pressure reservoir (not shown).
  • the system also comprises a pilot control system 22.
  • the pilot control system 22 comprises a l-l-shaped yoke 40 bearing a sensor 41 cooperating with the cam 42. Disposed between the arms of the yoke are two outflow members 43, 44.
  • the outflow member 43 has an outflow aperture 45 pointing to the left and its other side is sealed by a mobile ball 46 having a somewhat larger diameter than that of the outflow aperture.
  • Chamber 47 in the outflow member 43 is connected via a constriction 48 to duct 49 connected to line 17 in which there is a substantially constant liquid pressure.
  • the outflow member 44 has an outflow aperture 50 pointing to the right and its other side is sealed by a mobile ball 51 of somewhat larger diameter than the outflow aperture.
  • Chamber 52 in the outflow member 44 is also connected via a constriction 53 to duct 49.
  • the two outflow members 43, 44 are disposed in a structural member 55 rigidly COIII ICCIed to the cylinder 27.
  • the yoke 40 is disposed on two resilient strips 56, 57 connected on their other sides to the cylinder 27.
  • Chamber 47 in the outflow member 43 is connected via a duct 23 to a compartment 6, while chamber 52 in the outflow member 44 is connected via a line 24 to compartment 7.
  • a casing having a cylindrical inner wall and spaced sidewalls defining a cylindrical chamber
  • a pair of retainer means each disposed between a respective one of said sidewalls and a corresponding side of said diaphragm and each sealingly engaging its corresponding side of the diaphragm along a circular path inwardly offset from said inner wall to separate said chamber into a pair of annular compartments on opposite sides of the outer marginal area of said diaphragm and a pair of central compartments on opposite sides of the central area of said diaphragm;
  • each said retainer means comprises a circular wall having a knife edge bearing against a corresponding side of said diaphragm.
  • each said retainer means comprises a circular row of balls interposed between a corresponding side wall of the casing and a corresponding side of said diaphragm, and at least one O-ring concentric with and adjacent said row of balls.
  • each said retainer means comprises a circular wall having a knife edge bearing against a corresponding side of said diaphragm.
  • each said retainer means comprises a circular row of balls interposed between a corresponding side wall of the casing and a corresponding side of said diaphragm, and at least one O-ring concentric with and adjacent said row of balls.

Landscapes

  • Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • Physics & Mathematics (AREA)
  • Fluid Mechanics (AREA)
  • General Engineering & Computer Science (AREA)
  • Automation & Control Theory (AREA)
  • Fluid-Pressure Circuits (AREA)
  • Actuator (AREA)
  • Servomotors (AREA)
US3598020D 1968-05-31 1969-05-19 Main control system for hydraulic servomotors Expired - Lifetime US3598020A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
NL6807776A NL6807776A (fr) 1968-05-31 1968-05-31

Publications (1)

Publication Number Publication Date
US3598020A true US3598020A (en) 1971-08-10

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ID=19803804

Family Applications (1)

Application Number Title Priority Date Filing Date
US3598020D Expired - Lifetime US3598020A (en) 1968-05-31 1969-05-19 Main control system for hydraulic servomotors

Country Status (9)

Country Link
US (1) US3598020A (fr)
AT (1) AT306473B (fr)
BE (1) BE733484A (fr)
CH (1) CH493033A (fr)
DE (1) DE1927649C3 (fr)
FR (1) FR2009711A1 (fr)
GB (1) GB1266233A (fr)
NL (1) NL6807776A (fr)
SE (1) SE350102B (fr)

Cited By (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4173984A (en) * 1978-06-12 1979-11-13 S/P Product Design, Inc. Pneumatic amplifier
US4265164A (en) * 1978-04-24 1981-05-05 Kabushiki Kaisha Asahi Enterprise Pressure detecting device
US4327864A (en) * 1980-09-30 1982-05-04 The Boeing Company Multiple function pneumatic thermostat
US4350209A (en) * 1979-08-06 1982-09-21 Allis-Chalmers Corporation Hydraulic draft control valve
US4705059A (en) * 1985-06-10 1987-11-10 Centre Technique Des Industries Mecaniques Electrofluidic transducer of the nozzle/plate type and hydraulic servo-valve equipped with such a transducer
US20110032069A1 (en) * 2008-04-10 2011-02-10 Siemens Aktiengesellschaft Method for producing a transformer core and a transformer core

Families Citing this family (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE2946274C2 (de) * 1979-11-16 1981-11-12 Danfoss A/S, 6430 Nordborg Hydraulische Steuervorrichtung, insbesondere Lenkvorrichtung

Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2725040A (en) * 1951-04-25 1955-11-29 Lucas Industries Ltd Control means for servo-mechanism of the kind having output means operable by liquid pressure and a control member therefor
US2838028A (en) * 1955-03-08 1958-06-10 Daystrom Inc Pneumatic follow-up system
US3257912A (en) * 1963-12-30 1966-06-28 Floyd K Haskell Force amplifier

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2725040A (en) * 1951-04-25 1955-11-29 Lucas Industries Ltd Control means for servo-mechanism of the kind having output means operable by liquid pressure and a control member therefor
US2838028A (en) * 1955-03-08 1958-06-10 Daystrom Inc Pneumatic follow-up system
US3257912A (en) * 1963-12-30 1966-06-28 Floyd K Haskell Force amplifier

Cited By (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4265164A (en) * 1978-04-24 1981-05-05 Kabushiki Kaisha Asahi Enterprise Pressure detecting device
US4173984A (en) * 1978-06-12 1979-11-13 S/P Product Design, Inc. Pneumatic amplifier
US4350209A (en) * 1979-08-06 1982-09-21 Allis-Chalmers Corporation Hydraulic draft control valve
US4327864A (en) * 1980-09-30 1982-05-04 The Boeing Company Multiple function pneumatic thermostat
US4705059A (en) * 1985-06-10 1987-11-10 Centre Technique Des Industries Mecaniques Electrofluidic transducer of the nozzle/plate type and hydraulic servo-valve equipped with such a transducer
US20110032069A1 (en) * 2008-04-10 2011-02-10 Siemens Aktiengesellschaft Method for producing a transformer core and a transformer core
US8212645B2 (en) * 2008-04-10 2012-07-03 Siemens Aktiengesellschaft Method for producing a transformer core and a transformer core

Also Published As

Publication number Publication date
DE1927649B2 (de) 1973-03-08
DE1927649A1 (de) 1969-12-04
NL6807776A (fr) 1969-12-02
SE350102B (fr) 1972-10-16
BE733484A (fr) 1969-11-03
FR2009711A1 (fr) 1970-02-06
DE1927649C3 (de) 1973-09-27
AT306473B (de) 1973-04-10
CH493033A (de) 1970-06-30
GB1266233A (fr) 1972-03-08

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