US3734129A - Hydraulic control valve - Google Patents
Hydraulic control valve Download PDFInfo
- Publication number
- US3734129A US3734129A US00145355A US3734129DA US3734129A US 3734129 A US3734129 A US 3734129A US 00145355 A US00145355 A US 00145355A US 3734129D A US3734129D A US 3734129DA US 3734129 A US3734129 A US 3734129A
- Authority
- US
- United States
- Prior art keywords
- valve
- poppet
- spool
- port
- pressure
- 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
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Classifications
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- 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
-
- 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
- F15B11/00—Servomotor systems without provision for follow-up action; Circuits therefor
- F15B11/02—Systems essentially incorporating special features for controlling the speed or actuating force of an output member
- F15B11/04—Systems essentially incorporating special features for controlling the speed or actuating force of an output member for controlling the speed
-
- 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
- F15B11/00—Servomotor systems without provision for follow-up action; Circuits therefor
- F15B11/16—Servomotor systems without provision for follow-up action; Circuits therefor with two or more servomotors
-
- 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
-
- 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
- F15B13/02—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
- F15B13/0405—Valve members; Fluid interconnections therefor for seat valves, i.e. poppet 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
- F15B2211/00—Circuits for servomotor systems
- F15B2211/20—Fluid pressure source, e.g. accumulator or variable axial piston pump
- F15B2211/205—Systems with pumps
- F15B2211/2053—Type of pump
- F15B2211/20538—Type of pump constant capacity
-
- 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
- F15B2211/00—Circuits for servomotor systems
- F15B2211/30—Directional control
- F15B2211/305—Directional control characterised by the type of valves
- F15B2211/30525—Directional control valves, e.g. 4/3-directional control valve
-
- 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
- F15B2211/00—Circuits for servomotor systems
- F15B2211/30—Directional control
- F15B2211/305—Directional control characterised by the type of valves
- F15B2211/3056—Assemblies of multiple valves
- F15B2211/30565—Assemblies of multiple valves having multiple valves for a single output member, e.g. for creating higher valve function by use of multiple valves like two 2/2-valves replacing a 5/3-valve
-
- 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
- F15B2211/00—Circuits for servomotor systems
- F15B2211/30—Directional control
- F15B2211/32—Directional control characterised by the type of actuation
- F15B2211/321—Directional control characterised by the type of actuation mechanically
- F15B2211/324—Directional control characterised by the type of actuation mechanically manually, e.g. by using a lever or pedal
-
- 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
- F15B2211/00—Circuits for servomotor systems
- F15B2211/30—Directional control
- F15B2211/35—Directional control combined with flow control
- F15B2211/351—Flow control by regulating means in feed line, i.e. meter-in control
-
- 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
- F15B2211/00—Circuits for servomotor systems
- F15B2211/30—Directional control
- F15B2211/35—Directional control combined with flow control
- F15B2211/353—Flow control by regulating means in return line, i.e. meter-out control
-
- 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
- F15B2211/00—Circuits for servomotor systems
- F15B2211/50—Pressure control
- F15B2211/505—Pressure control characterised by the type of pressure control means
- F15B2211/50509—Pressure control characterised by the type of pressure control means the pressure control means controlling a pressure upstream of the pressure control means
- F15B2211/50518—Pressure control characterised by the type of pressure control means the pressure control means controlling a pressure upstream of the pressure control means using pressure relief 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
- F15B2211/00—Circuits for servomotor systems
- F15B2211/50—Pressure control
- F15B2211/55—Pressure control for limiting a pressure up to a maximum pressure, e.g. by using a pressure relief valve
-
- 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
- F15B2211/00—Circuits for servomotor systems
- F15B2211/70—Output members, e.g. hydraulic motors or cylinders or control therefor
- F15B2211/705—Output members, e.g. hydraulic motors or cylinders or control therefor characterised by the type of output members or actuators
- F15B2211/7051—Linear output members
- F15B2211/7053—Double-acting output members
-
- 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
- F15B2211/00—Circuits for servomotor systems
- F15B2211/70—Output members, e.g. hydraulic motors or cylinders or control therefor
- F15B2211/75—Control of speed of the output member
-
- 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
- Y10T137/87169—Supply and exhaust
-
- 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
- Y10T137/87169—Supply and exhaust
- Y10T137/87233—Biased exhaust valve
- Y10T137/87241—Biased closed
Definitions
- a Pilot Operated metering-Out valve 51 Int. Cl ..Fl6k 11/00 has its P 9 controlled by t i $9001 to P 581 Field oi Search ..137/596, 625.68, first Sfles of gradually mcreasmg Small opemrfgs 137/6l2.l, 636, 596.2; 91/444 and during final movement of the spool to cause instantaneous opening of a large pilot operated meter- [56] References Cited ing-out valve which opens in a direction opposite to the movement of the main spool.
- the system includes UNITED STATES PATENTS a pilot operated pressure relief valve which provides unloading of the supply pressure when all directional ;,606,426 ll/l926 Justen ..l37/596.2 valves are in neutral, which provides also hydraulic g?igg 5 i detent release for the main spool during slow metering e Sem and when pressure builds up at the end of a motor t Primary ExaminerHenry T. Klinksiek z gf zzg igr fig g gg g f Overload rehef at 3 Assistant Examiner-Robert J. Miller Attorney-Gerhardt, Greenlee & Farris 7 Claims, 4 Drawing Figures a? l 52 I 4 0 22 O as I E m Q W747 @759 .l. O "1 z I PATENTEDHAYPE W5 $734,129
- a hydraulic directional valve system comprising a body having a pair of spoolreceiving bores, each with a lateral port for inlet and for outlet, with an axial port for flow to and from a motor and with a third lateral port connected by a oneway passage with the axial port, a pair of main spools slideable in the bores to control flow between the lateral ports, operating means to shift the spools simultaneously in opposite directions, a seat in each axial port, a poppet coaxial with each spool and biased toward the seat by a spring and by pressure in the axialport, an oppositely facing smaller seat between each spool and its poppet, and a pilot valve normally closing the smaller seat and arranged to be progressively opened by motion of the main spool for metered flow out of the axial port, and means on the pilot valve for rapidly opening the poppet after a further increment of motion of the main spools.
- the present invention aims to provide all of these functions in a single structure which includes a pilot operated hydraulically balanced pressure relief valve comprising a body having an inlet and an outlet, a poppet valve normally closing flow therebetween and having nearly equal opening and closing areas exposed to inlet pressure, a restricted orifice between the inlet and the closing area, manual means for venting the closing area to the outlet to open the poppet at will indepen dently of the inlet pressure, a pilot relief valve exposed to the closing area and having two stages of opening in the first of which at a predetermined pressure the manual means, if not venting the closing area, is caused to move to a venting position and in the second stage, the poppet acts to limit the inlet pressure to a predetermined higher value.
- a pilot operated hydraulically balanced pressure relief valve comprising a body having an inlet and an outlet, a poppet valve normally closing flow therebetween and having nearly equal opening and closing areas exposed to inlet pressure, a restricted orifice between the inlet and the closing area, manual means for venting the
- FIG. 1 is a view, partly in section taken along line 1-1 of FIG. 3, of a pump and valve assembly incorporating a preferred form of the present invention.
- FIG. 2 is a sectional view taken on line 2-2 of FIG. 1.
- FIG. 3 is a top view of the pump and valve assembly illustrated in FIG. 1.
- FIG. 4 is a fragmentary view on a larger scale illustrating a portion of the structure in FIG. 1.
- the pump and valve assembly illustrated in the draw ings comprises a main base plate 10 which functions both as a valve body, as a support for a pump 12 (FIG. 3) and as a closing cover for a suitable opening on a gear casing of a tractor or other power device.
- the pump 12 has a gear 14 which, when the base 10 is se cured in place, will mesh with one of the gears inside the gear housing.
- the pump also carries an inlet filter 16 (FIG. 1) extending downwardly into the gear casing which carries a supply of hydraulic fluid.
- valve body 18 mounted on the base 10 is a directional valve body 18 in which are provided two four-way directional valves 24 and 25, one being controlled by the operating lever or walking beam 20 and the other by a similar lever 22, each of which is pivoted as at 23 to a lug 21 (FIG. 2) on the body 18.
- Each four-way directional valve, which will hereafter be referred to as valves 24 and 25, consists of a structure such as appears in FIG. 2, where the valve 25 is illustrated.
- the following description of valve 25 will be equally applicable to the structure of valve 24.
- the body 18 is provided with two bores 26 and 28 for valve 25 which receive slidable spools 30 and 32 respectively.
- the spools 30 and 32 are identical in structure except spool 30 has detent grooves 66 (latter described herein) and spool 32 has a neutral fluid passing groove (also latter described herein). Spool 32 is illustrated with an alternate feature. This piston 55 and spring 57 are provided to allow the lowering of an actuated cylinder only when the pump 12 is operating. This feature will be described at the end of the specification. The operating lever 22 will move both spools in opposite directions away from the neutral position illustrated. Lateral inlet or supply ports 31 communicate with each valve bore as shown in FIG. 1, and are connected by a passage 33 in the base plate 10 with the delivery port of the pump 12. Lateral outlet ports 34 communicate with the sump via the passage 36 in FIG. 1.
- a terminal block 38 Secured to the bottom of the valve body 18 (FIGS. 1 and 2) is a terminal block 38 which has a pair of motor ports for each of the direc tional valves.
- the ports are shown as ports 40 and 42, in FIG. 2, for valve 25 and one port 42a in FIG. 1 for valve 24. These ports are coaxial with the main valve spools and connect with the bores 26 and 28 through valve seats 44 and 46 respectively.
- Lateral ports 48 and 50 communicate via passages 52 and 54, containing one-way check valves 56 and 59, with the motor ports 40 and 42. Either the lateral port 48 or the lateral port 50 is connected to the supply ports 31 by the grooves 63 or 65 when the operating lever is moved to direct flow through one of the motor ports 40 and 42.
- the grooves 63 and 65 may be provided with V-notches 67 to improve the metering at low rates of flow.
- pilot operated meter-out valves 58 and 60 which are controlled by pilot valves 62 and 64 which move with the respective main spools 30 and 32 to the right of center only.
- One of the spools such as 30 is provided with grooving 66 for cooperation with a spring pressed detent 68 to retain the spool in any of its three positions.
- the detent may be released by admission of pressure fluid through a conduit 70.
- the base includes a pilot operated valve 72 for regulating the delivery of pressure fluid from the pump 12 to the poppet valve body are block 18.
- the valve 72 slides in a bore 74 and seats upon a seat 76 to close off communication between delivery passage 33 and a chamber 78 which is open to the reservoir through exhaust passage 79.
- the poppet valve 72 has an orifice 80 through which inlet pressure is admitted to the inner cylindrical chamber 73 of the valve 72 to act on the upwardly facing or closing area of the poppet valve 72 and with the assistance of a spring 82, normally urges the poppet toward its seat 76. In the position of the parts illustrated in FIG.
- the closing area is vented through ports 75 in the cylindrical wall of valve 72 passages 84, 86, 88 and 90 and the grooves 87, 89 of the spools.
- Orifice 80 creates sufficient pressure drop to such flow that the poppet valve is held open by the full inlet pressure acting on its lower or opening face thereby allowing fluid to pass by the seat 76 and into the chamber 78.
- the flow of fluid through the passages 84, 86, 88, 90 is cut off.
- the poppet 72 is seated by the spring 82.
- a pressure responsive pilot valve 92 is slidable in a fixed ferrule 94 mounted in the bore 74 and held in place by a cap 96.
- a spring 98 allows the pilot relief valve 92 to move upwardly when a predetermined pressure is reached in the bore 74 and will first allow fluid to escape through the valve orifice 93 in the plate 95 and the radial passages 99 in the ferrule 94 into a chamber 100 which connects by passages such as illustrated at 102 in FIGS. 1 and 3 with the passage 70 and the detent 68 a valve 25.
- the pilot valve 92 will rise sufficiently to allow fluid to escape through the exhaust passage 104 and thus poppct 72 will act as a pressure limiting relief valve under these conditions.
- the meter-out valve which is associated with the spool 30 of valve 25, is illustrated there in larger scale and exemplifies the meter-out valves associated with each of the other three spools.
- the piston 55 and spring 57 is shown in FIG. 2 is an alternate form used in all the spools.
- the poppet 58 has a fairly large orifice 106 extending through it to allow fluid to act on its closing surface to hold poppet 58 closed.
- the poppet 58 slides in a bore 108 formed in the body 18. Passages 110 around the cylindrical portion 18a bypasses the opening formed by the bore 108 from the seat 44 to the outlet port 34.
- a smaller seat 112 is formed at the end of inner bore 108 and faces oppositely to the seat 44, being normally closed by the conical portion 112 the pilot valve 62.
- the latter has wings 114 which guide it within the interior bore 116 of the poppet 58 and provide an abutment for the spring 118 which urges both the main poppet 58 and the pilot valve 62 against their respective seats.
- the pilot valve 62 has a restricting pin 120 which is spaced from the orifice 106 sufficiently as to not begin restricting it until the pilot valve 62 has moved to open the seat 112 to its maximum opening.
- the restricting pin approaches the orifice 106 and when the flow therethrough is sufficiently restricted compared with the available flow area at the seat 112, the poppet 58 will rapidly move to the left into the cylindrical portion 18a, further restricting the orifice 106 and providing free flow from the motor port 40 to the outlet port 34 through passages 110. Prior to this, all such flow took place through orifice 106 and the orifice formed by seat 112.
- the area of the latter is governed by the taper on the pilot valve 62 and the degree of its displacement as main spool 30 is moved to the right.
- valve system here disclosed allows very gradual metering out of fluid from the cylinder port along a substantial range of travel of the main spool as previously described. During such travel, pressure is maintained in the opposite cylinder port and in the inlet port because of the wider opening between ports 31 and 48 or 50. This pressure reacts upon the pilot relief valve 92 which opens to admit pressure fluid through passages 102 and to the detent 68 and thus assures that precise control of the valve spools is not inhibited by the detent.
- FIG. 2 This alternative feature is illustrated in FIG. 2, in connection with lower spool 32.
- the spool has a bore 51 at its right-hand end which communicates by a passage 53 with the pressure supply port 31.
- Slidable in the bore 51 is a piston 55 which is urged to the right by a spring 57, which spring is weaker than the spring 122 for the pilot valve 64.
- the pilot valve 64 cannot be opened by piston 55 and spring 57 alone. It requires, in addition, the development of a substantial pressure level in the supply port 31 to hold piston 55 in the position illustrated and thus overcome the force of spring 122 and open pilot valve 64. In this way, the sudden dropping of a heavy load is prevented with less pressure is supplied from port 31.
- the load must be positively lowered by a significant positive pressure applied in the lowering direction.
- a hydraulic directional valve system comprising a body having a pair of spool-receiving bores, each with lateral ports for inlet and for outlet, with an axial port for flow to and from a motor and with a third lateral port connected by a one-way passage with the axial port; pair of main spools slidable in the bores to control flow between the lateral ports, operating means to shift the spools simultaneously in opposite directions, a seat in each axial port, a poppet coaxial with each spool and biased toward the seat by a spring and by pressure in the axial port, and means controlled by the main spool for moving the poppet in a direction opposite to motion of the main spool.
- a hydraulic directional valve system comprising a body having a pair of spool-receiving bores, each with a lateral port for inlet and for outlet, with an axial port for flow to and from a motor and with a third lateral port connected by a one-way passage with the axial port, a pair of main spools slidable in the bores to control flow between the lateral ports, operating means to shift the spools simultaneously in opposite directions, a seat in each axial port, a poppet coaxial with each spool and biased toward the seat by a spring and by pressure in the axial port, an oppositely facing smaller seat between each spool and its poppet, and a pilot valve normally closing the smaller seat and arranged to be progressively opened by motion of the main spool for metered flow out of the axial port and means on the pilot valve for rapidly opening the poppet after a further increment of motion of the main spool.
Landscapes
- Engineering & Computer Science (AREA)
- General Engineering & Computer Science (AREA)
- Mechanical Engineering (AREA)
- Physics & Mathematics (AREA)
- Fluid Mechanics (AREA)
- Fluid-Pressure Circuits (AREA)
- Mechanically-Actuated Valves (AREA)
- Fluid-Driven Valves (AREA)
- Servomotors (AREA)
- Valve Device For Special Equipments (AREA)
- Storage Of Web-Like Or Filamentary Materials (AREA)
- Multiple-Way Valves (AREA)
Applications Claiming Priority (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
US14535571A | 1971-05-20 | 1971-05-20 |
Publications (1)
Publication Number | Publication Date |
---|---|
US3734129A true US3734129A (en) | 1973-05-22 |
Family
ID=22512722
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
US00145355A Expired - Lifetime US3734129A (en) | 1971-05-20 | 1971-05-20 | Hydraulic control valve |
Country Status (8)
Country | Link |
---|---|
US (1) | US3734129A (it) |
CA (1) | CA967074A (it) |
DE (1) | DE2224573C3 (it) |
ES (1) | ES402907A1 (it) |
FR (1) | FR2138778B1 (it) |
GB (3) | GB1393684A (it) |
IT (1) | IT955663B (it) |
ZA (1) | ZA722665B (it) |
Cited By (1)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US3815631A (en) * | 1973-05-01 | 1974-06-11 | Int Harvester Co | Hydraulic control valve |
-
1971
- 1971-05-20 US US00145355A patent/US3734129A/en not_active Expired - Lifetime
-
1972
- 1972-04-19 ZA ZA722665A patent/ZA722665B/xx unknown
- 1972-04-24 CA CA140,386A patent/CA967074A/en not_active Expired
- 1972-05-18 ES ES402907A patent/ES402907A1/es not_active Expired
- 1972-05-18 GB GB5255574A patent/GB1393684A/en not_active Expired
- 1972-05-18 GB GB5255474A patent/GB1393683A/en not_active Expired
- 1972-05-18 GB GB2341572A patent/GB1393682A/en not_active Expired
- 1972-05-19 FR FR727218008A patent/FR2138778B1/fr not_active Expired
- 1972-05-19 DE DE2224573A patent/DE2224573C3/de not_active Expired
- 1972-05-19 IT IT24596/72A patent/IT955663B/it active
Cited By (1)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US3815631A (en) * | 1973-05-01 | 1974-06-11 | Int Harvester Co | Hydraulic control valve |
Also Published As
Publication number | Publication date |
---|---|
ZA722665B (en) | 1973-11-28 |
DE2224573B2 (de) | 1978-05-18 |
DE2224573C3 (de) | 1979-01-11 |
GB1393683A (en) | 1975-05-07 |
IT955663B (it) | 1973-09-29 |
FR2138778A1 (it) | 1973-01-05 |
CA967074A (en) | 1975-05-06 |
ES402907A1 (es) | 1975-04-16 |
FR2138778B1 (it) | 1973-07-13 |
GB1393684A (en) | 1975-05-07 |
GB1393682A (en) | 1975-05-07 |
DE2224573A1 (de) | 1972-11-30 |
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