EP0113708B1 - Soupape de commande du debit d'entree a double commande - Google Patents

Soupape de commande du debit d'entree a double commande Download PDF

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Publication number
EP0113708B1
EP0113708B1 EP19820901677 EP82901677A EP0113708B1 EP 0113708 B1 EP0113708 B1 EP 0113708B1 EP 19820901677 EP19820901677 EP 19820901677 EP 82901677 A EP82901677 A EP 82901677A EP 0113708 B1 EP0113708 B1 EP 0113708B1
Authority
EP
European Patent Office
Prior art keywords
control
pressure
chamber
flow
orifice
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
Application number
EP19820901677
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German (de)
English (en)
Other versions
EP0113708A1 (fr
EP0113708A4 (fr
Inventor
Tadeusz Budzich
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.)
Caterpillar Inc
Original Assignee
Caterpillar Inc
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Filing date
Publication date
Application filed by Caterpillar Inc filed Critical Caterpillar Inc
Publication of EP0113708A1 publication Critical patent/EP0113708A1/fr
Publication of EP0113708A4 publication Critical patent/EP0113708A4/fr
Application granted granted Critical
Publication of EP0113708B1 publication Critical patent/EP0113708B1/fr
Expired 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
    • F15B13/0416—Fluid distribution or supply devices characterised by their adaptation to the control of servomotors for use with a single servomotor with means or adapted for load sensing
    • F15B13/0417—Load sensing elements; Internal fluid connections therefor; Anti-saturation or pressure-compensation valves

Definitions

  • This invention relates generally to flow control valves regulating, irrespective of variations in system pressure, the quantity of fluid flow to a load.
  • this invention relates to flow control valves of a bypass type.
  • this invention relates to flow control valves, in which the bypass member is controlled by a pilot valve.
  • this invention relates to pilot operated flow control valves of a bypass type, which permit variation in the controlled pressure differential between valve inlet pressure and the load pressure, in response to an external control signal.
  • the flow control valves of a throttling or bypass type regulate the flow of fluid to a load by automatically maintaining a constant pressure differential across an orifice leading to the load.
  • the quantity of the flow is varied by the area of orifice, each area corresponding to a specific flow to the load, irrespective of the variations in the system pressure.
  • the controlled constant pressure differential is usually selected quite high, providing a comparatively large throttling loss and therefore affecting the system efficiency.
  • the forces necessary to vary the area of the orifice vary with the size of the valve and are usually quite high.
  • US-A-4153075 discloses a load responsive control valve comprising a bypass valve assembly, supply and control chambers, a bypass member, a pilot valve, control signal modulating means, a variably orifice, and a fixed displacement pump.
  • a load responsive control valve comprising a bypass valve assembly, supply and control chambers, a bypass member, a pilot valve, control signal modulating means, a variably orifice, and a fixed displacement pump.
  • the pressure differential between pump outlet pressure and load pressure is maintained constant at a predetermined level.
  • Another object of this invention is to provide controls for a flow control valve of a bypass type, through which control of flow to system load can be either accomplished by variation in area of the orifice, between the valve control and a fluid motor, while the pressure differential across this orifice is maintained constant at "a specific level, or by control of pressure differential, acting across this ofifice, while the area of the orifice remains constant.
  • a valve assembly comprising a housing having an inlet chamber connected to a pump and to a device supplied with pressure fluid, a bypass chamber connected to fluid exhaust means, control orifice means interposed between the inlet chamber and the device supplied with pressure fluid, first and second control chambers in the housing, first valve means having fluid throttling means between the inlet chamber and the bypass chamber provided with means responsive to pressure in the first control chamber, and pilot valve means operable to control pressure in the first control chamber having means responsive to pressure in the second control chamber and to pressure in the inlet chamber, characterised in that, the first valve means is operable to throttle fluid flow from the inlet chamber to the bypass chamber to maintain a constant pressure differential at a preselected constant level between the inlet chamber and the second control chamber and across the pilot valve means and to maintain a constant pressure differential across the control orifice means, pressure signal transmitting means operable to transmit a control pressure signal from downstram of the control orifice means to the second control chamber and modifying means of the control pressure signal operable through the first
  • the hydraulic system shown therein comprises a fluid pump 10, which may be provided with an output flow control 11, connected to a reservoir 12.
  • the fluid pump 10 is preferably of a fixed displacment type.
  • the fluid pump 10 supplies pressure fluid into a fluid power circuit, composed of a differential bypass control, generally designated as 13, regulating the level of the pressure differential developed across schematically shown variable orifice 14, interposed between the pump 10 and a fluid motor 15, operating load W.
  • a differential bypass control 13 bypasses a portion of flow delivered from the pump 10 to the reservoir 12, to regulate the pressure differential across variable orifice 14.
  • the output flow control 11 of the pump 10 may be a conventional maximum pressure relief valve, well known in the art.
  • the differential bypass control 13 is composed of bypass section, generally designated as 15a, a pilot section, generally designated as 16, a flow control section, generally designated as 17 and a signal throttling section, generally designated as 18.
  • Discharge line 19 of pump 10 is connected to port 20 of differential bypass control 13 and through a check valve 21, line 22, variable orifice 14 and line 23 is also connected to the fluid motor 15.
  • the fluid motor 15 is also connected by lines 23 and 69 with the differential bypass control, generally designated as 13.
  • the bypass section 15a of the differential bypass control 13 comprises a housing 25 having an inlet chamber 26, a bypass chamber 27, a first control chamber 28 and an exhaust chamber 29, all of those chambers being connected by bore 30, slidably guiding a bypass spool 31.
  • the bypass spool 31, equipped with lands 32 and 33 and stop 34, is provided with throttling slots 35, terminated in cut-off edges 36, between the inlet chamber 26 and the bypass chamber 27.
  • the bypass spool 31 projects into the first control chamber 28, while the other end projects into the exhaust chamber 29 and is biased by a control spring 37.
  • the exhaust chamber 29 is connected by passage 38 with the bypass chamber 27 and therefore with the system reservoir 12.
  • the first control chamber 28 is connected by passage 39 with annular space 40 of the pilot valve section, generally designated as 16. Bore 41 connects annular space 40 with port 42 and a second control chamber 43 and axially guides a pilot valve spool 44.
  • the pilot valve spool 44 equipped with metering land 45 and land 46, which define annular space 47, communicates with port 42 and projects into the second control chamber 43, where it engages a spring 48.
  • Annular space 47 is connected by passage 49 with the exhaust chamber 29 and therefore the system reservoir 12.
  • the second control chamber 43 is connected through passage 50 with the signal throttling section, generally designated as 18 and is also connected through passage 51 with the flow control section, generally designated as 17.
  • Passage 51 connects the second control chamber 43 with a supply chamber 52, connected by bore 53 with a third control chamber 54 and an exhaust chamber 55.
  • Bore 53 slidably guides a control spool 56, equipped with land 57, provided with throttling slots 58 and positioned between the supply chamber 52 and the third control chamber 54, a land 59 separating the supply chamber 52 and the exhaust chamber 55.
  • the third control chamber 54 is connected by orifice 60 and passage 61 with the exhaust chamber 55, which contains a spring 62, biasing the control spool 56 and is connected by passage 63 with the exhaust chamber 29.
  • the second control chamber 43 is connected by passage 50 with chamber 64, which is selectively interconnected by metering orifice created by a stem 65 guided in bore 66 and provided with metering slots 67, with signal chamber 68.
  • Signal chamber 68 is connected by line 69 with the fluid motor 15.
  • the stem 65 is connected to an actuator 70, responsive to external control signal 71.
  • Exhaust chambers 55 and 29, connected to the system reservoir 12 are also connected by passages 63 and 49 and orifice 72 with passage 39.
  • the differential bypass control has bypass section 15a, pilot section 16 and flow control section 17 identical to those as shown in Fig. 1.
  • a signal throttling section of Fig. 2, generally designated as 73, is different from the signal throttling section 18 of Fig. 1.
  • the same components used in Figs. 1 and 2 are designated by the same numerals.
  • the second control chamber 43 is connected by passage 50 to chamber 74 of the signal throttling section, generally designated as 73.
  • the signal throttling section 73 comprises a coil 75 retained in the housing, which guides an armature 76 of a solenoid, generally designated as 77.
  • the armature 76 is provided with conical surface 78, selectively engageable with sealing edge 79 of inlet port 80 and venting passage 81, terminating in bore 80 and venting passage 81, terminating in bore 82, guiding a reaction pin 83.
  • the coil 75 is connected by sealed connector 84 to outside of housing 25, external control signal 85 being applied to the sealed connector 84.
  • the differential bypass control 12 is introduced into a ciccuit between the pump 10 and fluid motor 15 and controls the fluid flow and pressure therebetween.
  • the fluid motor 15 can be substituted by any device to which fluid flow must be controlled.
  • the differential bypass control 13 is composed of the bypass section 15a, the pilot section 16, the flow control section 17 and the signal throttling section 18.
  • the bypass section 15a with its bypass spool 31 throttles with throttling slots 35 fluid flow between the inlet chamber 26, connected by discharge line 19 to the pump 10 and the bypass chamber 27, connected to the system reservoir 12 to automatically maintain a constant pressure differential across variable orifice 14, connected by line 23 with the fluid motor 15. This control action is accomplished in the following way.
  • Fluid from upstream of variable orifice 14 of P 1 pressure is supplied to port 42 where, reacting on the cross-sectional area of the pilot valve spool 44, generates a force tending to move the pilot valve spool 44 upward, to connect P 1 pressure through annular space 40 and passage 39 to the first control chamber 28 and therefore to increase the pressure level in the first control chamber 28.
  • Fluid at load pressure Pw which is the pressure acting downstram of variable orifice 14, is supplied by line 69 to the signal throttling section 18.
  • Increase in pressure level in the first control chamber 28, above the level, equivalent to preload of the control spring 37, reacting on the cross-sectional area of the bypass spool 31, will generate a force tending to move the bypass spool 31 from right to left, in the direction of opening of the flow area through the throttling slots 35 and therefore in the direction of increasing the bypass flow by the throttling action of the bypass spool 31.
  • a decrease in pressure level in the first control chamber 28, below the level equivalent to preload of control spring 37 will result in the control spring 37 moving the bypass spool 31 from left to right, in the direction of decreasing the flow area through the throttling slots 35 and therefore in direction of decreasing the bypass flow by the throttling action of the bypass spool 31.
  • the pilot valve spool 44 will control the bypass action of the bypass spool 31 and the quantity of fluid flowing through variable orifice 14. Assume that the stem 65 is fully displaced to the right, providing a minimum resistance to the fluid flow from line 69 to the second control chamber 43.
  • the pilot valve spool 44 subjected to P, and P 2 pressures and the biasing force of spring 48 will reach a modulating position, in which by throttling action of metering land 45 will regulate the pressure in the first control chamber 28 and therefore the bypass action of the bypass spool 31 to regulate the pump P, pressure which is higher, by a constant pressure differential AP, than P 2 pressure and equal to the quotient of the biasing force of spring 48 and the cross-sectional area of the pilot valve spool 44.
  • the pilot valve spool 44 subjected to low energy pressure signals, will act as an amplifying stage using the energy derived from the pump 10 to control the position and therefore the bypass action of the bypass spool 31.
  • Leakage orifice 72 connecting the first control chamber 28 through passage 49 and the exhaust chamber 29 to the reservoir 12, is used, in a well known manner, to increase the stability of the pilot valve spool 44. If P 2 pressure is approximately equal to Pw pressure which is the case when the stem 65 is in the positon fully displaced to the right from the as shown in Fig. 1, the bypass section 15a, by throttling fluid flow from the inlet chamber 26 to the bypass chamber 27, will automatically maintain a constant pressure differential AP between the pump pressure P 1 and P 2 pressure in the second control chamber 43 and with APy becoming AP, will also maintain a constant pressure differential across variable orifice 14.
  • variable orifice 14 With constant pressure differential, acting across an orifice, the flow through an orifice will be proportional to the area of the orifice and independent of pressure in the fluid motor. Therefore, by varying the area of variable orifice 14, the fluid flow to the fluid motor 15 and velocity of the load W can be controlled, each specific area of variable orifice 14 corresponding to a specific velocity of load W, which will remain constant, irrespective of the variation in the magnitude of the load W.
  • fluid flow into fluid motor 15 can be controlled either by variation in area of variable orifice 14, or by variation in pressure differential APy, each of those control methods desplaying identical control characteristics and controlling flow, which is independent of the magnitude of the load pressure.
  • Action of one control can be superimposed on the action of the other, providing a unique system, in which, for example, a command signal from the operator, through the use of variable orifice 14 can be corrected by signal 71 from a computing device, acting through the signal throttling section 18.
  • the flow control valve is similar in construction and performs in a similar way as that of Fig. 1.
  • the bypass section, the pilot section and the flow control section of Figs. 1 and 2 are identical.
  • the signal throttling sections of Figs. 1 and 2 represent different embodiments of the control, which provides similar control characteristics.
  • the signal throttling section of Fig. 2, generally designated as 73 contains the solenoid, generally designated as 77, which consists of coil 75, secured in the housing 25 and the armature 76, slidably guided in the coil 75.
  • the armature 76 is provided with conical surface 78, which, in cooperation with sealing edge 79, regulates the pressure differential ⁇ Px between inlet port 80 and passage 50.
  • the sealed connector 84 in the housing 25, well known in the art, connects the coil 75 with external terminals, to which the external signal 85 can be applied.
  • a solenoid is an electro-mechanical device, using the principle of electro-magnetics, to produce output forces from electrical input signals.
  • the force developed on the solenoid armature 76 is a function of the input current. As the current is applied to the coil 75, each specific current level will correspond to a specific force level, transmitted to the armature. Therefore, the contact force between the conical surface 78 of the armature 76 and sealing edge 79 to housing 25 will vary and be controlled by the input current.
  • the cross-sectional area of the reaction pin 83 must always be smaller than the area enclosed by sealing edge 79, so that a positive force, due to the pressure differential ⁇ Px, opposes the force developed by the solenoid 77.
  • the reaction pin 83 permits use of larger flow passages, while also permitting a very significant reduction in the size of solenoid 77, also permitting the solenoid 77 to work in the higher range of ⁇ Px.
  • the second control chamber 43 is connected to the flow control section 17.
  • the schematically shown actuator 70 of Fig. 1 may respond to many types of external control signals 71.
  • the stem 65 can be manually operated through a mechanical linkage.
  • the actuator 70 may be of a hydraulic or pneumatic type, responding to a hydraulic or pneumatic external control signal, it may be a solenoid or a torque motor, responding to an electrical input current signal, or it may be a stepper motor, responding to a digital electrical external control signal.
  • Figs. 1 and 2 show a dual input flow control system supplying a fluid motor operating a load W.
  • the check valve 21, preventing reverse flow from the fluid motor may be of some value. It should be noted that location of the check valve 21, in the position as shown, or in line 22 past port 42, will to some degree change the operating conditions of the flow control. With the check valve 21 in position as shown in Figs. 1 and 2, variable orifice 14 open and ⁇ Px larger than ⁇ P, the pilot section 16 will be operated by power derived from load W and P 1 will equal zero, with the pump 10 completely unloaded.
  • the flow control valves of Figs. 1 and 2 may control the fluid flow to other devices than fluid motor, for example fuel flow to fuel nozzle or flow of fluid used in a chemical process or mixing operation.
  • the flow to the device can be controlled, at all P w pressure levels, at constant APy by variation in flow area of orifice 14.
  • the flow can also be controlled by variation in APy, but that can be accomplished at Pw pressure levels higher than AP.
  • a constant pressure differential throttling device in the form for example of a spring loaded check, located downstream of variable orifice 14 and throttling the fluid flow to the device, at a level higher than AP, can be inserted in line 23. In this way Pw can not drop below the minimum value of ⁇ P.

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  • Engineering & Computer Science (AREA)
  • Physics & Mathematics (AREA)
  • Fluid Mechanics (AREA)
  • Mechanical Engineering (AREA)
  • General Engineering & Computer Science (AREA)
  • Flow Control (AREA)
  • Control Of Fluid Pressure (AREA)
  • Fluid-Pressure Circuits (AREA)

Claims (7)

1. Ensemble à soupapes (13) comprenant un carter (25) possédant une chambre d'admission (26) raccordée à une pompe (10) et à un dispositif alimenté en fluide sous pression (15), une chambre de dérivation (27) raccordée à des moyens (12) d'évacuation de fluide, des moyens formant orifice de commande (14) intercalés entre la chambre d'admission (26) et le dispositif alimenté en fluide sous pression (15), une première (28) et une seconde (43) chambres de commande (43) situées dans le carter (25), des premiers moyens formant soupape (31) comportant des moyens (35) d'étranglement du fluide, situés entre la chambre d'admission (26) et la chambre de dérivation (27) et comprenant des moyens (33) sensibles à la pression régnant dans la première chambre de commande (28), et des moyens formant soupape pilote (44) agissant de manière à commander la pression dans la première chambre de commande (28) et comprenant des moyens (46, 45) sensibles à la pression régnant dans la seconde chambre de commande (43) et à la pression régnant dans la chambre d'admission (28), caractérisé en ce que les premiers moyens formant soupape (31) peuvent agir de manière à étrangler l'écoulement du fluide depuis la chambre d'admission (26) en direction de la chambre de dérivation (27) afin de maintenir un différentiel de pression constant (AP) à un niveau constant présélectionné entre la chambre d'admission (26) et la second chambre de commande (43) et dans les moyens formant soupape pilote (44), et de maintenir un différentiel de pression constant (APy) dans les moyens formant orifice de commande (14), des moyens (69, 18) d'émission d'un signal de pression agissant de manière à envoyer un signal de pression de commande depuis le côté aval des moyens formant orifice de commande (14) jusqu'à la seconde chambre de commande (43), et des moyens (65, 76, 58) servant à modifier le signal de pression de commande et pouvant agir par l'intermédiaire des premiers moyens formant soupape (31) de manière à modifier le niveau du différentiel de pression constant (APy) commandé au niveau des moyens formant orifice de commade (14), tandis que le différentiel de pression (AP) entre la chambre d'admission (26) et la seconde chambre de commande (43) reste constant au niveau prédéterminé constant.
2. Ensemble à soupapes selon la revendication 1, dans lequel les moyens formant orifice de commande (14) possèdent des moyens formant orifice à surface variable (V).
3. Ensemble à soupapes selon la revendication 1 ou 2, dans lequel les moyens (65, 76, 56) servant à modifier le signal de pression de commande incluent des moyens formant orifice d'écoulement (67, 68).
4. Ensemble à soupapes selon la revendication 3, dans lequel les moyens formant orifice d'écoulement (67, 68) possèdent des moyens formant orifice à surface variable (67, 68).
5. Ensemble à soupapes selon l'une quelconque des revendications précédentes, dans lequel les moyens (65, 76, 56) servant à modifier le signal de pression de commande incluent des moyens (56, 62) de commande de l'écoulement sensibles à la pression.
6. Ensemble à soupapes selon au moins les revendications 3 et 5, dans lequel les moyens formant orifice d'écoulement (67, 68) sont disposés en amont des moyens (56, 62) de commande et l'écoulement sensibles à la pression.
7. Ensemble à soupapes selon l'une quelconque des revendications précédentes, dans lequel les moyens (65, 76, 56) servant à modifier le signal de pression de commande comportent des moyens (70, 65, 73) sensibles à un signal de commande extérieur (71, 85).
EP19820901677 1982-04-19 1982-04-19 Soupape de commande du debit d'entree a double commande Expired EP0113708B1 (fr)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
PCT/US1982/000481 WO1983003644A1 (fr) 1982-04-19 1982-04-19 Soupape de commande du debit d'entree a double commande

Publications (3)

Publication Number Publication Date
EP0113708A1 EP0113708A1 (fr) 1984-07-25
EP0113708A4 EP0113708A4 (fr) 1986-02-10
EP0113708B1 true EP0113708B1 (fr) 1988-11-02

Family

ID=22167939

Family Applications (1)

Application Number Title Priority Date Filing Date
EP19820901677 Expired EP0113708B1 (fr) 1982-04-19 1982-04-19 Soupape de commande du debit d'entree a double commande

Country Status (4)

Country Link
EP (1) EP0113708B1 (fr)
JP (1) JPS59500574A (fr)
DE (1) DE3279180D1 (fr)
WO (1) WO1983003644A1 (fr)

Family Cites Families (10)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
NL169628C (nl) * 1971-06-29 1982-08-02 Ind En Handelmaatschappij Kopp Regelinrichting voor het lastonafhankelijk besturen van hydraulische aandrijfapparaten.
JPS4828884A (fr) * 1971-08-19 1973-04-17
US4153075A (en) * 1975-11-26 1979-05-08 Tadeusz Budzich Load responsive control valve
US4282898A (en) * 1979-11-29 1981-08-11 Caterpillar Tractor Co. Flow metering valve with operator selectable boosted flow
US4285195A (en) * 1980-01-02 1981-08-25 Tadeusz Budzich Load responsive control system
US4330991A (en) * 1980-01-02 1982-05-25 Tadeusz Budzich Load responsive system controls
US4327627A (en) * 1980-01-07 1982-05-04 Tadeusz Budzich Load responsive fluid control valve
US4327763A (en) * 1980-01-11 1982-05-04 Tadeusz Budzich Dual control input flow control valve
US4325289A (en) * 1980-01-11 1982-04-20 Tadeusz Budzich Load responsive fluid control valve
US4333389A (en) * 1980-01-18 1982-06-08 Tadeusz Budzich Load responsive fluid control valve

Also Published As

Publication number Publication date
EP0113708A1 (fr) 1984-07-25
JPS59500574A (ja) 1984-04-05
EP0113708A4 (fr) 1986-02-10
DE3279180D1 (en) 1988-12-08
WO1983003644A1 (fr) 1983-10-27

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