US3893377A - Hydraulic servomotor - Google Patents

Hydraulic servomotor Download PDF

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Publication number
US3893377A
US3893377A US404337A US40433773A US3893377A US 3893377 A US3893377 A US 3893377A US 404337 A US404337 A US 404337A US 40433773 A US40433773 A US 40433773A US 3893377 A US3893377 A US 3893377A
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United States
Prior art keywords
accumulator
diaphragm
compartment
hydraulic
servomotor
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
US404337A
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English (en)
Inventor
Jacob Johan T Mannetje
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.)
US Philips Corp
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US Philips Corp
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Filing date
Publication date
Application filed by US Philips Corp filed Critical US Philips Corp
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Publication of US3893377A publication Critical patent/US3893377A/en
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Classifications

    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F15—FLUID-PRESSURE ACTUATORS; HYDRAULICS OR PNEUMATICS IN GENERAL
    • F15B—SYSTEMS ACTING BY MEANS OF FLUIDS IN GENERAL; FLUID-PRESSURE ACTUATORS, e.g. SERVOMOTORS; DETAILS OF FLUID-PRESSURE SYSTEMS, NOT OTHERWISE PROVIDED FOR
    • F15B15/00—Fluid-actuated devices for displacing a member from one position to another; Gearing associated therewith
    • F15B15/20—Other details, e.g. assembly with regulating devices
    • F15B15/22—Other details, e.g. assembly with regulating devices for accelerating or decelerating the stroke
    • 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
    • F15B1/00—Installations or systems with accumulators; Supply reservoir or sump assemblies
    • F15B1/02—Installations or systems with accumulators
    • 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
    • F15B15/00—Fluid-actuated devices for displacing a member from one position to another; Gearing associated therewith
    • F15B15/08—Characterised by the construction of the motor unit
    • F15B15/14—Characterised by the construction of the motor unit of the straight-cylinder type
    • F15B15/1423—Component parts; Constructional details
    • F15B15/1433—End caps
    • 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
    • F15B15/00—Fluid-actuated devices for displacing a member from one position to another; Gearing associated therewith
    • F15B15/08—Characterised by the construction of the motor unit
    • F15B15/14—Characterised by the construction of the motor unit of the straight-cylinder type
    • F15B15/149—Fluid interconnections, e.g. fluid connectors, passages
    • 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
    • F15B21/00—Common features of fluid actuator systems; Fluid-pressure actuator systems or details thereof, not covered by any other group of this subclass
    • F15B21/008—Reduction of noise or vibration

Definitions

  • HYDRAULIC SERVOMOTOR The invention relates to a hydraulic servomotor comprising one or two controlled motor spaces and a valve for controlling hydraulic medium flow from and to each of the motor spaces.
  • a controlled motor space is to be understood to mean herein a motor space in which the pressure of the hydraulic medium is adjustable so as to exert a force of a desired value.
  • the servomotor may be of the lfifzar type in which either the pressure on either side of a piston is adjustable (two motor spaces), or the pressure on one side of a plunger is controllable and is constant on the other side (one motor space).
  • the servomotor may also be constructed as a rotating motor.
  • Such hydraulic servomotors may be used in a variety of fields of technology.
  • hydraulic power amplifiers have poor dynamic properties (very small damping).
  • the effects of low damping are particularly noticeable, for example, in chipping operations or in rapid positioning.
  • the resulting residual vibration keeps a member connected to the piston rod from assuming the desired position accurately and without vibration, within a desired period of time.
  • This drawback is very obvious particularly when the hydraulic motor is used as a drive of a slide or another member in microtechnology, such as the manufacture of masks for semiconductor manufacture.
  • the object of the invention is to provide a hydraulic servomotor which has a sufficiently large damping and in which a detrimental oscillation of the piston is prevented so that a high adjusting rate can be obtained.
  • an accumulator is connected to each of the motor spaces, a flexible diaphragm being provided in each accumulator and dividing the accumulator space into a compartment which the hydraulic medium enters or leaves via a restriction and a compartment in which a gas under pressure is present.
  • a differential pressure across, for example, the piston of a linear servomotor arising from forces of acceleration or operation is smoothed by the accumulator so that oscillation of the piston is prevented by the increased damping.
  • the accumulators may be connected to the motor spaces via a short wide pipe. in a preferred embodiment, however, the accumulator is arranged in the motor space. This is possible because the accumulator requires only a small volume for good performance. This location also provides the possibility of optimum damping.
  • the restriction consists of one or more capillary resistances which produce laminar flow. In this case a truly linear variation of the flow resistance of the restriction is ensured.
  • each of the accumulators comprises a disk-shaped member and a block-shaped member, the disk-shaped member comprising a number of restrictions communicating with the motor space and the accumulator space being provided in the block-shaped member.
  • the flexible diaphragm may be provided near its circumference with a ring which is clamped between the disk-shaped member and the block-shaped member in a recess having a smaller volume than the ring.
  • the diaphragm may also be constructed to be tubular. and be located in the accumulator space.
  • FIG. I is a diagram showing the principle of a hydraulic servomotor according to the invention.
  • FIG. 2 is a sectional view of a hydraulic servomotor having accumulators incorporated in the motor spaces.
  • FIG. 3 is a sectional view showing a connection of the diaphragm of the accumulators.
  • FIG. 4 is a sectional view of a diaphragm having a tubular construction.
  • a linear hydraulic servomotor shown in FIG. I comprises a cylinder 1 and a piston 2.
  • the piston rod 3 in this embodiment is passed out of the cylinder on two sides, a slide 4 to be adjusted. for example, being secured to the piston rod 3 on one side.
  • a duct 5 for the supply of hydraulic medium is connected, which ducts 5 communicate with a control valve 6.
  • the piston 2 and hence the slide 4 can be placed in a desired position by means of the control valve 6.
  • a hydraulic servomotor is suitable for exerting great forces. Due to the inherently small damping in such a motor the damping factor is approximately 0.001 in a hydrostatically journalled slide to approximately 0.1 in a nonhydrostatically journalled slide the desired vibration-free adjustment cannot be obtained in a short period of time.
  • an accumulator 7 is connected to each of the ducts 5.
  • a diaphragm 8 divides the accumulator space into two compartments 9 and 10. Compartment 10 contains a gas under pressure, for example nitrogen. Compartment 9 communicates with the duct 5 via a restriction 11.
  • the damping is considerably increased. Damping factors from 0.5 to 0.8 are easy to obtain. A higher damping is usually not desired since the operation of the servomotor may then become too inert.
  • the damping is independent of the position of the piston, the construction is simple and the reliability is great.
  • One of the applications of such a hydraulic servomotor is to drive a slide in manufacturing masks for semiconductor production. Very short adjusting times are desired to provide an economically justified process.
  • FIG. 2 is a cross-sectional view of a preferred embodiment of a hydraulic servomotor having accumulators for damping undesired pressure variations.
  • a piston 16 is present in the cylinder 15; piston rods 17 are passed through the covers 18 of the cylinder (one end of which is shown in the drawing).
  • the control valve as well as the ducts for supplying hydraulic medium to the motor spaces 19, 20 are not shown.
  • the accumulators 2] are incorporated in the covers 18 of the cylinder. Very small volume accumulators will suffice, the volume in the embodiment shown being approximately 2% of the volume of a motor space. Arranging the accumulators immediately adjacent the motor space incorporation in the piston is also possible is advantageous for satisfactory operation.
  • Each of the accumulators 21 comprises a blockshaped member 22 in which the accumulator space is accommodated.
  • a flexible diaphragm 23 is clamped between the block-shaped member 22 and a diskshaped member 24 of the cover 18, dividing the accumulator into compartments 26 and 27.
  • a number of restrictions in the form of capillary resistances I through the member 24 connect the compartment 27 to the motor space 19.
  • a gas under pressure, for example, nitrogen, is present in compartment 26, which is sealed by means of a screw 28. Via the restrictions 25, hydraulic medium can fllow into the compartment 27 or flow out of it until the gas pressure and the medium pressure cause the diaphragm 23 to assume an equilibrium position.
  • the overall value of the capillary resistance can be controlled at will, for example, by sealing a number of the restrictions 25 by means of a bolt.
  • the diaphragm may be provided with an annular thickening 29, see FIG. 3, which is clamped in a recess 30 having a smaller volume than the ring 29.
  • the recess 30 may be present in both members 22 and 24 or in one of the two. It is furthermore possible, as is shown in FIG. 4, to give the diaphragm 23 a tubular construction.
  • the diaphragm has a nipple 31 for supplying the gas under pressure.
  • the three sides of the diaphragm 23 adjoining the block-shaped member 22 are preferably vulcanized on those sides.
  • the embodiments shown in the figures relate to a symmetrical linear servomotor. However, the invention may also be used in an asymmetric linear servomotor and in a rotating servomotor.
  • a hydraulic servomotor comprising a controlled motor space, means for conducting hydraulic medium to said space, and means for damping oscillations of pressure of the hydraulic medium, said damping means comprising an accumulator having first and second compartments separated by a flexible diaphragm, said accumulator comprising a disk member and a block member, said disk member being a wall of said first compartment, and a viscous flow restriction means for connecting said first compartment directly to said motor spaces, said viscous flow restriction means being at least one restrictive passage through said disk memher. said second compartment containing a gas under pressure.
  • a hydraulic servomotor as claimed in claim I wherein said diaphragm has a tubular construction enclosing a variable volume, said second compartment being the volume enclosed within the tubular diaphragm.

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  • Engineering & Computer Science (AREA)
  • Physics & Mathematics (AREA)
  • Fluid Mechanics (AREA)
  • Mechanical Engineering (AREA)
  • General Engineering & Computer Science (AREA)
  • Chemical & Material Sciences (AREA)
  • Analytical Chemistry (AREA)
  • Supply Devices, Intensifiers, Converters, And Telemotors (AREA)
  • Actuator (AREA)
  • Fluid-Pressure Circuits (AREA)
US404337A 1972-10-17 1973-10-09 Hydraulic servomotor Expired - Lifetime US3893377A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
NL7214004A NL7214004A (enrdf_load_stackoverflow) 1972-10-17 1972-10-17

Publications (1)

Publication Number Publication Date
US3893377A true US3893377A (en) 1975-07-08

Family

ID=19817169

Family Applications (1)

Application Number Title Priority Date Filing Date
US404337A Expired - Lifetime US3893377A (en) 1972-10-17 1973-10-09 Hydraulic servomotor

Country Status (6)

Country Link
US (1) US3893377A (enrdf_load_stackoverflow)
JP (1) JPS4972573A (enrdf_load_stackoverflow)
DE (1) DE2349392A1 (enrdf_load_stackoverflow)
FR (1) FR2203032B1 (enrdf_load_stackoverflow)
GB (1) GB1448880A (enrdf_load_stackoverflow)
NL (1) NL7214004A (enrdf_load_stackoverflow)

Cited By (10)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4785921A (en) * 1985-01-16 1988-11-22 Stabilus Gmbh Temperature-compensating hydraulic positioner
US4932197A (en) * 1988-12-28 1990-06-12 Allen David R Apparatus for positioning a work implement
US4941542A (en) * 1986-10-01 1990-07-17 Mazda Motor Corporation Automotive four wheel steering system
US4982638A (en) * 1988-02-19 1991-01-08 Fried. Krupp Gesellschaft Mit Beschrankter Haftung Pneumatically operated cutting device
WO2006123014A1 (en) * 2005-05-20 2006-11-23 Metso Paper, Inc. An actuator means to accomplish a linear movement
WO2007006557A1 (de) 2005-07-11 2007-01-18 Laeis Gmbh Kolben-zylinder-anordnung
US7634909B1 (en) * 2005-05-13 2009-12-22 Probir Chatterjea Articulated loader steering system
FR2959782A1 (fr) * 2010-05-10 2011-11-11 Snecma Verin pour un circuit de fluide, tel par exemple qu'un circuit de carburant dans une turbomachine
WO2014127955A1 (de) * 2013-02-21 2014-08-28 Saf-Holland Gmbh Hydraulikeinheit
US10273732B2 (en) * 2016-05-23 2019-04-30 D&D Builders Hardware Co., Ltd. Lightly opening and bufferably closing door closer

Families Citing this family (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE3044675A1 (de) * 1980-11-27 1982-07-08 Leybold-Heraeus GmbH, 5000 Köln Verfahren zur steuerung eines hydraulischen antriebs und fuer die durchfuehrung dieses steuerungsverfahrens geeigneter hydraulischer antrieb
JPS6222301U (enrdf_load_stackoverflow) * 1985-07-25 1987-02-10
JP5031386B2 (ja) * 2007-01-31 2012-09-19 東京計器株式会社 液圧機器の圧力保持機構
GB2603748A (en) * 2020-11-09 2022-08-17 Bamford Excavators Ltd Hydraulic actuator

Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2032398A (en) * 1934-03-30 1936-03-03 Rca Corp Film drive mechanism
US2393324A (en) * 1942-09-18 1946-01-22 Joseph F Joy Automotive vehicle
US2482792A (en) * 1944-05-27 1949-09-27 Nasser D Owen Single-line hydraulic system

Family Cites Families (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2638932A (en) * 1948-04-10 1953-05-19 George E Failing Supply Compan Pressure equalizer
DE1087454B (de) * 1959-03-12 1960-08-18 Licentia Gmbh Hydraulischer Antrieb
DE7010564U (de) * 1970-03-21 1970-07-02 Record Appbau Gmbh Druckausgleichsgefaess.

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2032398A (en) * 1934-03-30 1936-03-03 Rca Corp Film drive mechanism
US2393324A (en) * 1942-09-18 1946-01-22 Joseph F Joy Automotive vehicle
US2482792A (en) * 1944-05-27 1949-09-27 Nasser D Owen Single-line hydraulic system

Cited By (13)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4785921A (en) * 1985-01-16 1988-11-22 Stabilus Gmbh Temperature-compensating hydraulic positioner
US4941542A (en) * 1986-10-01 1990-07-17 Mazda Motor Corporation Automotive four wheel steering system
US4982638A (en) * 1988-02-19 1991-01-08 Fried. Krupp Gesellschaft Mit Beschrankter Haftung Pneumatically operated cutting device
US4932197A (en) * 1988-12-28 1990-06-12 Allen David R Apparatus for positioning a work implement
US7634909B1 (en) * 2005-05-13 2009-12-22 Probir Chatterjea Articulated loader steering system
US20080210107A1 (en) * 2005-05-20 2008-09-04 Metso Paper, Inc. Actuator Means to Accomplish a Linear Movement
US7549370B2 (en) 2005-05-20 2009-06-23 Metso Paper, Inc. Actuator means to accomplish a linear movement
WO2006123014A1 (en) * 2005-05-20 2006-11-23 Metso Paper, Inc. An actuator means to accomplish a linear movement
WO2007006557A1 (de) 2005-07-11 2007-01-18 Laeis Gmbh Kolben-zylinder-anordnung
US7481161B2 (en) 2005-07-11 2009-01-27 Laeis Gmbh Plunger-cylinder assembly
FR2959782A1 (fr) * 2010-05-10 2011-11-11 Snecma Verin pour un circuit de fluide, tel par exemple qu'un circuit de carburant dans une turbomachine
WO2014127955A1 (de) * 2013-02-21 2014-08-28 Saf-Holland Gmbh Hydraulikeinheit
US10273732B2 (en) * 2016-05-23 2019-04-30 D&D Builders Hardware Co., Ltd. Lightly opening and bufferably closing door closer

Also Published As

Publication number Publication date
FR2203032B1 (enrdf_load_stackoverflow) 1978-02-17
DE2349392A1 (de) 1974-04-25
FR2203032A1 (enrdf_load_stackoverflow) 1974-05-10
JPS4972573A (enrdf_load_stackoverflow) 1974-07-12
NL7214004A (enrdf_load_stackoverflow) 1974-04-19
GB1448880A (en) 1976-09-08

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