WO1996026377A1 - Soupape a commande piezo-electrique - Google Patents

Soupape a commande piezo-electrique Download PDF

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Publication number
WO1996026377A1
WO1996026377A1 PCT/US1996/002201 US9602201W WO9626377A1 WO 1996026377 A1 WO1996026377 A1 WO 1996026377A1 US 9602201 W US9602201 W US 9602201W WO 9626377 A1 WO9626377 A1 WO 9626377A1
Authority
WO
WIPO (PCT)
Prior art keywords
actuator
piezo
seat
electric
housing
Prior art date
Application number
PCT/US1996/002201
Other languages
English (en)
Inventor
Dale A. Knutson
George R. Steber
Original Assignee
Applied Power Inc.
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
Priority claimed from US08/391,887 external-priority patent/US5593134A/en
Priority claimed from US08/392,016 external-priority patent/US5630440A/en
Application filed by Applied Power Inc. filed Critical Applied Power Inc.
Priority to AU48691/96A priority Critical patent/AU4869196A/en
Publication of WO1996026377A1 publication Critical patent/WO1996026377A1/fr

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Classifications

    • 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
    • F16K31/00—Actuating devices; Operating means; Releasing devices
    • F16K31/004—Actuating devices; Operating means; Releasing devices actuated by piezoelectric means
    • F16K31/005—Piezoelectric benders
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
    • F02M—SUPPLYING COMBUSTION ENGINES IN GENERAL WITH COMBUSTIBLE MIXTURES OR CONSTITUENTS THEREOF
    • F02M59/00—Pumps specially adapted for fuel-injection and not provided for in groups F02M39/00 -F02M57/00, e.g. rotary cylinder-block type of pumps
    • F02M59/44—Details, components parts, or accessories not provided for in, or of interest apart from, the apparatus of groups F02M59/02 - F02M59/42; Pumps having transducers, e.g. to measure displacement of pump rack or piston
    • F02M59/46—Valves
    • F02M59/466—Electrically operated valves, e.g. using electromagnetic or piezoelectric operating means
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
    • F02M—SUPPLYING COMBUSTION ENGINES IN GENERAL WITH COMBUSTIBLE MIXTURES OR CONSTITUENTS THEREOF
    • F02M59/00—Pumps specially adapted for fuel-injection and not provided for in groups F02M39/00 -F02M57/00, e.g. rotary cylinder-block type of pumps
    • F02M59/44—Details, components parts, or accessories not provided for in, or of interest apart from, the apparatus of groups F02M59/02 - F02M59/42; Pumps having transducers, e.g. to measure displacement of pump rack or piston
    • F02M59/46—Valves
    • F02M59/466—Electrically operated valves, e.g. using electromagnetic or piezoelectric operating means
    • F02M59/468—Electrically operated valves, e.g. using electromagnetic or piezoelectric operating means using piezoelectric operating means

Definitions

  • This invention relates to hydraulic or pneumatic valves, and in particular to such valves having piezo- electric actuators.
  • Solenoid operated pilot valves having a flapper- nozzle type electromagnetically operated actuator are known, for example, from U.S. Patent Nos. 4,774,976 and 5,328,147.
  • 4,774,976 has a nozzle type seat which is normally closed by a disk shaped armature or flapper.
  • a pulse width modulated signal or a proportional signal may be applied to a solenoid type electro-magnet positioned on the side of the armature opposite from the nozzle so as to variably open the nozzle.
  • the pressure exterior of the nozzle is typically higher than the pressure interior of the nozzle so that it biases the armature disk against the nozzle and a controlled pressure is produced downstream of the nozzle but upstream of an orifice which bleeds the excess flow to a relatively low tank pressure.
  • Valves such as those described in U.S. Patent No. 4,774,976 have found wide commercial application and work very well in many applications.
  • one limiting factor in the valve has been the requirement of the solenoid type electro-magnet for actuating the valve.
  • the solenoid adds significant cost to the valve, and is relatively large and heavy.
  • the base frequency of a pulse-width-modulated signal that can be used to operate the valve must be kept relatively low, for example 30-40 Hertz.
  • the resulting controlled pressure signal will display a dither of a corresponding frequency; at low pulse-width-modulated frequencies, the magnitude of the pressure dither is greater and may cause undesirable movements of the device being controlled by the valve.
  • the frequency response is dependent upon the pulse-width-modulated base frequency, the valve does not have a particularly fast frequency response and thus the band width of pressures which can be controlled is somewhat limited.
  • the solenoid be opposed from the nozzle, it is not possible to control two nozzles with a single armature.
  • Piezo-electric materials are also well known and have been used in a variety of applications. A material possesses piezo-electric properties if it produces an electric charge when it is subjected to a mechanical stress. When so subjected, a piezo-electric material exhibits what is known as the "generator effect" .
  • piezo-electric materials are naturally occurring crystalline materials such as quartz and tourmaline. Artificially produced piezo-electric crystals include rochelle salt, ammonium, dihydrogen phosphate (ADP) and lithium sulphate. Piezo-electric materials also include polarized piezo-electric ceramics. Piezo-electric ceramics include lead zirconate titanate, barium titanate, lead titanate and lead metaniobate.
  • the production process includes mixing the raw materials, heating the powders so as to react the constituents into a compound (known as "calcining") and grinding the calcined powders.
  • Various shapes may then be formed of the powders using a binder to hold the shapes together prior to firing. A number of firing steps may then occur to burn off the binders and provide mechanical strength, and at higher temperatures to chemically bond the material together. Electrodes are then applied to the desired surface or surfaces of the piezo-electric ceramic part.
  • the electrode may take the form of a layer of electrically conductive material such as silver oxide which is chemically deposited on the surface of the piezo-electric ceramic in a coating process, or may be an electrically conductive sheet such as invar, copper, nickel, brass or silver which is laminated to the surface of the piezo- electric ceramic.
  • the piezo-electric properties are activated in the manufacturing process when the part with the electrodes attached is subjected to a high electric field to align the dipoles within the ceramic material. This is sometimes done while the part is submerged in a heated dielectric bath. Aging of the ceramic then occurs in which the dipoles relax and eventually reach a steady state. Depolarization of the piezo-electric ceramic can result from excessive heat, electrical or mechanical stress or combinations of these conditions.
  • piezo-electric ceramics have found usage in many different applications. For example, piezo-electric ceramics are used in sonar and specialized transducers, in fish finders, in ultrasonic applications such as cleaners and other cavitation products, in high sensitivity hydrophones and other receiving devices, in accelerometers, and in electro-acoustic devices.
  • Piezo-electric ceramics have also been applied to actuate hydraulic valves.
  • hydraulic valve actuators thin sections of piezo-ceramic material have been stacked between multiple electrodes so as to produce a column of alternating layers of piezo material and electrode material. Individual voltages are then applie to the electrodes so that each layer of piezo-ceramic material changes slightly in thickness, but when all the changes in thickness add up due to the mechanical relationship of the piezo ceramic layers to one another, the total deflection of the column is sufficient to modulate the opening and closing of a hydraulic valve. While the force output is high and the displacement can be made sufficient, these types of actuators are bulky and expensive due to the volume of piezo ceramic materia required.
  • piezo-ceramic material to actuate a hydraulic valve, sometimes referred to as a "piezo bender"
  • a strip of piezo-ceramic material with a electrode laminated to one side is cantilevered at one end and at the opposite end overlies the seat of the hydraulic valve.
  • the strip can be caused to bend toward or away from the seat, depending upon the magnitude and polarity of the voltage applied across the piezo-ceramic material.
  • a variation on this is laminating two oppositely poled piezo strips to one another, rather tha one piezo strip to a metal electrode. Relatively large displacements (for example .010”) can be obtained, but the force output and the stiffness of the strips are ver low.
  • Thin sheets of piezo-electric ceramics laminated to an electrode sheet are known.
  • a layer of piezo- electric ceramic is laminated to only one side of the electrode sheet, the composite is known as a monomorph.
  • the electrode has a layer of piezo-electric ceramic material laminated on both of its sides, the resulting laminate is known as a bimorph.
  • a monomorph or bimorph deflects into a bowed shape if it is relatively long or wide or a cupped shape if it is both long and wide. The amount of deflection of a monomorph or bimorph depends upon the voltage applied, within limits.
  • the monomorph or bimorph When the voltage is oscillated, the monomorph or bimorph also oscillates, and can be oscillated at a relatively high frequency, for example 300 Hertz. Perhaps the most common application of monomorphs and bimorphs has been in acoustic devices, in which the monomorph or bimorph has been oscillated to produce a sound, much like the cone of a conventional speaker is oscillated to produce sounds. Such piezo composite actuators have also been applied to valves, for example, as shown in U.S. Patent Nos. 2,928,409, 3,063,422, 3,152,612, 3,524,474, 4,298,181, 4,535,810, 4,610,426, 4,705,059, 5,203,537 and 5,340,081.
  • a valve of the invention has a housing, an inlet port in the housing, an outlet port in the housing, and a nozzle type valve seat having an axis, an interior and an exterior, the interior being in communication with one of the ports and the exterior being in communication with the other of the ports, and with the seat lying in a first plane which is orthogonal to an axis of the seat.
  • a valve actuator is provided adjacent to the seat for varying an opening between the actuator and the seat for flow between the exterior and interior of the seat which includes a layer of piezo-electric material.
  • a single seat may be provided facing a surface of the actuator, or two opposed seats may be provided with the actuator between them and facing opposite surfaces of the actuator.
  • the actuator is in the shape of a sheet and is mounted in the housing generally parallel to the seat(s) at opposite edges of the actuator so that the housing constrains the edges against movement in the direction of the axis of the seat(s), with the piezo- electric layer of the actuator facing the seat.
  • the actuator when the actuator is electrically excited, it bows or cups relative to the seat(s), to vary the opening(s) of the valve.
  • This configuration provides a relatively small and low cost piezo-electric actuator in which the actuation forces and displacements obtainable are adequate to control relatively high pressure differentials and flow rates.
  • the actuator since the actuator has a fast frequency response, the pressure dither can be reduced by using a higher frequency pulse width modulated signal to control the valve, and the controlled pressure bandwidth is increased for any given frequency, as compared to a solenoid operated valve.
  • one seat is used in combination with an orifice downstream of the outlet port and opening to a relatively low pressure, simple and accurate pressure control can be achieved at the control port. If two seats are used on opposite sides of the actuator, two different outlet pressures can be provided which are inversely related to one another, for example to provide positive control over a spool position, or the two output pressures may be used independent of one another.
  • the flexibility of the actuator is increased for a given input level by providing a bent configuration at the ends of an electrode sheet of the actuator which extend beyond the piezo-electric layer of the actuator.
  • Each end has a leg portion which extends generally perpendicularly from the electrode sheet and an edge portion which extends generally perpendicularly from the leg portion, the edge portions being restrained in the housing.
  • the actuator can be made so that the piezo-electric layer has two or more sub-areas which are elecrically isolated from each other on one electrode surface.
  • One sub-area is used for deflecting the actuator, and the other subarea is used for feedback, since deflection of the actuator by the one sub-area causes the other sub-area to produce an electrical signal, as an indication of the deflection of the actuator.
  • FIG. 1 is a cross-sectional view of a piezo- electrically actuated hydraulic valve of the invention assembled in a valve block plumbed for controlling the position of the spool of a hydraulic valve spool, also shown;
  • Fig. 2 is a bottom plan view of a piezo-electric actuator for the valve of Fig. 1;
  • Fig. 3A is a side plan view of the piezo-electric actuator of Fig.2;
  • Fig. 3B is a side plan view of a second embodiment of a piezo-electric actuator for a valve of the invention
  • Fig. 3C is a side plan view of a third embodiment of a piezo-electric actuator for a valve of the invention
  • Fig. 4 is a bottom plan view of a forth embodiment of a piezo-electric actuator for a valve of the invention
  • Fig. 5 is a side plan view of the piezo-electric actuator of Fig. 4;
  • Fig. 6 is a bottom plan view of a fifth embodiment of a piezo-electric actuator of the invention.
  • Fig. 7 is a bottom plan view of a sixth embodiment of a piezo-electric actuator of the invention.
  • Fig. 8 is a bottom plan view of a seventh embodiment of a piezo-electric actuator of the invention.
  • Fig. 9 is a view similar to Fig. 1 of a second embodiment of a hydraulic valve of the invention.
  • Fig. 10 is a view of a modification to the embodiment of Fig. 9. Detailed Description of the Prefer**»H Ti ⁇ iV-odiments
  • a piezo-electrically actuated valve 10 of the invention includes a valve housing 12 which is made up of body 14, cap 16 and electrical connector 17.
  • the valve 10 also includes insert 18, which is pressed into the end of body 14 against a filte screen 19, and an orifice plate 21 which is trapped in the insert 18 by insert 23, which is pressed into the insert 18, and includes piezo-electric actuator 20.
  • the body 14 defines an inlet port 26, a relatively low pressure tank port 28 and a control pressure port 30.
  • the inlet port 26 is for receiving a pressurized flow of hydraulic oil from a suitable source such as a pump P, and communicating it through passageways 32 and 34 to th chamber 36 in which the actuator 20 resides.
  • Ends 20A and 20B of the actuator 20 are clamped between the cap 16 and the body 14.
  • An o-ring 38 seals the cap 16 to the body 14 and the cap 16 is crimped around its perimeter at 40 to secure it to the body 14.
  • Electrical connector 17 is secured to the cap 16 by bolts 41 and is sealed to the cap 16 by o-ring 17A.
  • Body 14 defines passageway 25 coaxial along axis 11 with nozzle type valve seat 27.
  • Body 14 also defines control port 30 which communicates with passageway 25 downstream of nozzle 27 and upstream of orifice plate 21, in which orifice 21A is formed.
  • the lumen of insert 23, downstream of orifice 21A, leads to tank port 28, which is in communication with a relatively low pressure tank pressure, denoted by tank T.
  • the orifice 21A is sized so as to create a restriction to the flow of fluid through it such that a desired pressure is produced in pressure port 30 when the nozzle 27 is open.
  • the pressure from port 30 is communicated via passageway 31 in valve block 29 to a chamber 33 at one end of a valve spool 35 which is slidable in bore 38 and has lands 37 and 39.
  • Springs 43 and 45 (the chamber in which spring 45 is located would normally be vented to tank pressure T, although not shown) serve to center the spool 35 with control land 37 blocking main control port 47, the chamber of the bore 38 between lands 37 and 39 being supplied with pressurized fluid from port 49.
  • the actuator 20 is a piezo-ceramic monomorph, which as illustrated (Figs. 1-3A) includes an electrode sheet 48 which is laminated on one of its sides to a layer 50, which is a sheet of piezo-ceramic material.
  • An electrically conductive coating 51, such as silver oxide is applied to the surface of sheet 50 which is opposite from electrode 48 and a lead wire 52 is soldered so as t establish electrical contact with the conductive coatin electrode 51.
  • a second lead wire 54 is soldered to the surface of electrode 48 which is opposite from piezo- ceramic sheet 50 so as to establish electrical contact with the electrode sheet 48.
  • An electrical potential is applied between the wires 52 and 54 so as to excite the piezo-ceramic sheet 50, which is in the field created between the coated electrode 51 and the sheet electrode 48.
  • Wires 52 and 54 exit the interior of the housing 12 in a fluid tight manner, being sealed by the connector
  • the piezo-ceramic sheet 50 is poled, preferably in the thickness direction, so that when it is excited with an electric field, the actuator 20 bows or cups in the direction indicated by arrow 56 in Fig. 3A.
  • Such monomorphs are available from EDO Corporation, Acoustics Division, of Salt Lake City, Utah.
  • the electrode sheet 48 was made of invar metal and had dimensions of 2" by 1" by approximately .008" thick.
  • Th piezo-ceramic sheet was EDO Corporation's EC-98 ceramic, which is a lead magnesium niobate composition, and had dimensions of 1.75" by 1" by .020" thick.
  • the actuator 20 Since the actuator 20 is assembled in the housing 12 with the piezo-ceramic sheet side facing the nozzle 27, a small area (for example 0.19" diameter) 58 of the coated electrode 51 is removed at the center of the actuator 20 and the nozzle 27 contacts the actuator 20 within this area. At least the electrode coating 51 must be removed in the area 58 or else, since the electrode 51 is positively charged when the actuator 20 is excited, an electrical short would be created between the electrode coating 51 and the nozzle 27. Alternatively, since the electrode sheet 48 is grounded, as is the nozzle 27, the electrode coating 51 and the piezo-ceramic sheet 50 may be removed in the area 58 and the electrode sheet 48 allowed to contact and seal against the nozzle 27.
  • the actuator 20 is clamped by the housing 12 along only its end edges 20A and 20B, which are the end edges of the electrode sheet 48.
  • the dotted line 64 in Fig. 2 identifies the shape defined by the sidewalls of the chamber 36 relative to the actuator 20 and there it can be seen that a space 66 and 68 exists between the respective side edges 20C and 20D of the actuator 20 and the sidewalls 64 of the chamber 36.
  • the spaces 66 and 68 allow hydraulic fluid entering the chamber 36 from the inlet port 26 to flow around the side edges 20C and 20D of the actuator 20 to the far side (or electrode sheet 48 side) of the actuator 20.
  • F A- . (P. - P 2 )
  • F the force
  • A. ⁇ is the cross-sectional area of the nozzle
  • P x is the pressure in the chamber 36 exterior of the nozzle 27
  • P 2 is the pressure interior of the nozzle 27.
  • the actuator 20 is quite brittle due to the brittleness of the piezo-ceramic sheet 50, it does have some resilient flexibility contributed by the electrode sheet 48 and its mounting in the housing 12.
  • the crimp 40 is formed so that the cap 16 exert a clamping load on the edges 20A and 2OB, the actuator 2 remains able to flex so as to bow or dish when it is electrically excited.
  • the height of the surfaces of the body 14 on which the ends 20A and 20B rest is machined such that the surface of the plane of the nozzle seat 27 in coincident with the plane of area 58 when the actuator 20 is mounte in the body with no electrical signal and no pressure applied.
  • a means of adjustment such as screw threads, shims or a friction fit could be provided to axially position the plane of the nozzle seat 27 in the same plane as area 58.
  • the actuator 20 may be excited by a pulse width modulated electrical signal or by a proportional voltage signal.
  • the voltages required are relatively high. For example, in the actuator described, a voltage of 500 volts is required to produce a center displacement (at axis 11 of nozzle 27) of approximately 0.010 inches.
  • the applied voltage is high, the piezo-ceramic actuator draws current only while the actuator is moving. Since the time of motion is usually less than 0.001 seconds, the average current consumption is relatively low compared to an equivalent solenoid. Because actuator 20 has a fast response, a relatively high frequency can be used for the pulse width modulated signal.
  • a relatively high frequency for modulating the actuator 20 (relative to the frequency which can be used with a solenoid operated valve) is desirable because it results in smoothing of the resulting pressure signal at the control port 30, i.e., the resulting pressure signal has less "dither" (or fluctuation) at the higher frequencies. Also, for a given pulse width modulated signal frequency, the pressure control band increases with faster valve actuation. While Fig. 3A illustrates an actuator 20 which is a monomorph, meaning that the electrode sheet 48 has only one side laminated to a piezo-ceramic sheet 50, Fig.
  • FIG. 3B illustrates an alternate embodiment of an actuator 120 which is a bimorph, in which electrode sheet 148 has each of its sides laminated to a separate piezo-ceramic sheet 150 and 153.
  • the actuator 120 is largely the same as the actuator 20, and the same reference numerals are applied to the actuator 120 as were applied to the actuator 20 for corresponding elements, plus 100.
  • an electrode coating 151 is applied to the outer surface of sheet 150 and an electrode coating 155 is applied to the outer surface of sheet 153.
  • Lead wire 152 is soldered so as to establish electrical contact with coating 151 and lead wire 157 is soldered so as to establish electrical contact with coating 155. Since the bimorph actuator 120 has ceramic sheets on both sides of the electrode sheet, a greater displacement would be possible for a given voltage if electrical potentials were applied to both ceramic sheets with appropriate poling so that they work together to simultaneously cause the actuator to bow in the same direction. Alternatively, with appropriate poling, an electrical potential could be applied to one of the ceramic sheets to cause the actuator to bow in one direction and an electrical potential could be applied to the other ceramic sheet to cause the actuator to bow in the other direction.
  • nozzle could then be adjusted relative to the actuator to produce an intermediate pressure at port 30 when no electric field is applied so that energizing one of the ceramic sheets would increase the pressure at port 30 and energizing the other sheet would reduce it. It may also be possible to accomplish this with a monomorph by simply reversing the polarity of the electrical field.
  • Fig. 3C illustrates a third alternate embodiment 2 which is essentially the same as the actuator 20, and corresponding reference numerals have been applied, plu 200.
  • the electrode 248 is extended a bent at its ends so as to define legs 261 and 263 which extend axially (relative to the axis 11 of the nozzle 27 and edges 220A and 220B, which are clamped between the body 14 and cap 16, are provided at the ends of legs 261 and 263 which are opposite from the main portion 265 of the electrode 248.
  • the edges 220A and 220B extend perpendicularly from the legs 261 and 263 and in plane which is generally parallel to the plane of the main portion 265 and of the piezo-ceramic sheet 250. This configuration provides for additional flexure of th electrode sheet 248 so that greater displacements may be achieved for a given voltage.
  • Figs. 4 and 5 illustrate another embodiment 420 of monomorph piezo-ceramic actuator for a valve of the invention.
  • Reference numerals have been applied to the embodiment 420 corresponding to the reference numerals o the actuator 20, plus 400.
  • the actuator 420 is the same as the actuator 20 except that the electrode coating has been divided into two sub-areas 451A and 5IB by perimetral zone 453 in which the electrode coating is etched away or masked in the coating process so that in the actuator 420 the coating is absent in this zone.
  • a third lead wire 449 is soldered so as to provide an electrical connection with the electrode coated sub-area 451B.
  • Coating sub-area 451B which is provided to act as a generator, does not electrically communicate with coating sub-area 451A.
  • lead 449 is provided as an output lead to monitor the voltage of sub- area 451B as an indication of the displacement of the actuator 420 and could be used as a feedback signal.
  • a piezo-ceramic actuator for a valve of the invention need not be rectangular in shape.
  • Figs. 6-8 show three embodiments of actuators 520, 620 and 720 having a circular peripheral shape.
  • reference numerals of the various elements have been applied corresponding to the reference numerals of the elements applied in the actuator 20, plus 500, 600, and 700, respectively.
  • the actuator 520 of Fig. 6, in the form of a thin disc, is most similar to the actuator 420 of Figs. 4 and 5, since the electrode coating on the ceramic layer 550 is divided into motor sub-area 551A and generator sub- area 551B by zones 553 in which the electrode coating is absent.
  • the zones 553 intersect nozzle contact area 558 in which the electrode coating is also absent.
  • the actuator 620 roughly approximates a rectangular actuator in which a circumferential rim of the electrode sheet 648 extends around the ceramic covered part of the electrode, which bridges the rim.
  • half moon shaped openings 678 and 680 are formed in the electrode sheet 648 and the piezo-ceramic sheet 650 is laminated to the center bridging portion of the electrode 648, which is between the openings 678 and 680.
  • An advantage of the embodiment 620 is that the openings 678 and 680 allow hydraulic fluid or gas to flow freely from one side of the actuator 20 to the other, whereas in the embodiments 520 and 720, if the edges of the electrode sheets 548 and 748 are clamped around all or substantially all of the periphery of the actuator, a separate passage must be provided in the housing to permit oil to flow from one side of the actuator to the other.
  • electrode sheet 748 is a disc
  • Fig. 9 illustrates an alternate embodiment of a pilot valve 810 of the invention.
  • elements corresponding to the elements illustrated in Fig. 1 are identified by the same reference numeral, plus 800, except respecting the actuator, which is the bimorph actuator 120.
  • valve 10 is operable to shift the spool 35 of a pilot operated hydraulic or gas valve in only one direction
  • the valve 810 can shift the spool 835 in either direction. This is accomplished essentially by replacing the actuator 20 with a bimorph actuator 120 such as that illustrated in Fig. 3B and replacing the cap 16 with auxiliary body 814' so as to provide nozzles on both sides of the actuator 120. Elements of the auxiliary body 814' corresponding to elements of the body 814 are identified by the same reference numeral, plus a prime (' ) sign.
  • the bodies 814 and 814' define nozzle type seats 827 and 827', one on each side of the actuator 120, and which lead to respective passageways 825 and 825' .
  • the passageways 825 and 825' branch into respective passageways 825A, 825B and 825A' , 825B' .
  • the respective passageways 825A and 825A' lead to control ports 830 and 830' which are connected by connectors 870, 870' to spool control passages 831, 831', respectively, which are formed in valve block 829 and communicate with closed chambers 833 and 833' at the ends of the spool 835.
  • Screw plugs 892, 892' and locknuts 894, 894' are provided to adjust the forces exerted on the spool 835 by the springs 843 and 845.
  • Bolts 841 and 841' secure the bodies 814 and 814' to the valve block 829 and bolts 872 secure the bodies 814 and 814' to each other.
  • Passageways 825B and 825B' provide communication with tank port 828 through respective orifices 821 and 821' (which are sealed to the respective bodies 814, 814' and to the valve block 829), passageways 876 and 876', annular passageways 878 and 878' which provide passage around end lands 839 and 837, and passageways 880 and 880' .
  • a relief valve RV is desirably provided (also for the pump P of Fig. 1) so as to relieve any excessive pressures which may be developed.
  • Supply port 849 communicates with chamber 36 through passageway 882, annular passageway 884 which provides passage around control land 841, passageway 886, connector 888 which is sealed between valve block 829 and body 814, and passageway 890.
  • Control land 841 regulates communication between annulus 884 and bore 838 to control the flow to control ports 847 and 851, and end lands regulate communication respectively between port 847 and relief annulus 878, and between port 851 and relief annulus 878' .
  • Passageway 880' is shown in dotted lines in ports 847, 849 and 851 to indicate that it does not intersect them.
  • a cylinder C is shown connected to control ports 847 and 851.
  • actuator 120 bows away from nozzle 827 and toward nozzle 827', which increases the pressure at control port 830 and reduces it at port 830' .
  • This has the effect of shifting spool 835, rightwardly to establish communication between ports 849 and 847 and between port 851 and relief port 828.
  • the piston of cylinder C is urged rightwardly as viewed in Fig. 9.
  • energizing piezo-ceramic sheet 153 bows actuator 120 away from nozzle 827' and toward nozzl 827, which increases the pressure at control port 830' relative to the pressure at control port 830, which shifts spool 835 leftwardly as viewed in Fig. 9, to establish communication between supply port 849 and control port 851 and between control port 847 and relief port 828. Accordingly, the piston of cylinder C moves leftwardly.
  • downstream orifices 821A, 821A' and 21A are fixed in size. However, in some applications it may be desirable to make the downstream orifices variable in size, and that this could be accomplished by removing them and routing the flow which would otherwise pass through each of them to an inlet port 26 of a valve 10 (or similar valve) so that each downstream orifice would be variable according to the operation of a piezo-electric actuator 20 of the corresponding valve.
  • Fig. 10 illustrates a modification to the valve 810, denominated 810', in which a pair of opposed nozzles 827 and 827' are combined with a monomorph actuator 20.
  • nozzle 827 is normally closed and nozzle 827' is normally open.
  • actuator 20 can be bowed upwardly against the nozzle 827' to close it and open nozzle 827. The effect of this, of course, would be to shift spool 835 rightwardly as viewed in Fig. 9. Deactuating layer 50 or reducing its excitation, shifts the spool 835 leftwardly.
  • valves in Figs. 9 and 10 are that positive pressures are used on both sides of spool 835 to control its position. This provides more stable control of the spool position may eliminate the need for springs 843 and 845 in some applications.
  • the invention provides a piezo-electrically actuated hydraulic valve particularly adapted as a pilot valve in which the actuator is smaller, lighter and less expensive than prior solenoid operated or piezo-operated actuators.
  • a valve of the invention has a piezo-electrically operated actuator with a fast frequency response, which may be used to control relatively high pressures over a relatively wider pressure control band and with a lower pressure dither amplitude.
  • a single actuator can be arranged to control a pair of nozzle seats. This can be applied in many different ways, for example to provide positive control over the position of a valve spool and/or to control spool position in both directions.

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  • Chemical & Material Sciences (AREA)
  • Combustion & Propulsion (AREA)
  • Electrically Driven Valve-Operating Means (AREA)

Abstract

Une soupape hydraulique (10) à commande piézo-électrique présente un siège (27) de type buse, un actuateur piézo-électrique (20) dans un plan orthogonal à l'axe de la buse (27), un orifice (21A) dans une ouverture basse pression (28) en aval du siège (27), et une ouverture de pression de commande (30) entre le siège (27) et l'orifice (21A). L'actuateur (20) comprend une touche piézo-céramique (50) stratifiée sur une plaque d'électrode (48) de sorte que le composite prenne la forme d'une plaque avec une surface (51) de la couche piézo-céramique (50) tournée vers le siège (27). La plaque d'électrode (48) présente des bords opposés (20A, 20B) s'étendant au-delà de ladite couche piézo-céramique (50), et serrés par le logement (12) de la soupape de sorte que le centre de l'actuateur (20) soit positionné sur le siège (27). Lorsqu'un champ électrique est appliqué à la couche piézo-céramique (50), l'actuateur (20) se courbe ou s'évase afin de se déplacer par rapport à la buse (27) de manière à faire varier la surface d'écoulement entre le siège (27) et l'actuateur (20). On peut utiliser des actuateurs monomorphes (20) ou bimorphes (120), et on peut prévoir une seule buse (27) sur un seul côté de l'actuateur, ou une paire de buses opposées (827, 827') peut être ménagée avec l'actuateur entre celles-ci et normalement assis contre une des deux. Les extrémités (220A, 220B) de la plaque d'électrode (248) sont courbées afin d'augmenter la déflexion de l'actuateur (220) pour une certaine tension d'entrée. Des sous-surfaces (451A, 451B) sont ménagées sur la couche piézo-céramique (450) afin de produire un signal de retour électrique lorsque l'actuateur est défléchi piézo-électriquement.
PCT/US1996/002201 1995-02-21 1996-02-20 Soupape a commande piezo-electrique WO1996026377A1 (fr)

Priority Applications (1)

Application Number Priority Date Filing Date Title
AU48691/96A AU4869196A (en) 1995-02-21 1996-02-20 Piezo-electrically actuated valve

Applications Claiming Priority (6)

Application Number Priority Date Filing Date Title
US39197295A 1995-02-21 1995-02-21
US08/392,016 1995-02-21
US08/391,887 1995-02-21
US08/391,972 1995-02-21
US08/391,887 US5593134A (en) 1995-02-21 1995-02-21 Magnetically assisted piezo-electric valve actuator
US08/392,016 US5630440A (en) 1995-02-21 1995-02-21 Piezo composite sheet actuated valve

Publications (1)

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WO1996026377A1 true WO1996026377A1 (fr) 1996-08-29

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PCT/US1996/002201 WO1996026377A1 (fr) 1995-02-21 1996-02-20 Soupape a commande piezo-electrique
PCT/US1996/002235 WO1996026378A1 (fr) 1995-02-21 1996-02-20 Actuateur de soupape piezo-electrique a assistance magnetique

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PCT/US1996/002235 WO1996026378A1 (fr) 1995-02-21 1996-02-20 Actuateur de soupape piezo-electrique a assistance magnetique

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Cited By (3)

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Publication number Priority date Publication date Assignee Title
WO1998022727A1 (fr) * 1996-11-21 1998-05-28 Advanced Fluid Systems Limited Soupape de regulation de debit et amortisseur
EP0960364A2 (fr) * 1997-02-11 1999-12-01 Engineering Measurements Company Appareil et procede de regulation de tres faible debit massique
FR2815215A1 (fr) * 2000-10-05 2002-04-12 Cit Alcatel Terminal apte a etre alimente localement et a etre telealimente par une liaison le reliant a un reseau local

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Publication number Priority date Publication date Assignee Title
DE29722085U1 (de) * 1997-12-13 1998-02-26 Festo AG & Co, 73734 Esslingen Ventil

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EP0046431A1 (fr) * 1980-08-19 1982-02-24 Societe D'optique, Precision Electronique Et Mecanique - Sopelem Servo-valve électro-hydraulique
EP0404082A2 (fr) * 1989-06-22 1990-12-27 Hoechst CeramTec Aktiengesellschaft Transducteur de pliage piézoélectrique et son utilisation
JPH04362302A (ja) * 1991-06-07 1992-12-15 Res Dev Corp Of Japan サーボ弁の制御機構
EP0544405A1 (fr) * 1991-10-25 1993-06-02 The Technology Partnership Limited Vanne de régulation de débit à commande piézoélectrique

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FR2540962B1 (fr) * 1983-02-14 1986-01-10 Mecilec Sa Electrovalves a commande piezoelectrique
JPS61167364A (ja) * 1985-01-18 1986-07-29 Diesel Kiki Co Ltd 高速電磁弁
AU5992286A (en) * 1985-06-11 1987-01-07 Arthur D. Little, Inc. Apparatus for electrical control of rate of fluid flow

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Publication number Priority date Publication date Assignee Title
EP0046431A1 (fr) * 1980-08-19 1982-02-24 Societe D'optique, Precision Electronique Et Mecanique - Sopelem Servo-valve électro-hydraulique
EP0404082A2 (fr) * 1989-06-22 1990-12-27 Hoechst CeramTec Aktiengesellschaft Transducteur de pliage piézoélectrique et son utilisation
JPH04362302A (ja) * 1991-06-07 1992-12-15 Res Dev Corp Of Japan サーボ弁の制御機構
EP0544405A1 (fr) * 1991-10-25 1993-06-02 The Technology Partnership Limited Vanne de régulation de débit à commande piézoélectrique

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PATENT ABSTRACTS OF JAPAN vol. 17, no. 233 (M - )<1407> 12 May 1993 (1993-05-12) *

Cited By (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO1998022727A1 (fr) * 1996-11-21 1998-05-28 Advanced Fluid Systems Limited Soupape de regulation de debit et amortisseur
US6352144B1 (en) 1996-11-21 2002-03-05 Advanced Fluid Systems Limited Flow-control valve and damper
EP0960364A2 (fr) * 1997-02-11 1999-12-01 Engineering Measurements Company Appareil et procede de regulation de tres faible debit massique
JP2001513922A (ja) * 1997-02-11 2001-09-04 エンジニアリング メジャメンツ カンパニー 微小質量流量制御装置および方法
EP0960364A4 (fr) * 1997-02-11 2004-09-01 Engineering Measurements Co Appareil et procede de regulation de tres faible debit massique
FR2815215A1 (fr) * 2000-10-05 2002-04-12 Cit Alcatel Terminal apte a etre alimente localement et a etre telealimente par une liaison le reliant a un reseau local
US6603220B2 (en) * 2000-10-05 2003-08-05 Alcatel Terminal adapted to be powered locally and to receive a remote power feed via a link connecting it to a local area network

Also Published As

Publication number Publication date
WO1996026378A1 (fr) 1996-08-29
AU4869196A (en) 1996-09-11
AU4928196A (en) 1996-09-11

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