US3342213A - Hydraulic apparatus - Google Patents

Hydraulic apparatus Download PDF

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Publication number
US3342213A
US3342213A US473413A US47341365A US3342213A US 3342213 A US3342213 A US 3342213A US 473413 A US473413 A US 473413A US 47341365 A US47341365 A US 47341365A US 3342213 A US3342213 A US 3342213A
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US
United States
Prior art keywords
valve
spool
ports
hydraulic
lands
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
US473413A
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English (en)
Inventor
Walters Ronald
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.)
Sperry Gyroscope Co Ltd
Original Assignee
Sperry Gyroscope Co 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 Gyroscope Co Ltd filed Critical Sperry Gyroscope Co Ltd
Application granted granted Critical
Publication of US3342213A publication Critical patent/US3342213A/en
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Expired - Lifetime legal-status Critical Current

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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
    • 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
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
    • F16K—VALVES; TAPS; COCKS; ACTUATING-FLOATS; DEVICES FOR VENTING OR AERATING
    • F16K11/00—Multiple-way valves, e.g. mixing valves; Pipe fittings incorporating such valves
    • F16K11/02—Multiple-way valves, e.g. mixing valves; Pipe fittings incorporating such valves with all movable sealing faces moving as one unit
    • F16K11/06—Multiple-way valves, e.g. mixing valves; Pipe fittings incorporating such valves with all movable sealing faces moving as one unit comprising only sliding valves, i.e. sliding closure elements
    • F16K11/065—Multiple-way valves, e.g. mixing valves; Pipe fittings incorporating such valves with all movable sealing faces moving as one unit comprising only sliding valves, i.e. sliding closure elements with linearly sliding closure members
    • F16K11/07—Multiple-way valves, e.g. mixing valves; Pipe fittings incorporating such valves with all movable sealing faces moving as one unit comprising only sliding valves, i.e. sliding closure elements with linearly sliding closure members with cylindrical slides
    • 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
    • Y10T137/8667—Reciprocating valve
    • Y10T137/86694—Piston valve
    • Y10T137/8671—With annular passage [e.g., spool]
    • 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
    • Y10T137/86718—Dividing into parallel flow paths with recombining
    • Y10T137/86734—With metering feature

Definitions

  • the invention relates to hydraulic servo systems and in particular to spool valves for use in such systems.
  • a spool valve in which the spool has raised lands co-operating with ports drilled in the walls of the valve body, or in a sleeve forming a lining for the valve body.
  • the arrangement of the lands and ports is such that in the neutral position of the valve the ports are closed by the lands, and a small displacement of the valve spool in one or the other sense allows a flow of hydraulic fluid in one or the other direction through the actuator.
  • the ports are normally circular in section, and in order to obtain a linear relation between the spool displacement and hydraulic flow the lands are sometimes made to underlap the valve ports, that is to say they are slightly narrower in width than the diameter of the ports. This results in the valve having a slight hydraulic leakage in its neutral position, but usually this is of no importance.
  • the hydraulic gain of the valve that is to say the flow per unit displacement of the spool, is inversely related to the gain of the other parts of the servo loop, which are usually electrical, since the overall gain is a design factor determined by requirements of stability and dynamic response of the system.
  • the electrical gain in an electro-hydraulic servo system usually controls the steady-state errors of the system and therefore, for accuracy of position, for example, in a hydraulic positioning system, the electrical gain should be as high as possible, the hydraulic gain being correspondingly low.
  • the rapidity of response to larger error signals is determined by the flow through the valve, and for these larger signals it is an advantage for the hydraulic gain to be high and the electrical gain correspondingly low.
  • An object of the present invention is to provide a form of hydraulic valve of convenient construction and non-linear response, and a servo system incorporating such a valve.
  • each set of metering ports for the hydraulic fluid comprises at least one port of circular section and of a diameter slightly exceeding the width of the spool lands, and at least one port of circular section and of a diameter less than that of the spool lands.
  • the invention is applicable in particular to electrohydraulic valves in which the valve spool is driven by a torque motor either directly or through a pilot stage and the electrical drive circuits may include an amplifier having a non-linear response such as to compensate for the characteristic of the valve and maintain a substantially constant open loop gain for the system as a whole.
  • the electrical drive circuits may include an amplifier having a non-linear response such as to compensate for the characteristic of the valve and maintain a substantially constant open loop gain for the system as a whole.
  • 3342,213 Patented Sept. 19, 1967 two sizes of valve port will be suflicient for most applications, but the number of ports of each size may be varied according to the particular characteristic required.
  • FIGURE 1 is a sectional view of a hydraulic portion of an electro-hydraulic servo valve according to the invention.
  • FIGURE 2 is a schematic development of one set of ports responsible for the metering of the flow of output fluid.
  • the valve consists of a valve body 1 within which is shrink-fitted a central sleeve 2 in which the valve ports of the main valve are drilled and having passages for the supply to them of hydraulic fluid.
  • a spool 3 of the main valve Within the sleeve 2 is a spool 3 of the main valve, having a pair of raised lands 4 and 5 which respectively cooperate with sets of ports 6 and 7 formed in the sleeve.
  • Hydraulic fluid under pressure is supplied through a passageway 8 to the space between the lands of the spool and is exhausted to a tank at low pressure from spaces 9 and 10 outside the lands, the lands 4 and 5 co-operating with the sets of ports 6 and 7 meter the flow of fluid to a hydraulic jack or motor, displacement of the valve spool allowing fluid under pressure to pass into one set of ports, and fluid returned from the jack or motor to pass to the tank from the other.
  • this part of the valve is conventional in structure.
  • the ports 6 and 7 are arranged as shown in the development of FIG. 2.
  • the ports consist of a pair of orifices 14, 15 whose diameter exceeds the width of the face of the valve land 16 by a few ten thousandths to a few thousandths of an inch according to the size of the valve.
  • In between these larger ports 14, 15 are two series each of three smaller orifices 17, 18, 19 of uniform size and having their axes all in the same plane, but all of somewhat smaller diameter than the width of the spool land 16
  • the valve shown is of a two-stage type in which the spool is bored at one end to receive a sleeve 11 Within which works a smaller spool 12 forming a second pilot valve arranged within the main spool.
  • the other end of the main valve spool is bored to receive a compensating piston 13 the inner end of which is exposed to the main hydraulic pressure.
  • the outer end of this piston bears against an abutment (not shown in the drawing) when the valve is assembled in place
  • the space between the spool 3 and the main sleeve 2 is closed by a flanged ring 20 having ports for hydraulic fluid, and the spool 3 also has a further raised land 21, the space between the land 21 and the end of the ring 20 forming a further hydraulic cylinder to which fluid can be admitted through ports under the control of the pilot valve spool 12.
  • the area of this annular cylinder is arranged to be twice that of the cross section of the compensating piston 13.
  • a torque motor (not shown) is used to move the pilot valve spool 12 in response to an electrical input signal.
  • the pilot valve spool 12 When the pilot valve spool 12 is in its neutral position, the pressure in the annular space between the ring 20 and the land 21 is half that of the hydraulic supply and is just counterbalanced by the supply pressure acting on the compensating piston 13, which is of half the crosssectional area.
  • the small orifices 17, 18, 19 of FIGURE 2 are not uncovered, and the larger orifices 14 and 15 are operating in the normal manner with a slight underlap giving a linear variation of flow rate. If the displacement increases further, the edges of the smaller orifices 17, 18, 19 become uncovered by the lands 4 and 5, giving a further increase in flow rate.
  • valve designed for use at a pressure of 3000 lbs. to the square inch and a maximum flow rate of 40 gallons per minute
  • the bore of the valve body was 1.5 inches
  • the valve was provided with two rings of ports each consisting of four holes 0.104" diameter and twelve holes 0.094" diameter with their axes in the central planes of the lands in the valve neutral position.
  • the ratio of the gain at maximum valve travel to that at valve neutral was 6:6.
  • each ring of ports consisted of two holes of the larger size and twenty-two of the smaller. This valve had a gain ratio of 19:6.
  • the servo valve is arranged to 'be driven by an electrical circuit incorporating either a non-linear amplifier or a non-linear correction means which compensates for the change in hydraulic gain of the valve with displacement and so maintains the open loop gain of the system substantially constant.
  • the linear characteristic of the valve is obtained by the use only of circular orifices which can be formed by known methods accurately and reproducibly.
  • a hydraulic spool valve comprising a body, a plurality of sets of metering ports for hydraulic fluid in the walls of said valve body, a spool within said valve body, said spool having raised lands for cooperating with said ports, in which each set of metering ports for the hydraulic fluid comprises at least one port of circular section and of a diameter slightly exceeding the width of the spool lands, and at least one port of circular section and of a diameter less than that of the spool lands.
  • each set of ports comprises at least two ports of each size symmetrically disposed about the spool axis so as to avoid unbalanced radial forces on the spool.
  • a hydraulic spool valve according to claim 2 in which the said ports are of two sizes.

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  • Engineering & Computer Science (AREA)
  • General Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • Physics & Mathematics (AREA)
  • Fluid Mechanics (AREA)
  • Sliding Valves (AREA)
  • Servomotors (AREA)
US473413A 1964-07-22 1965-07-20 Hydraulic apparatus Expired - Lifetime US3342213A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
GB2956964 1964-07-22

Publications (1)

Publication Number Publication Date
US3342213A true US3342213A (en) 1967-09-19

Family

ID=10293594

Family Applications (1)

Application Number Title Priority Date Filing Date
US473413A Expired - Lifetime US3342213A (en) 1964-07-22 1965-07-20 Hydraulic apparatus

Country Status (3)

Country Link
US (1) US3342213A (de)
DE (1) DE1500239C3 (de)
SE (1) SE312704B (de)

Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3952775A (en) * 1975-03-14 1976-04-27 Shoketsu Kinzoku Kogyo Kabushiki Kaisha Electromagnetic change-over valve
US4182375A (en) * 1978-05-13 1980-01-08 Shoketsu Kinzoku Kogyo Kabushiki Kaisha Spool-sleeve type change-over valve
US20120104293A1 (en) * 2009-03-31 2012-05-03 Walter Fleischer Pressure control valve, in particular for an automatic transmission in a motor vehicle
US11428331B2 (en) * 2019-09-09 2022-08-30 Smc Corporation Servo valve

Families Citing this family (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3451557A (en) * 1967-04-12 1969-06-24 Gen Electric Removable article supporting device for automatic dishwasher rack
JPS5655483Y2 (de) * 1976-05-17 1981-12-24
EP0076664A1 (de) * 1981-10-02 1983-04-13 J.H. Fenner & Co. Limited Steuerung von Druckluftmotoren
GB201420289D0 (en) * 2014-11-14 2014-12-31 Blagdon Actuation Res Ltd Improvements in and relating to servo valves

Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2696196A (en) * 1949-02-18 1954-12-07 Denison Eng Co Control valve for hydraulic apparatus
US2798461A (en) * 1953-06-10 1957-07-09 Gen Motors Corp Fluid power steering control valve
US2872943A (en) * 1954-06-02 1959-02-10 Dravo Corp Spring balanced fluid pressure control valve

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2696196A (en) * 1949-02-18 1954-12-07 Denison Eng Co Control valve for hydraulic apparatus
US2798461A (en) * 1953-06-10 1957-07-09 Gen Motors Corp Fluid power steering control valve
US2872943A (en) * 1954-06-02 1959-02-10 Dravo Corp Spring balanced fluid pressure control valve

Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3952775A (en) * 1975-03-14 1976-04-27 Shoketsu Kinzoku Kogyo Kabushiki Kaisha Electromagnetic change-over valve
US4182375A (en) * 1978-05-13 1980-01-08 Shoketsu Kinzoku Kogyo Kabushiki Kaisha Spool-sleeve type change-over valve
US20120104293A1 (en) * 2009-03-31 2012-05-03 Walter Fleischer Pressure control valve, in particular for an automatic transmission in a motor vehicle
US11428331B2 (en) * 2019-09-09 2022-08-30 Smc Corporation Servo valve

Also Published As

Publication number Publication date
SE312704B (de) 1969-07-21
DE1500239C3 (de) 1975-11-27
DE1500239A1 (de) 1969-04-30
DE1500239B2 (de) 1975-04-10

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