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
  • F16K27/00—Construction of housing; Use of materials therefor
  • F16K27/04—Construction of housing; Use of materials therefor of sliding valves
  • F16K27/041—Construction of housing; Use of materials therefor of sliding valves cylindrical slide 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
  • F15B13/02—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
  • 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
  • F16K11/0716—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 with fluid passages through the valve member

Definitions

• This invention relates to fluid " control device such as hydraulic or pneumatic controls-valves, servovalv and position control devices and in particular relates to such devices of the sliding spool type which are pilot operated to facilitate better response, control of large flow capacities and/or control from remote controlling means.
• the remote controlling means may be mechanical, electromechanical, electrohydraulic, fluidic or electroni or any combination-thereo , be it proportional control, analogue, digital, mark/space ratio or otherwise.
• pilot valve is also of the spool type as the same criticality of tolerances applies to the pilot valve.
• Other types of pilot valves such as slide valves, flapper valves, nozzle-jets or variations of each are well known and have various different charac- teristics which render them suitable in some situations and not in others.
• the fine tolerances required with these other types of pilot valves requires at least the same high degree of accuracy in manufacture as with spool type valves and thus' there are no real gains to be made from a cost consideration as between the various alternatives. The choice thus usually depends on the particular requirements of the control ⁇ " be it on-off control, proportional control or servo-control, for example, and whatever the choice the cost of such control is -relatively expensive.
• the object of this invention is to provide an improved control arrangement for a spool type control valve which is more economical to manufacture than existing arrangements. It is a further object to provide.an improved control arrangement for a spool type control valve which facilitates on-off, proportional and/or servo-control of a fluid medium. It should be noted that these latter two types of control'are not conveniently achievable with spool type pilot valves.
• the invention provides a fluid control device of the sliding spool type wherein a spool having various lands is adapted to slide within the bore of a body part to facilitate primary fluid flow between various main ports in said body part dependent upon the position of said spool, said spool having a longitudinal bore extending therethrough and means within said spool bore to facilitate fluid controlled movement of said spool, characterized in that, said means comprises a con- trol profile having radial clearance in said spool bore and separating respective control chambers, each control chamber includes part of the bore of said body part whereby pressurized fluid in said control chambers exerts forces or respective endsof said spool, a first or arrangement is provided in said spool to facilitate second ary fluid flow from a pressure port of said main ports, through the wall of said spool and onto said control profile whereby said secondary flow is directed into respective said control chambers and, via further respec- tive orifice arrangements, back to -the low pressure side of a fluid supply such that said device is caused
• FIG. 1 is a sectional side elevation of the hydraulic control valve taken in a . longitudinal direction through the valv body
• FIG. 2 is a part sectional view taken on the lines A-A of FIG. 1
• FIG. 3 is a part sectional view similar to
• FIG. 1 showing fluid pressures and flo with the control element in the neutral position
• FIG. 4 is similar to FIG. 3 showing the fluid pressures and forces acting on the spoo when the 'control element is in the neut position
• FIG. 5 is similar to FIGS. 3 and 4 showing the fluid pressures and forces acting on th spool when the control element is displ from the neutral position.
• the control valve consists essentially of a valve bo 2 and a control spool 4 which slides within a central bor through the body 2.
• the control spool 4 has a series of lands around the outer surface thereof and a central bore 3 which extends longitudinally through the spool.
• Five ports are arranged in the body 2 and communicate with various chambers which surround ' the spool. These ports comprise a pressure port 10, two tank ports 16 and outlet ports 35 and 37.
• the control valve as described to date is essentially the same as any number of conventional directional control valves and servo valves.
• the valve body 2 has respective end plates 28,3 which seal the respective ends of the central bore of the valve body and a control rod 18 passes through a suitable aperture in each end plate 28,30 and is sealed therein by a suitable"O"ring 32 at each end plate.
• the control spoo 4 has an orifice 5 extending through the wall thereof on both sides of the central bore 3.
• the orifice 5 is arran midway between the ends of the control spool 4.
• Identica orifices 6 and 8 are arranged towards respective ends of the control spool 4.
• Each orifice 6 and 8 extends throug the wall of the control spool 4 on opposite sides of the central bore 3.
• the orifices 6 and 8 are smaller in diameter than the orifice 5 and all three exte radially.
• the orifice 5 is termed an inlet control orifice and the orifices 6 and 8 are termed outle control orifices.
• the inlet control orifice 5 connects at all times -to pressure port 10 and each outlet control orifice 6 and 8 communicate with respective tank ports 16 at all times.
• the inlet control orifice 5 and " the outlet control orifices 6 and 8 thus provide a continuous flow o hydraulic fluid into, and out of, the respective control chambers 12 and 14 within the central bore 3 of the spool 4.
• the control chambers 12 and 14 are separated by a control profile 20 located on the control rod 18 and form integrally therewith or suitably attached thereto.
• a radial clearance 22 exists between the contro profile 20 and the internal surface of central bore 3 of the control spool 4.
• the clearance 22 allows continual secondary flow of fluid from the pressure port 10 through - the inlet orifice 5 to control chambers 12 and 14 respect and finally through each outlet control orifice 6,8 to th tank ports 16. '
• Pressure P acts at all times on face 24 of the control spool 4 and pressure P acts at all times on face 26 of the spool 4.
• the control spool 4 is at rest within body 2, the pressures P, and P ⁇ and any flow forces are equilibrium.
• the equilibrium is upset by changes i pressures P, and P ⁇ or -flow forces, the control spool 4 will move to restore the equilibrium.
• the resistance to secondary fluid flow due to the shape of the control profile 20 and the shape and position of the orifices 5, 6 and 8 causes the valve to act as .a hydraulic Wheatston bridge tending always towards equilibrium.
• Control input to the control rod 18 is provid by a suitable externally mounted transducer 34, which ma take any of various known formssuch as manual, mechanica electromechanical, electrohydraulic, electronic, fluidic or a combination thereof.
• the device operates as follows. High pressure fluid is supplied to pressure port 10 and flows through the inlet control orifice 5 to the control chamb 12 and 14 on respective sides of the control profile 20. The fluid then flows through the outlet control orifices 6 and 8 to the tank ports 16. Due to the small size of the orifices 5, 6 and 8, in comparison with the main passages of the control valve, the fluid flow rates thro the control chambers 12 and 14 are only a fraction of- th fluid flow rates through the control valve main ports 35, 37, 10 and 16.
• control profile 2 is shown displaced in relation to the orifice 5.
• the resistance to flow into chamber 12 is larger than the resistance to flow into chamber 14 and thus pressure P, in control chamber 12 is less than pressure P réelle in control chamber 14.
• the force 2 acting on the control spool 4 due to pressure P_ is thus larger than force f, due to pressure P, and the control spool 4 will therefore move to a position whereby the orifice 5 is centrally located relative to the control profile 20. In other words, the control spool 4 will move to re-establish equilibrium of forces f, and f- and equilibrium of the flow forces.
• the speed of response of the control spool 4 to the positional change of control rod 18 and thus the position of control profile 20, is a function of the sizes of the r arious orifices and the shape of the control ' profile 20.
• the fluid control device according to the present invention provides an improved arrangement which allows the operation of large flow capacity valves which require considerable force to shift the controlled member (control spool) .
• the device according to this invention is convenient to manufacture because fihere are no critic tolerances as between the control profile 20 and the inn surface of the bore through the control spool 4. Moveme of the control rod 18 does not require a significant for in relation to the forces required to move the control spool 4 and thus the rod may be moved by any convenient transducer means 34 adapted to provide the necessary control to operate the spool 4 in the manner required.
• the valve has a high gain force feedback
• the control spool 4 has various land.s which are arranged in relation to the inlet and outlet ports to provide whatever necessary control is required at some remote machine location.
• the invention thus provides a low cos and simple two stage operation of valves and position control devices and eliminates the conventional pilot spool controls with their inherent disadvantages.
• the control valve described provides a- 1:1 ratio position feedback and can be readily adapted to provide on-off control, proportional control and/or servo control as required.
• the valve described may be conveniently adapted for continuous control in an automat manner such that continuous control of proportion control valves, servo valves and position control devices is readily attainable.
• the orifices 5, 6 and 8 may in fact compr a series of radially disposed orifices in order to achiev a particular fluid flow.
• outlet control orifi 6 and 8 are arranged in the valve body 2 rather than in wall of the spool 4 and thus connect the chambers 12 and 14 directly with the low pressure side of the hydraulic supply.
• the control orifices 6 an 8 may be made adjustable " in size externally of the body part whereby the characteristics of the control valve, s as a response time for example, may be readily adjusted.
• the control spool 4 is directly connected to operate external machinery.
• the control valve instead of the control valve being used to operate equipment such as a hydraulic ram, for example, which in turn actuates some mechanical move- ment, the control valve may, in some circumstances, be us to directly actuate the mechanical movement.
• control profi 20 which is shown in the described embodiment as being symmetrical in the longitudinal direction about a central transverse plane may, according to a modification, be asymmetrical in order to provide different characteristic for the opposite directions of movement of the control spool 4.
• the different characteristics may relate to response time or force, for example.

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• Engineering & Computer Science (AREA)
• General Engineering & Computer Science (AREA)
• Mechanical Engineering (AREA)
• Physics & Mathematics (AREA)
• Fluid Mechanics (AREA)
• Servomotors (AREA)
• Sliding Valves (AREA)

Applications Claiming Priority (2)

Publications (2)

Family

ID=3769421

Family Applications (1)

Country Status (3)

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Citations (4)

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• 1983
  • 1983-03-24 JP JP50154083A patent/JPS59500481A/ja active Pending
  • 1983-03-24 WO PCT/AU1983/000036 patent/WO1983003455A1/en not_active Application Discontinuation
  • 1983-03-24 EP EP19830901307 patent/EP0105895A4/de not_active Withdrawn

Patent Citations (4)

Non-Patent Citations (1)

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