EP0231876A2 - Hydraulikdruck-Steuerung - Google Patents

Hydraulikdruck-Steuerung Download PDF

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Publication number
EP0231876A2
EP0231876A2 EP87101185A EP87101185A EP0231876A2 EP 0231876 A2 EP0231876 A2 EP 0231876A2 EP 87101185 A EP87101185 A EP 87101185A EP 87101185 A EP87101185 A EP 87101185A EP 0231876 A2 EP0231876 A2 EP 0231876A2
Authority
EP
European Patent Office
Prior art keywords
pilot
valve
flow control
pressure
port
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.)
Granted
Application number
EP87101185A
Other languages
English (en)
French (fr)
Other versions
EP0231876A3 (en
EP0231876B1 (de
Inventor
Kazuo Uehara
Tadao Karakama
Sadao Nunotani
Naoki Ishizaki
Masayuki Tanaami
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.)
Komatsu Ltd
Original Assignee
Komatsu Ltd
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Priority claimed from JP61135011A external-priority patent/JP2561819B2/ja
Priority claimed from JP61230029A external-priority patent/JPS62270804A/ja
Application filed by Komatsu Ltd filed Critical Komatsu Ltd
Publication of EP0231876A2 publication Critical patent/EP0231876A2/de
Publication of EP0231876A3 publication Critical patent/EP0231876A3/en
Application granted granted Critical
Publication of EP0231876B1 publication Critical patent/EP0231876B1/de
Anticipated expiration legal-status Critical
Expired - Lifetime legal-status Critical Current

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Classifications

    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F15—FLUID-PRESSURE ACTUATORS; HYDRAULICS OR PNEUMATICS IN GENERAL
    • F15B—SYSTEMS ACTING BY MEANS OF FLUIDS IN GENERAL; FLUID-PRESSURE ACTUATORS, e.g. SERVOMOTORS; DETAILS OF FLUID-PRESSURE SYSTEMS, NOT OTHERWISE PROVIDED FOR
    • F15B13/00—Details of servomotor systems ; Valves for servomotor systems
    • F15B13/02—Fluid distribution or supply devices characterised by their adaptation to the control of servomotors
    • F15B13/04—Fluid distribution or supply devices characterised by their adaptation to the control of servomotors for use with a single servomotor
    • F15B13/0401—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
    • F15B11/00—Servomotor systems without provision for follow-up action; Circuits therefor
    • F15B11/08—Servomotor systems without provision for follow-up action; Circuits therefor with only one 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
    • F15B13/042—Fluid distribution or supply devices characterised by their adaptation to the control of servomotors for use with a single servomotor operated by fluid pressure
    • F15B13/0422—Fluid distribution or supply devices characterised by their adaptation to the control of servomotors for use with a single servomotor operated by fluid pressure with manually-operated pilot valves, e.g. joysticks
    • 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
    • F15B2211/40—Flow control
    • F15B2211/405—Flow control characterised by the type of flow control means or 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
    • F15B2211/40—Flow control
    • F15B2211/405—Flow control characterised by the type of flow control means or valve
    • F15B2211/40507—Flow control characterised by the type of flow control means or valve with constant throttles or orifices
    • 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
    • F15B2211/40—Flow control
    • F15B2211/405—Flow control characterised by the type of flow control means or valve
    • F15B2211/40515—Flow control characterised by the type of flow control means or valve with variable throttles or orifices
    • 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
    • F15B2211/40—Flow control
    • F15B2211/405—Flow control characterised by the type of flow control means or valve
    • F15B2211/40576—Assemblies of multiple 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
    • F15B2211/40—Flow control
    • F15B2211/415—Flow control characterised by the connections of the flow control means in the circuit
    • F15B2211/41572—Flow control characterised by the connections of the flow control means in the circuit being connected to a pressure source and an output member
    • 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
    • F15B2211/40—Flow control
    • F15B2211/42—Flow control characterised by the type of actuation
    • 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
    • F15B2211/40—Flow control
    • F15B2211/42—Flow control characterised by the type of actuation
    • F15B2211/428—Flow control characterised by the type of actuation actuated by fluid pressure
    • 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
    • F15B2211/60—Circuit components or control therefor
    • F15B2211/635—Circuits providing pilot pressure to pilot pressure-controlled fluid circuit elements
    • F15B2211/6355—Circuits providing pilot pressure to pilot pressure-controlled fluid circuit elements having valve means
    • 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
    • F15B2211/60—Circuit components or control therefor
    • F15B2211/67—Methods for controlling pilot pressure

Definitions

  • the present invention relates to hydraulic or oil pressure control systems which are used in oil circuits for driving actuators built in machines designed for con­struction work and, more specifically, to an oil pressure control system in which a flow control valve is provided in an oil input circuit of an actuator to control the flow control valve under the control of a pilot valve.
  • a prior art oil pressure control system of the type referred to is disclosed in U.S. Patent No. 4,535,809 in which, as shown in Fig. 1, flow control valves 'g' are provided in oil input circuits 'c1' and 'c2' connecting an oil pressure pump 'a' and an actuator 'b' and also in oil output circuits 'e1' and 'e2' connecting the actuator 'b' and a tank 'd' to control the inflow rate of the actuator 'b' according to the opening of the respective pilot valves 'f'.
  • Fig. 2 shows a particular arrangement of the pilot valve 'f' and the flow control valve 'g'. More specific strictlyally, input and output ports 'h' and 'i' of the flow control valve 'g' are opened and closed by a poppet 'j'.
  • the poppet 'j' is provided with a throttling slit 'l' to controllably throttle oil under pressure flowing into the input port 'h' and send it through the slit to a back pressure chamber 'k'.
  • the pilot valve 'f' is inserted in a pilot circuit 'm' connected between the back pressure chamber 'k' and the output port 'i'.
  • pilot oil flows through the pilot circuit 'm' at a flow rate corresponding to the opening of the pilot valve 'f'.
  • This pilot oil causes the development of a pressure difference between the input port 'h' and the back pressure chamber 'k', whereby the poppet 'j' is opened by an amount corresponding to the pressure difference so that a predetermined amount of pressurized oil flows from the input port 'h' to the output port 'i'.
  • the gradual opening of the poppet 'j' causes the opened amount of the throttling slit 'l' to be correspondingly increased to gradually increase the rate of the pilot oil flowing from the input port 'h' to the back pressure chamber 'k' and gradually decrease the pressure difference between the input port 'h' and the back pressure chamber 'k'.
  • the movement of the poppet 'j' is stopped as soon as the pressure difference reaches zero. In this way, the flow rate of oil under pressure flowing from the input port 'h' to the output port 'i' is controlled not by the pressure of the input port 'h' but by the opening of the pilot valve 'f'.
  • FIG. 3 Shown in Fig. 3 is another prior art oil pressure control system in which a flow control valve 'g' has a fixed orifice 'l1' provided between a poppet 'j' and an input port 'h' to develop a pressure difference there­between as well as a variable throttle 'l2' provided between a back pressure chamber 'k' and another output port of the valve 'g' leading to the pilot valve 'f' to decrease the opening of the valve 'g' as the poppet 'j' moves upwards.
  • a flow control valve 'g' has a fixed orifice 'l1' provided between a poppet 'j' and an input port 'h' to develop a pressure difference there­between as well as a variable throttle 'l2' provided between a back pressure chamber 'k' and another output port of the valve 'g' leading to the pilot valve 'f' to decrease the opening of the valve 'g' as the poppet 'j' moves upwards.
  • the poppet 'j' is located at a desired position by decreasing an equivalent throttle opening area corresponding to a sum of the throttle opening area of the variable throttle 'l2' and the throttle opening area of the pilot valve 'f' to increase the pressure P B .
  • FIG. 4 an oil pressure control system as yet another prior art, wherein, in a flow control valve 'g', a metering pin 'r' is inserted into an axially-extended bore made in a poppet 'j' so that the metering pin 'r' and a slit provided in the poppet 'j' form a variable throttle S between an input port 'h' and a back pressure chamber 'k'.
  • a primary object of the present invention is, there­fore, to provide an oil pressure control system in which a flow control valve is controlled according to the throttle opening of a pilot valve, and even abrupt opening of the pilot valve enables avoidance of generation of an over-­shooting phenomenon and therefore prevention of momentary, abrupt operation of an actuator operatively associated with the flow control valve.
  • a fixed or stationary throttle is provided in a pressurized oil passage leading to a back pressure chamber in a flow control valve and the back pressure chamber is used as a dampering chamber.
  • the stationary throttle acts as a resistance to such abrupt outflow or inflow, that is, acts to prevent an abrupt change in the pressure of the back pressure cham­ber, whereby the valve body can be smoothly shifted.
  • reference numeral 10 is a pilot valve comprising a pilot variable throttle or a variable throt­tling mechanism
  • reference numeral 20 is a flow control valve controlled by the pilot valve 10.
  • the flow control valve 20 includes a casing 21 which is provided with an input port 22, an output port 23 and a pilot output port 24 and a back pressure chamber 25, the pilot output port 24 communicating with the back pressure chamber 25 through a fixed or stationary orifice 26.
  • a chamber 27 is pro­vided between the input and output ports 22 and 23, and a valve seat 28 is provided on an opening edge of the input port 22 on the side of the chamber 27.
  • a valve body receiving bore 29 which is extended from the chamber 27 to the back pressure chamber 25 with a poppet 30 being inserted into the bore 29.
  • the poppet 30 is provided therein with a spool hole 31.
  • the poppet 30 is also provided with a slit 32 through which the input port 22 is fluidically coupled to the spool hole 31 and with a through-hole 33 through which the output port 24 is fluidically coupled to the spool hole 31, respectively.
  • a spool 34 Inserted into the spool hole 31 is a spool 34 which is fixedly mounted at its one end onto an end face of the back pressure chamber 25.
  • the spool 34 is also formed to have a smaller-diametered in- termediate part, a passage 36 being defined by the intermediate part and the wall of the spool hole 31.
  • the spool 34 is also provided at the other end with a land part 35 which forms a variable throttle 37 together with the slit 32.
  • the flow control valve 20 is coupled at its input port 22 to an outlet side of a pump 40 through a pipe line 41, and at its output port 23 to an actuator 42 through a pipe line 43.
  • the flow control valve 20 is also coupled at its output port 24 to an inlet side of the pilot valve 10 through a pipe line 44, the valve 10 being coupled at its outlet side to the pipe line 43 of the actuator 42 through a pipe line 45.
  • Hydraulic oil discharged out of the pump 40 enters the flow control valve 20 at the input port 22, and then reaches the output port 24 by way of the slit 32 and the through-hole 33.
  • the hydraulic oil arrived at the output port 24 is partly sent through the pipe line 44 to the pilot valve 10 and partly sent through the station­ary throttle 26 to the back pressure chamber 25.
  • a pressure Pi at the input port 22 of the flow control valve 20 is equal to a pressure Pp at the output port 24, that is, the pressure Pi of the input port 22 is equal to a pressure P B in the back pressure chamber 25, so that the poppet 30 is located stationary at such a position as shown in Fig. 6.
  • hydrau­ lic oil will not be sent to the actuator 42.
  • the hydraulic oil of the back pressure chamber 25 is discharged therefrom through the stationary throttle 26 to the output port 24, in which case the stationary throttle 26 acts as a resis­tance so that the poppet 30 is subjected to a force in a direction of reducing the movement speed of the poppet 30, that is, the poppet 30 is subjected to a so-called dampering action. Under influence of this action, the poppet 30 can be smoothly shifted to a predetermined position without any abrupt shift.
  • Fig. 7 Shown in Fig. 7 is another embodiment of the present invention which comprises a flow control valve 50 having a casing 51.
  • the casing 51 is provided therein with an input port 52, output ports 53 and 54 and with a third output port 54 ⁇ .
  • the port 54 ⁇ has a stationary throttle 56 through which the port 54 ⁇ is fluidically coupled to a back pressure chamber 55.
  • a poppet 57 is provided in its center with a recess 58 which is opened to the input port 52, and in its upper part with a slit 59 which communi­cates the recess 58 with an outer peripheral surface of the poppet 57 to form a variable throttle 60 with the output port 54.
  • such a flow control valve 50 arranged as mentioned above is coupled at its input port 52 to a pump 40 through a pipe line 41, at its output port 53 to an actuator 42 through a pipe line 43, at its output port 54 to the pipe line 43 through a pipe line 44 and a pilot valve 10, and at its output port 54 ⁇ to the pipe line 44 through a pipe line 44 ⁇ , respectively.
  • hydraulic oil from the pump is sent to the pilot valve 10 through the input port 52, recess 58, variable throttle 60 and output port 54 of the flow control valve 50 and through the wiring pipe 44.
  • Part of the oil flowing through the pipe line 44 to the pilot valve 10 is supplied through the pipe line 44 ⁇ to the back pressure chamber 55.
  • Upward shift of the poppet 57 causes the opening area of the variable throttle 60 to be gradually increased so that the pressure of the back pressure chamber P B is also gradually increased until the poppet 57 stops.
  • hydraulic oil in the back pressure chamber 55 flows in and out through the stationary throttle 56, during which the stationary throttle 56 functions as a resistance, that is, the poppet 57 is subjected to a force in a direction of reducing the speed of the poppet. i.e., to a so-called dampering action.
  • This action enables smooth shift to the poppet 57 to a predetermined position without any abrupt shift.
  • a casing 71 of a flow control valve 70 has input and output ports 72, 73 and 74 similar to those in Fig. 4.
  • a poppet 75 is provided with first and second stationary throttles 76 and 77 which are fluidically coupled to each other by a passage 78.
  • the poppet 75 is also provided with a slant ring-shaped groove 79 which leads to the passage 78 to form a variable throttle 80 with the output port 74.
  • the variable throttle 80 communicates with a back pressure chamber 81 through the second stationary throttle 77.
  • the flow control valve 70 is coupled at its input port 72 to a pump 40 through a pipe line 41, at its output port 73 to an actuator 42 through a pipe line 43, and at its output port 74 to the pipe line 43 through a pipe line 44 and a pilot valve 10, respectively. Accordingly, hydraulic oil from the pump 40 is supplied partly to the pilot valve 10 through the first stationary throttle 76, variable throt­tle 80, output port 74 and wiring pipe 44, and also supplied partly to the back pressure chamber 81 through the second stationary throttle 77. So long as the throttle opening of the pilot valve 10 is zero, a pressure Pi in the input port 72 is equal to a pressure P B in the back pressure chamber 81, thus resulting in the poppet 75 located at such a position as shown in Fig. 8.
  • Figs. 9 and 10 show an oil pressure control circuit which comprises oil pressure control systems of the present invention to drive an actuator built in a machine designed for construction work.
  • refer­ence numberal 101 is a reciprocating actuator, 102 and 103 first and second supply/return paths or lines connected to both inlet and outlet of the actuator 101, 104 a hydraulic pump, 105 a tank.
  • the first and second lines 102 and 103 are branched respectively into supply and drain lines 102a, 103a and 102b, 103b, the supply lines 102a and 103a being connected to the hydraulic pump 104 through flow control valves 106a and 106b provided on the meter-in side, the drain lines 102b and 103b being connected to the tank 105 through flow control valves 107a and 107b provided on the meter-out side.
  • the flow control valves 107a and 107b on the meter-­out side are valves of a two-way poppet type, and have each a spring 108 for energizing the valve in its closing direction, a pilot port 110 connected through a variable throttle valve 109 to its upstream line to close the upstream line, a pilot port 111 connected to the upstream line to open the upstream line, and a pilot port 112 connected to its downstream line to open the downstream line.
  • the closing pilot ports 110 of the flow control valves 107a and 107b are coupled to the tank side respec­tively through first and second pilot valves 113a and 113b which will be explained later.
  • the closing pilot ports 110 are connected to the tank side through relief valves 114a and 114b which are opened when the supply lines 102a and 103a exceed their predetermined levels in pressure, respectively.
  • the flow control valves 106a and 106b on the meter-in side are valves of a two-way poppet type, and have each, on its closing side, a spring 115 for energiz­ing the valve in its closing direction, a pilot port 116 connected to its upstream line to close the upstream line, a pilot port 117 connected to its downstream line to close the downstream line, while, on its opening side, a pilot port 118 connected to the upstream line through the pilot valve 113a or 113b to open the upstream line, the opening pilot port 118 being connected to the downstream line through a variable throttle 119 and a check valve 120.
  • the variable throttles 109 and 119 are arranged to be opened by closing the flow control valves 106a, 106b, 107a and 107b, respectively.
  • the first and second pilot valves 113a and 113b have each communication and neutral positions A and B to be switched to the communication position A when the associ­ated solenoid is energized.
  • the pilot valves 113a and 113b are arranged to throttle their fluid passing there­through in response to their switching operation.
  • First one 113a of the both pilot valves 113a and 113b is provid­ed between the opening pilot port 118 of the first pilot valve 106 on the first meter-in side and its upstream line and between the closing pilot port 110 of the flow control valve 107b on the second meter-out side and the tank line.
  • the second pilot valve 113b is provided between the opening pilot port 118 of the flow control valve 106b on the second meter-in side and its upstream line and between the closing pilot port 110 of the flow control valve 107a on the first meter-out side and the tank line.
  • the both pilot valves 113a and 113b are arranged to communicate at their communication positions A with the respective pilot lines and at their neutral positions B to close the closing pilot ports 110 on the meter-out side and drain the opening pilot ports 118 on the meter-in side.
  • first flow control valve 106a on the meter-in side is subjected at its opening pilot port 118 to a pressure to open the flow control valve 106a, whereby oil under pressure is supplied from the hydraulic pump 104 to one port of the actuator 101 to drive the actuator in one direction.
  • the flow control valve 107b on the second meter-out side is drained at its closing pilot port 110 through the first pilot valve 113a to the tank line, the return oil flow of the actuator 101 is drained through the flow control valve 107b.
  • the associated variable throttle 119 is opened in response to such valve shift to reduce the pilot pressure at the associated opening pilot port 118, thus correcting such excessive opening of the valve 106a.
  • the rate of oil flowing through the flow control valve 106a is independent of the pressure of oil dis­charged from the hydraulic pump 104 and determined by the pressure at the opening pilot port 118 and therefore by the opening of the pilot valve 113a.
  • reference numeral 121 is a sleeve fitted into a casing 122, into which sleeve 121 a poppet 123 is slidably inserted.
  • the sleeve 121 has an inlet port 124 communi­cating with its upstream line, an outlet port 125 communi­cating with its downstream line, and a stationary throttle port 126 communicating with the opening pilot port 118.
  • the poppet 123 is also provided in its middle with a constricted part 127 which is opposed to the inlet port 124 and also opposed at its one axial land portion to the outlet port 125.
  • the land portion of the constricted part 127 is formed as a valve seat 127a which abuts against a valve seat 121a provided on the sleeve 121 from the side of the outlet port 125.
  • the diameter of the other land portion of the constricted part 127 is larger than that of the valve seat 127a so that when the con­stricted part 127 receives oil under pressure, the valve seat 127a abuts against the valve seat 121a and the poppet 123 is energized in a direction of closing the valve seat 127a, which zone corresponds to the upstream-closing pilot port 116 in Fig. 9.
  • a sta­tionary throttle passage 128 ⁇ through which the stationary throttle port 126 always communicates with a back pressure chamber 128 defined on the rear side of the base end of the poppet 123.
  • a slit 129 which is extended radially to throttlingly communicate, on its one side, with the port 126 as the poppet 123 is shifted in its opening direction and to communicate, on the other side, with a hole 130 made in the poppet 123 along its axial line, which zone corre­sponds to the variable throttle 119 in Fig. 9.
  • the hole 130 is abuttingly closed at its open end by the check valve 120 energized by a spring force in its closing direction.
  • the sleeve 121 is formed to have an opening 131 which communicates with the downstream line at its position opposed to the outlet side of the check valve 121.
  • the spring for energizing the check valve 120 corresponds to the spring 115 shown in Fig. 9.
  • the poppet 123 is fluidically coupled at its tip end face to the downstream line through the opening 131, which zone corresponds to the downstream-closing pilot port 117 shown in Fig. 9.
  • the pressure of the opening pilot port 118 is kept at a constant level determined by the opening of the pilot valve 113a and the position of the poppet 123 is determined by the operating amount of the pilot valve 113a, that is, by the opening of the valve 113a, thus preventing the poppet 123 from being overrun.
  • the poppet 123 is energized in a direction pushing the valve seat 127a to abut against the valve seat 121a to be closed.
  • FIGs. 11 and 12 there is shown an oil pressure control circuit which comprises oil pressure control systems according to another embodiment of the present invention to drive an actuator built-in a machine designed for construction work.
  • substantially the same constituent members as those in the foregoing embodiment of Figs. 9 and 10 are denoted by the same reference numerals for brevity of the explana­tion.
  • the opening pilot ports 118 of the flow control valves 106a and 106b are connected respectively through the variable throttle 119 and check valve 120 to the downstream line.
  • flow control valves 106a and 106b are connected through associated variable throttles 119 to associated downstream lines in which check valves 120 are inserted.
  • the first flow control valve 106a on the meter-in side is subjected at its opening pilot port 118 to a pressure to be opened so that oil under pressure is supplied from a hydraulic pump 104 to one port of the actuator 101 to drive the actuator in one direction.
  • a flow control valve 107b on the second meter-out side is drained at its closing pilot port 110 to the tank line through the first pilot valve 113a, so that the return oil from the actuator 101 is drained through the flow control valve 107b on the second meter-out side.
  • the flow control valve 106a on the first meter-in side is opened excessively, then the associated variable throttle 119 is opened in response to this valve shift and a pilot pressure at the associated opening pilot port 118 of the valve 106a is reduced, thus correcting the excessive opening of the valve 106a.
  • the flow rate of oil flowing through the flow control valve 106a is determined not by the pressure of oil discharged from the hydraulic pump 104 but by the pressure at the opening pilot port 118, that is, by the opening of the pilot valve 113a.
  • a pressure in the downstream line on the meter-in side is higher than a pressure in the pump line, the higher pressure is applied to a downstream-closing pilot port 117 of the flow control valve 106a to close the valve 106a.
  • FIG. 12 A particular arrangement of the flow control valve 106a or 106b on the meter-in side is shown in Fig. 12 in which reference numeral 121 is a sleeve fitted into a casing 122 and the sleeve 121 itself receives a spool 123 ⁇ slidably movable therein.
  • the sleeve 121 is formed to have an inlet port 124 communicating with its upstream line, an outlet port 125 communicating with its downstream line, a stationary throttle port 126 ⁇ through which the opening pilot port 118 communicated with a back pressure chamber 126 defined behind a face of a base end of the spool 123 ⁇ , and a slit 133.
  • the spool 123 ⁇ of a stepped shape comprises a larger-­diametered land part 123a, a smaller-diametered land part 123b, and a constricted part 123c provided between the smaller- and larger-diametered land parts 123a and 123b.
  • the larger-diametered land part 123a is provided in its periphery with an annular groove 131 which is opened to an end face 123d of the smaller-diametered land part 123b through a communication hole or passage 132.
  • the smaller-­diametered land part 123b is provided in its periphery with a plurality of notched grooves 134 arranged in its peripheral direction.
  • the sleeve 121 is provided at its one end with a valve seat 135 against which a valve body 136 of the check valve 120 is pressed under the force of a spring 137.
  • the valve body 136 is provided with a rod 138 an end face of which is closely opposed to the end face 123d of the smaller-diametered land part 123b of the spool 123 ⁇ .
  • the slit 133, larger-diametered land part 123a and annular groove 131 form the variable throttle 119, while the inlet port 124 and notched groove 134 form a variable opening for flow control.
  • the spring 137 for energizing the valve body 136 of the check valve 120 corresponds to the above-mentioned spring 115.
  • the end face 123d of the smaller-diametered land part 123b of the spool 123 ⁇ corresponds to the pilot port 117 for closing the down­stream line.
  • An area difference between the larger-and smaller-diametered land parts 123a and 123b of the spool 123 ⁇ causes the inflow oil to shift the spool 123 ⁇ in its closing direction. The part causing this area difference corresponds to the pilot port 116 for closing the upstream line.
  • the pilot valve 113a when the pilot valve 113a is switched to supply oil to the opening pilot port 118, the oil supplied to the pilot port 118 is supplied through the stationary throttle hole 126 ⁇ to the back pressure chamber 126 so that a pilot pressure acts on the right end face of the spool 123 ⁇ , whereby the spool 123 ⁇ is actuated to its opening direction (leftwardly in Fig. 12).
  • the slit 133 communicates with the annular groove 131 of the larger-diametered land part 123a and thus oil under pressure in the back pressure chamber 126 flows therefrom through the slit 133 and annular groove 131 to the communication hole 132.
  • the spool 123 ⁇ is stopped at a position at which the pressure of the opening pilot port 118 reaches a level determined by the configuration (area ratio between pressure receiv­ing faces) of the spool. That is, the opening of the spool 123 ⁇ is controlled by the opening of the pilot valve 113a so that oil under pressure discharged from the pump 104 is supplied to the check valve 120 through the inlet port 124 and notched groove 134 to open the check valve 120 and then sent to the downstream line.

Landscapes

  • Engineering & Computer Science (AREA)
  • Physics & Mathematics (AREA)
  • Fluid Mechanics (AREA)
  • Mechanical Engineering (AREA)
  • General Engineering & Computer Science (AREA)
  • Fluid-Pressure Circuits (AREA)
EP87101185A 1986-01-30 1987-01-28 Hydraulikdruck-Steuerung Expired - Lifetime EP0231876B1 (de)

Applications Claiming Priority (6)

Application Number Priority Date Filing Date Title
JP1693486 1986-01-30
JP16934/86 1986-01-30
JP135011/86 1986-06-12
JP61135011A JP2561819B2 (ja) 1986-06-12 1986-06-12 流量制御弁
JP61230029A JPS62270804A (ja) 1986-01-30 1986-09-30 油圧制御装置
JP230029/86 1986-09-30

Publications (3)

Publication Number Publication Date
EP0231876A2 true EP0231876A2 (de) 1987-08-12
EP0231876A3 EP0231876A3 (en) 1988-08-10
EP0231876B1 EP0231876B1 (de) 1991-05-22

Family

ID=27281624

Family Applications (1)

Application Number Title Priority Date Filing Date
EP87101185A Expired - Lifetime EP0231876B1 (de) 1986-01-30 1987-01-28 Hydraulikdruck-Steuerung

Country Status (2)

Country Link
EP (1) EP0231876B1 (de)
DE (1) DE3770178D1 (de)

Cited By (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0289337A2 (de) * 1987-04-30 1988-11-02 AlliedSignal Inc. Magnetventil
EP0354972A1 (de) * 1988-02-24 1990-02-21 Hitachi Construction Machinery Co., Ltd. Ventilanordnung
EP0468944A1 (de) * 1990-07-24 1992-01-29 Bo Andersson Einrichtung zur Steuerung hydraulischer Motoren
EP0716235A3 (de) * 1994-11-10 1996-09-25 Kawasaki Heavy Ind Ltd Hydraulisch betätigbares Ventil
WO2005111430A1 (de) * 2004-05-13 2005-11-24 Danfoss A/S Hydraulik-ventilanordnung, insbesondere wasserhydraulik-ventilanordnung
CN109821163A (zh) * 2019-01-30 2019-05-31 龙岩学院 一种感载缓冲缓降装置

Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3269416A (en) * 1964-05-25 1966-08-30 American Brake Shoe Co Control valve mechanism with means for reducing hydraulic shock
GB1314389A (en) * 1970-07-14 1973-04-18 Koehring Co Pilot operated control valve
EP0079870A2 (de) * 1981-09-28 1983-05-25 Bo Andersson Hydraulisches Ventil
EP0095782A1 (de) * 1982-06-01 1983-12-07 Deere & Company Steuerventil für hydraulische Präzisionssteuerungen

Patent Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3269416A (en) * 1964-05-25 1966-08-30 American Brake Shoe Co Control valve mechanism with means for reducing hydraulic shock
GB1314389A (en) * 1970-07-14 1973-04-18 Koehring Co Pilot operated control valve
EP0079870A2 (de) * 1981-09-28 1983-05-25 Bo Andersson Hydraulisches Ventil
US4535809A (en) * 1981-09-28 1985-08-20 Bo Andersson Hydraulic valve means
EP0095782A1 (de) * 1982-06-01 1983-12-07 Deere & Company Steuerventil für hydraulische Präzisionssteuerungen

Cited By (10)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0289337A2 (de) * 1987-04-30 1988-11-02 AlliedSignal Inc. Magnetventil
EP0289337A3 (en) * 1987-04-30 1990-09-26 Allied-Signal Inc. Solenoid valve
EP0354972A1 (de) * 1988-02-24 1990-02-21 Hitachi Construction Machinery Co., Ltd. Ventilanordnung
EP0354972A4 (en) * 1988-02-24 1990-09-19 Hitachi Construction Machinery Co., Ltd. Valve device
US5140815A (en) * 1988-02-24 1992-08-25 Hitachi Construction Machinery Co., Ltd. Valve apparatus
EP0468944A1 (de) * 1990-07-24 1992-01-29 Bo Andersson Einrichtung zur Steuerung hydraulischer Motoren
EP0716235A3 (de) * 1994-11-10 1996-09-25 Kawasaki Heavy Ind Ltd Hydraulisch betätigbares Ventil
WO2005111430A1 (de) * 2004-05-13 2005-11-24 Danfoss A/S Hydraulik-ventilanordnung, insbesondere wasserhydraulik-ventilanordnung
CN109821163A (zh) * 2019-01-30 2019-05-31 龙岩学院 一种感载缓冲缓降装置
CN109821163B (zh) * 2019-01-30 2020-07-24 龙岩学院 一种感载缓冲缓降装置

Also Published As

Publication number Publication date
EP0231876A3 (en) 1988-08-10
DE3770178D1 (de) 1991-06-27
EP0231876B1 (de) 1991-05-22

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