CN1274965C - Hydraulic circuit device - Google Patents

Hydraulic circuit device Download PDF

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Publication number
CN1274965C
CN1274965C CNB028023161A CN02802316A CN1274965C CN 1274965 C CN1274965 C CN 1274965C CN B028023161 A CNB028023161 A CN B028023161A CN 02802316 A CN02802316 A CN 02802316A CN 1274965 C CN1274965 C CN 1274965C
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China
Prior art keywords
pressure
valve
mentioned
electromagnetic proportional
supply
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CNB028023161A
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Chinese (zh)
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CN1464945A (en
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宫城淳一
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Daikin Industries Ltd
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Daikin Industries Ltd
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    • 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
    • F15B21/00—Common features of fluid actuator systems; Fluid-pressure actuator systems or details thereof, not covered by any other group of this subclass
    • F15B21/08—Servomotor systems incorporating electrically operated control means
    • F15B21/087—Control strategy, e.g. with block diagram
    • 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
    • F15B9/00—Servomotors with follow-up action, e.g. obtained by feed-back control, i.e. in which the position of the actuated member conforms with that of the controlling member
    • F15B9/02—Servomotors with follow-up action, e.g. obtained by feed-back control, i.e. in which the position of the actuated member conforms with that of the controlling member with servomotors of the reciprocatable or oscillatable type
    • F15B9/03—Servomotors with follow-up action, e.g. obtained by feed-back control, i.e. in which the position of the actuated member conforms with that of the controlling member with servomotors of the reciprocatable or oscillatable type with electrical control means
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F04—POSITIVE - DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS FOR LIQUIDS OR ELASTIC FLUIDS
    • F04B—POSITIVE-DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS
    • F04B49/00—Control, e.g. of pump delivery, or pump pressure of, or safety measures for, machines, pumps, or pumping installations, not otherwise provided for, or of interest apart from, groups F04B1/00 - F04B47/00
    • F04B49/02—Stopping, starting, unloading or idling control
    • F04B49/022—Stopping, starting, unloading or idling control by means of 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
    • 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
    • F15B11/161—Servomotor systems without provision for follow-up action; Circuits therefor with two or more servomotors with sensing of servomotor demand or load
    • F15B11/165—Servomotor systems without provision for follow-up action; Circuits therefor with two or more servomotors with sensing of servomotor demand or load for adjusting the pump output or bypass in response to demand
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F04—POSITIVE - DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS FOR LIQUIDS OR ELASTIC FLUIDS
    • F04B—POSITIVE-DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS
    • F04B2205/00—Fluid parameters
    • F04B2205/05—Pressure after the pump outlet
    • 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
    • F15B2211/40—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
    • F15B2211/40553—Flow control characterised by the type of flow control means or valve with pressure compensating 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
    • F15B2211/41—Flow control characterised by the positions of the valve element
    • F15B2211/413—Flow control characterised by the positions of the valve element the positions being continuously variable, e.g. as realised by proportional 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
    • F15B2211/41581—Flow control characterised by the connections of the flow control means in the circuit being connected to an output member and a return line
    • 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
    • F15B2211/426—Flow control characterised by the type of actuation electrically or electronically
    • 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
    • F15B2211/50563—Pressure control characterised by the type of pressure control means the pressure control means controlling a differential pressure
    • F15B2211/50572—Pressure control characterised by the type of pressure control means the pressure control means controlling a differential pressure using a pressure compensating valve for controlling the pressure difference across a flow 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
    • F15B2211/50—Pressure control
    • F15B2211/515—Pressure control characterised by the connections of the pressure control means in the circuit
    • F15B2211/5157—Pressure control characterised by the connections of the pressure control means in the circuit being connected to a pressure source and a return line
    • 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
    • F15B2211/52—Pressure control characterised by the type of actuation
    • F15B2211/528—Pressure 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
    • F15B2211/605—Load sensing circuits
    • 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
    • F15B2211/63—Electronic controllers
    • F15B2211/6303—Electronic controllers using input signals
    • F15B2211/6306—Electronic controllers using input signals representing a pressure
    • F15B2211/6309—Electronic controllers using input signals representing a pressure the pressure being a pressure source supply 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
    • F15B2211/63—Electronic controllers
    • F15B2211/6303—Electronic controllers using input signals
    • F15B2211/632—Electronic controllers using input signals representing a flow rate
    • F15B2211/6323—Electronic controllers using input signals representing a flow rate the flow rate being a pressure source flow rate
    • 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
    • F15B2211/665—Methods of control using electronic components
    • F15B2211/6655—Power control, e.g. combined pressure and flow rate 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
    • F15B2211/60—Circuit components or control therefor
    • F15B2211/665—Methods of control using electronic components
    • F15B2211/6656—Closed loop control, i.e. control using feedback

Abstract

A hydraulic circuit device (2, 20), comprising an electromagnetic proportional valve (6) having a supply position for supplying hydraulic oil to a main engine side, a discharge position for discharging the hydraulic oil from the main engine side, and a stop position for stopping the supply and discharge of the hydraulic oil installed in a hydraulic oil feed passage (5) to a main engine hydraulic circuit (1) to regulate the supply flow and pressure of the hydraulic oil, a pressure sensor (10) for detecting the pressure of the hydraulic oil in a downstream side supply passage (5b), and a position sensor (11) for detecting the spool position (opening) of the electromagnetic proportional valve (6), wherein, based on signals from the pressure sensor (10) and the position sensor (11), the opening of the electromagnetic proportional valve (6) is controlled to feedback by a digital controller (12) so that the supply flow (Q) or the supply pressure (P) of the hydraulic oil to the main engine side becomes an instruction value (Qi) or (Pi), whereby the controllability of the supply flow and pressure of the hydraulic oil can be increased while suppressing an increase in cost, and particularly the controllable area of the pressure can be extended to a zero point.

Description

Circuit apparatus for hydraulic
Technical field
The present invention relates to a kind of circuit apparatus for hydraulic that is used for the hydraulic actuator of drive mechanism, particularly belong to the movement speed and flow that be used as power, working solution and the pressure controlled technical field that are used for suitably controlling this actuator.
Background technique
Past, as this circuit apparatus for hydraulic, known be useful on control to the electromagnetic proportional valve (the following flow proportion valve that also abbreviates as) of the supply flow of the working oil of actuator and be used to adjust the electromagnetic proportional valve (the following pressure proportioning valve that also abbreviates as) of pressure, by the circuit apparatus for hydraulic of each Proportional valve of driving circuit controls of special use.
Wherein, as Fig. 6 illustrates the one example, in the supply passage 5 of the working oil of the hydraulic actuator of main frame oil hydraulic circuit 1 flow proportion valve 6 is being set, the A mouth in the downstream side of this flow proportion valve 6 connects above-mentioned actuator, for example connects metering pump 3 at the P of upstream side mouth.In addition, be provided with and accept pilot pressure respectively, make these differential pressures be roughly the pressure difference compensation valve 7 that from the supply passage 5a of upstream side working oil is bypassed to the T mouth definitely from the upstream side and the downstream side of above-mentioned flow proportion valve 6.
In addition, from the control channel 15 in the downstream side of the downstream side of flow proportion valve 6 guiding pilot pressure throttle orifice 17 is set at above-mentioned relatively pressure difference compensation valve 7, control channel 15 between this throttle orifice 17 and pressure difference compensation valve 7 makes the working oil unloading adjust the pressure proportioning valve 8 of the pilot pressure in downstream side thereby connect from this.The aperture of above-mentioned flow proportion valve 6 and pressure proportioning valve 8 is respectively by independently current driver 9,9 controls.
The start of the circuit apparatus for hydraulic in the past of Gou Chenging so automatically switches to flow control mode and pressure control mode corresponding to the operating state of actuator.Promptly, for example in occasion from working oil to the oil hydraulic cylinder of main frame that supply with, when this oil hydraulic cylinder moves, keep substantially under certain state by pressure difference compensation valve 7 in the front and back of flow proportion valve 6 differential pressure, aperture by this flow proportion valve 6 is controlled the supply oil mass of adjusting to oil hydraulic cylinder, controls its movement speed (flow control mode).At this moment, the working oil of discharging from pump 3 is given to oil hydraulic cylinder by P mouth, flow proportion valve 6, A confession, and simultaneously, remaining working oil is bypassed to fuel tank 4 from pressure difference compensation valve 7 by the T mouth.
When cylinder reaches stroke terminal, the hydraulic pressure of the supply passage 5b in downstream side sharply rises, when the setting pressure of this hydraulic pressure Overpressure of a safety valve Proportional valve 8, this pressure proportioning valve 8, pressure difference compensation valve 7, and throttle orifice 17 work as so-called controlling type solenoid-operated proportional safety valve, stop the increase of this above hydraulic pressure.The pilot pressure of the downstream side control channel 15 of this moment can change the unloading pressure of pressure difference compensation valve 7 thus by the control break of the unloading pressure of pressure proportioning valve 8, thus the head pressure of control pump 3 and to the supply pressure (pressure control mode) of oil hydraulic cylinder.
; occasion at the circuit apparatus for hydraulic in past as described above; because to the supply flow of the working oil of actuator and pressure has all reacted solenoid valve 6,8 according to former state solenoidal characteristic; so; the flow of working oil or variation in pressure are non-linear from the output current value of current driver 9 relatively; exist to lag behind (with reference to the diagram of dotted line among Fig. 4), in the control of the flow of working oil and pressure, be difficult to obtain enough precision.In addition, owing to do not make the open type control of power demand sensor, so, also there is the problem that the speed of response of the variation of relative instruction value can not be improved De Taigao.
In addition, there be the problem relevant with the control limit of low voltage side in the control for the supply pressure of working oil.Promptly, occasion at the example in above-mentioned past, even current value drops to zero to pressure proportioning valve 8, the unloading pressure of pressure difference compensation valve 7 also only drops to the authorized pressure suitable with the elastic force of spring component, can not be lower than afore mentioned rules pressure to the supply pressure of actuator.In other words, in the structure of example in the past, because for utilizing the pressure control of safety valve, so, there is the lower limit (following also claim minimum pilot pressure) of controllable hydraulic pressure, can not carry out the pressure control of this following low pressure.For this point, for example in the occasion of injection molding machine, there is the operation of the low pressure matched moulds of setting for protective money belongs to mould, in this operation, require control at the pressure lower than minimum pilot pressure of past.That is, in the circuit apparatus for hydraulic in the past, pressure control is also wished to improve strongly.
Summary of the invention
The present invention makes in view of this point, its purpose is to provide a kind of valve constitution, the circuit apparatus for hydraulic 2,20 of this valve constitution is provided with electromagnetic proportional valve 6 at the supply passage 5 of the working solution that feeds to hydraulic actuator, the supply flow of Control work liquid and pressure, in this circuit apparatus for hydraulic 2,20, improve its control accuracy and responsiveness, simultaneously, particularly can eliminate its minimum pilot pressure, expand the zone of control of pressure to zero point substantially for supply pressure, in addition, can suppress cost rises.
The present invention is in order to address the above problem the following measure of taking.
First invention is prerequisite with circuit apparatus for hydraulic 2,20, this circuit apparatus for hydraulic 2,20 is provided with the electromagnetic proportional valve 6 that the supply flow of working solution is adjusted in the supply passage 5 of the working solution that feeds to hydraulic actuator, simultaneously, pressure difference compensation valve 7 is set, and described pressure difference compensation valve 7 is accepted pilot pressure from the upstream side of this electromagnetic proportional valve 6 and downstream side respectively and is made its differential pressure make working solution be bypassed to fuel tank 4 for the supply passage 5a from upstream side definitely.
Above-mentioned electromagnetic proportional valve 6 at least also has the drain position of discharging working solution from this actuator except having to the supply position of actuator supply working solution, have the working hydraulic pressure of the supply passage 5b that detects above-mentioned downstream side and export the pressure transducer 10 of electrical signal, detect the valve rod position of above-mentioned electromagnetic proportional valve 6 and export the position transducer 11 of electrical signal, and controller 12, described controller 12 is accepted from the signal of above-mentioned pressure transducer 10 and position transducer 11 outputs respectively and is made to the supply flow of the working liquid body of above-mentioned actuator and the aperture that supply pressure becomes the above-mentioned electromagnetic proportional valve 6 of control command value ground feedback control.
According to this invention, in the course of action of actuator, keep substantially under certain state by the function of pressure difference compensation valve 7 in the front and back of electromagnetic proportional valve 6 differential pressure,, control supply flow (flow control mode) thus to actuator by the valve rod position of controller 12 these electromagnetic proportional valves 6 of control.At this moment, the valve rod position of the reality of electromagnetic proportional valve 6 is detected by position transducer 11, carries out feedback control according to its testing result, so the precision of the flow control of working solution and responsiveness are all very high.In addition, can absorb solenoidal nonlinear characteristics on apparent by feedback control, so, can make working solution flow control the characteristic linearization and also can eliminate hysteresis.
On the other hand, become the state that arrives stroke terminal and be failure to actuate substantially as actuator, then the hydraulic pressure of the supply passage 5b in downstream side increases along with the increase of load, this state is detected by pressure transducer 10, is carried out the feedback control (pressure control mode) of electromagnetic proportional valve 6 by controller 12 corresponding to this checkout value.Promptly, when electromagnetic proportional valve 6 is in the supply position, adjust supply flow according to the checkout value of pressure transducer 10 and the deviation of pressure instruction value by the control of the aperture (valve rod position) of electromagnetic proportional valve 6, on the other hand, when electromagnetic proportional valve 6 is in drain position, adjust, thereby finally the hydraulic pressure of this supply passage 5b can be maintained pressure instruction value ground control valve rod position from the discharge capacity of the supply passage 5b in downstream side.For this pressure control mode, also similarly improve control accuracy, responsiveness, solenoidal nonlinear characteristics etc. by feedback control with above-mentioned flow control mode.In addition,, discharge working solution, can make supply pressure be reduced to zero to this actuator from actuator by as described above electromagnetic proportional valve 6 being switched to drain position.
And, according to foregoing invention, compare with the formation in past, also need pressure transducer 10 and position transducer 11 in addition, but do not need pressure proportioning valve 8 and corresponding current drives loop, so, can offset the cost that adopts electric transducer to cause and rise.
In second invention,, have flow deviation operational part 12b, pressure divergence operational part 12a, PQ selection portion 12c, current driver 12d as the controller 12 of circuit apparatus for hydraulic 2,20; This flow deviation operational part 12b simultaneously, deducts this effective supply amount, calculated flow rate deviation from the flow instruction value according to the effective supply amount of obtaining from the signal of position transducer 11 to the working solution of actuator; This pressure divergence operational part 12a simultaneously, deducts this effective supply pressure, calculating pressure deviation from the pressure instruction value according to the effective supply pressure of obtaining from the signal of pressure transducer 10 to the working solution of actuator; This PQ selection portion 12c selects the deviation of the less side of numerical value in above-mentioned flow deviation and the pressure divergence, according to the target valve rod position of the deviation calculation electromagnetic proportional valve 6 of this selection; This current driver 12d applies electric current to become the target location that is calculated by above-mentioned PQ selection portion 12c at the solenoid 6b of the valve rod 6a of electromagnetic proportional valve 6.
According to this invention, by the effective supply flow of flow deviation operational part 12b evaluation work liquid and the flow deviation between the flow instruction value, simultaneously, by the effective supply pressure of pressure divergence operational part 12a evaluation work liquid and the pressure divergence between the pressure instruction value.When its actual supply flow and effective supply pressure surpass control command value, surpass a more side as all be in again below the command value, then by PQ selection portion 12c selection more near a side of command value.That is, PQ selection portion 12c judges that the command value of Overpressure of a safety valve and flow is a hazardous condition, judges its hazard level according to each deviation of flow and pressure, selects the bigger side's of hazard level deviation, thereby realizes the action effect of above-mentioned first invention.
In the 3rd invention, has the spring 7b that the pressure difference compensation valve 7 of circuit apparatus for hydraulic 2,20 applies elastic force towards a side of cutting out this valve body 7a, be subjected to pilot pressure at a side joint of closing this valve body 7a from the downstream side of electromagnetic proportional valve 6, on the other hand, a side joint of opening at valve body 7a is subjected to the pilot pressure from the upstream side of electromagnetic proportional valve 6.At control channel 15 configurations in the downstream side that pilot pressure is guided to pressure difference compensation valve 7 from the downstream side of above-mentioned electromagnetic proportional valve 6 the mobile throttle orifice 17 that carries out throttling to working solution, in addition, be connected control safety valve 18 with downstream side control channel 15 between the pressure difference compensation valve 7 at this throttle orifice 17.
According to this invention, even the valve rod 6a of electromagnetic proportional valve 6 supplies with the position because of the electrical failure of controller 12 or the foreign matter of working solution etc. are parked in and can not move, when the hydraulic pressure of downstream side supply passage 5b surpasses the setting pressure of control safety valve 18, control safety valve 18, pressure difference compensation valve 7, throttle orifice 17 work as so-called controlling type safety valve, prevent the increase of the hydraulic pressure of above-mentioned downstream side supply passage 5b.In addition, when the valve body 7a of this pressure difference compensation valve 7 carried out on-off action, flowing of the working solution of the control channel 15 in downstream side accepted by resistance from throttle orifice 17, thereby the action of above-mentioned valve body 7a is applied appropriate buffering, realizes stabilization.
, when downstream side control channel 15 configuration section discharge orifices 17 restraint of labour liquid mobile, the movement speed of the valve body 7a of pressure difference compensation valve 7 is descended like this, so, when increasing working solution to the supply flow of actuator, the possibility that exists responsiveness to descend.That is, when in order to increase working solution to the supply flow of actuator and when increasing the aperture of electromagnetic proportional valve 6, the front and back differential pressure of this electromagnetic proportional valve 6 is reduced for the moment, the valve body 7a of shut off differential pressure recuperation valve 7.In detail, working solution flows towards pressure difference compensation valve 7 in the control channel 15 in downstream side, the valve body 7a that makes this pressure difference compensation valve 7 is towards closing side shifting, but the power of wanting valve body 7a is the elastic force degree of spring 7b, in addition, and by throttle orifice 17 flowing of restraint of labour liquid as described above, like this, cause the closing motion of the valve body 7a of pressure difference compensation valve 7 to postpone, thus, produce operating lag in increase to the supply flow of electromagnetic proportional valve 6.
Consider the delay of transition as described above, the circuit apparatus for hydraulic 20 of above-mentioned the 3rd invention in series disposes first segment discharge orifice 21 and the second strong throttle orifice 22 of Bi Qi throttle degree in downstream side control channel 15, simultaneously, allow that in passage 23 configuration of this second throttle orifice 22 of bypass working solution flows but one-way valve 24 (the 4th invention) that its counter current is stoped to pressure difference compensation valve 7.
Like this, for example, when in order to increase working solution and to increase the aperture of electromagnetic proportional valve 6 to the supply flow of actuator, working solution flows to pressure difference compensation valve 7 in downstream side control channel 15, though this working solution flow through the less first segment discharge orifice 21 of throttle degree, but because strong second throttle orifice, 22 bypass of throttle degree, so, can reduce relatively, promptly the valve body 7a of shut off differential pressure recuperation valve 7 by resistance, like this, can promptly increase the supply flow of working solution to actuator.
On the other hand, when reducing working solution to the supply flow of actuator, reduce the aperture of electromagnetic proportional valve 6, but this moment this electromagnetic proportional valve 6 the hydraulic pressure of upstream side sharply increase, high hydraulic pressure makes this valve body 7a start work in the valve body 7a of pressure difference compensation valve 7.At this moment, side supply passage 5b is mobile downstream from pressure difference compensation valve 7 for working solution in downstream side control channel 15, and this flows and accepts to pass through resistance from throttle orifice 21,22 of above-mentioned first and second both sides.Yet, as described above, because pilot pressure at the high upstream side of the valve body 7a of pressure difference compensation valve 7 effect, so even the mobile of working solution is restricted in downstream side control channel 15, the valve body 7a of pressure difference compensation valve 7 also enough promptly opens start, the result, operating lag can not become problem when supply flow reduced, the flowing of downstream side control channel 15 by the 22 abundant throttlings of second throttle orifice, thus can keep the operating stably of pressure difference compensation valve 7.
Promptly, according to above-mentioned the 4th invention, by the throttle orifice 21,22 that is disposed at downstream side control channel 15 the starting of valve body 7a of pressure difference compensation valve 7 is restricted to the degree of not damaging its responsiveness, guarantee stability, on the other hand, can guarantee responsiveness by not limiting the closing action of this valve body 7a.Therefore, can on higher level, satisfy stability and the responsiveness of working solution simultaneously to the supply flow of actuator.
In the 5th invention, hydraulic actuator is specified to the actuator that is used to drive injection molding machine.
Promptly, occasion at the actuator of general injection molding machine, requirement is corresponding and have a high reproducibility corresponding to the big molding condition of the different and width of the shape of profiled member and material, so, circuit apparatus for hydraulic 2,20 by above-mentioned first invention can improve the movement speed of actuator and the control accuracy that is used as power, this is very effective, for this reason, and the increasing substantially of the quality that can realize being shaped.
In addition,,, supply pressure to the working solution of actuator controls because being dropped to zeroly according to above-mentioned first invention, so, the also fully requirement of correspondence in the low pressure matched moulds operation of injection molding machine.In addition, for example above-mentioned the 4th invention like that increases the supply flow of working solution as responsiveness that can be good, and then the shaping of the drip molding of the thin-walled of injection molding machine is easy, and the circulation that is shaped also can be shortened.From such viewpoint, be applicable to the occasion of injection molding machine, the action effect of invention is very effective.
According to the present invention, circuit apparatus for hydraulic 2,20 are being provided with electromagnetic proportional valve 6 in the supply passage 5 of the working solution of hydraulic actuator, simultaneously, pressure difference compensation valve 7 is being set, from the upstream side of this electromagnetic proportional valve 6 with pilot pressure is accepted in the downstream side respectively and its differential pressure becomes the occasion that makes the working solution bypass definitely from the supply passage 5a of upstream side, append the drain position of discharging working solution from actuator at above-mentioned electromagnetic proportional valve 6, simultaneously, be provided with the downstream side of detecting this electromagnetic proportional valve 6 supply passage 5b working hydraulic pressure pressure transducer 10 and detect the position transducer 11 of the valve rod position of electromagnetic proportional valve 6, valve rod position (aperture) according to these signal of sensor feedback control electromagnetic proportional valves 6, so, can make the supply flow of working solution and pressure controlled precision high.
And, on apparent, eliminate solenoidal nonlinear characteristics by feedback control, can make the control characteristic linearization of the supply flow and the pressure of working solution, in addition, the comparable past is improved the opening and closing speed of electromagnetic proportional valve 6, improves the flow responsiveness.In addition,, then can discharge working solution from actuator as electromagnetic proportional valve 6 is switched to drain position, so, can make pilot pressure drop to zero, reduce out of contior zone.
In addition, because do not need the pressure proportioning valve 8 and the corresponding current driver circuits of needs in the past, so, but the cost that causes that appends of offset sensor increases.
According to second invention, can carry out the feedback control of electromagnetic proportional valve 6 corresponding to the supply condition of the reality of working solution by flow deviation operational part 12b, the pressure divergence operational part 12a of the controller 12 of being located at circuit apparatus for hydraulic 2,20, PQ selection portion 12c etc., obtain the effect of above-mentioned first invention fully.
According to the 3rd invention, owing to from the downstream side control channel 15 of the downstream side guiding pilot pressure of electromagnetic proportional valve 6 mobile throttle orifice 17 and the control safety valve 18 that carries out throttling to working solution is set at the pressure difference compensation valve 7 of relative circuit apparatus for hydraulic 2,20, so, at controller 12 and electromagnetic proportional valve 6 just in case also can obtain sufficient Security when breaking down, simultaneously, the action of the valve body 7a of above-mentioned pressure difference compensation valve 7 is applied the buffering of appropriateness, make its action stabilization.
According to the 4th invention, throttle orifice as above-mentioned the 3rd invention, in series dispose the throttle degree first and second different throttle orifices 21,22 mutually, passage 23 configuration one-way valves 24 at the second strong throttle orifice 22 of bypass throttle degree wherein, this valve body 7a's close the action speed up thereby can make in the action stability of guaranteeing pressure difference compensation valve 7, when the delivery volume that increases to the working solution of actuator, can further improve its flow responsiveness.
According to the 5th invention,, can boost productivity by the shortening of cycle time by circuit apparatus for hydraulic 2,20 is applicable to injection molding machine, simultaneously, can be by the controlled shaping quality that increases substantially that improves start speed and be used as power, in addition, the shaping of the moulding product of film is easy.In addition, the requirement under also can abundant corresponding low pressure matched moulds operation, and can realize the reduction of cost.
Description of drawings
Fig. 1 is the figure of formation that the PQS valve of the invention process form 1 is shown.
The figure suitable when Fig. 2 supplies with the position for electromagnetic proportional valve is in Fig. 1.
Fig. 3 is the time diagram that the variation of the supply flow of working oil in closing cylinder when action that makes injection molding machine and supply pressure is shown.
Fig. 4 is for illustrating the performance plot of the dependency relation of the supply flow of the control signal (current value) that is input to electromagnetic proportional valve and working oil and supply pressure contrastively with conventional example.
Fig. 5 is the figure suitable with Fig. 1 of form of implementation 2.
Fig. 6 is the figure suitable with Fig. 1 that an example of existing circuit apparatus for hydraulic is shown.
Embodiment
Below, describe form of implementation of the present invention with reference to the accompanying drawings in detail.In this form of implementation, circuit apparatus for hydraulic of the present invention is adapted to the servovalve device of the oil hydraulic cylinder that drives injection molding machine etc.
Form of implementation 1
Fig. 1 illustrates pressure flow servovalve device 2 (to call the PQS valve in the following text), this PQS valve 2 is connected to the oil hydraulic circuit 1 of the main frame of injection molding machine etc., supply with working oil to not shown actuators such as oil hydraulic cylinder, simultaneously, adjust its supply flow Q and supply pressure P, control this actuator movement speed and be used as power.Be connected to the A mouth of main frame oil hydraulic circuit 1, T mouth and the Y mouth that is connected to the P mouth of pump 3 and is connected respectively to fuel tank 4 in these PQS valve 2 settings, the way of the supply passage 5 of working oil, be provided for adjusting the electromagnetic proportional valve 6 of its supply flow from the P mouth to the A mouth, simultaneously, configuration pressure difference compensation valve 7, this pressure difference compensation valve 7 is accepted pilot pressure respectively from the upstream side 5a of this electromagnetic proportional valve 6 and the supply passage of downstream side 5b, its differential pressure is roughly definitely from the supply passage 5a of upstream side makes working oil be bypassed to fuel tank 4.
In addition, the working hydraulic pressure P of the supply passage 5b in these PQS valve 2 configuration detection electromagnetic proportional valves 6 downstream sides and export the pressure transducer 10 of electrical signal and detect electromagnetic proportional valve 6 valve rod 6a the position and export the position transducer 11 of electrical signal; In addition, Configuration Control Unit 12, described controller 12 is accepted from the signal of these each sensor 10,11 outputs, make the supply flow Q of the working oil that supplies to main frame oil hydraulic circuit 1 and the position that supply pressure P becomes the valve rod 6a of command value Qi, the above-mentioned electromagnetic proportional valve 6 of Pi ground feedback control respectively, the i.e. aperture of electromagnetic proportional valve 6.
In detail, the control signal (electric current) of above-mentioned electromagnetic proportional valve 6 origin self-controllers 12 makes solenoid 6b start, the pushing elastic force of resistance spring 6c, the position of control valve rod 6a, switch to working oil supply to host computer side the supply position, discharge the drain position of working oil and stop the stop position of the row of giving of this working oil any from host computer side, simultaneously, in this supply position or drain position continuously Control work oil pass through basal area.In addition, as shown in the figure, the valve rod 6a of electromagnetic proportional valve 6 by spring 6c towards drain position be pushed to the right side of figure, at this drain position, electromagnetic proportional valve 6 is closed the supply passage 5a of upstream side, simultaneously, make the supply passage 5b in downstream side be communicated to discharge route 13, the working oil of host computer side is turned back to fuel tank 4.At this moment, control the basal area of passing through of oil return continuously by the continuous variation of the position of valve rod 6a.
In addition, as shown in Figure 2, when the elastic force by the start of solenoid 6b resistance spring 6c makes valve rod 6a move towards the left side of figure and becomes when supplying with the position, electromagnetic proportional valve 6 is closed discharge route 13, simultaneously, the upstream side and the downstream side of supply passage 5 are communicated with, will supply to host computer side from the working oil that pump 3 is discharged.At this moment, by the continuous variation of the position of valve rod 6a the basal area of passing through of working oil is also changed continuously, the supply flow Q to the working oil of host computer side is controlled continuously from pump 3.In addition, when valve rod 6a was in the intermediate stop position of above-mentioned supply position and drain position, electromagnetic proportional valve 6 was closed upstream side and the downstream side and the discharge route 13 of supply passage 5 respectively.
For the installation of position transducer 11 at above-mentioned electromagnetic proportional valve 6, sensor output vanishing when the valve rod 6a of this electromagnetic proportional valve 6 is in the stop position of central authorities, when valve rod 6a is in the supply position on figure right side, change in location by this valve rod 6a increases the basal area of passing through of working oil, on the occasion of sensor output increase, and when valve rod 6a was in the drain position in figure left side, along with the variation of the position of this valve rod 6a increases the area that passes through of working oil, the sensor output of negative value reduced.
Above-mentioned pressure difference compensation valve 7 is the valve body 7a that is made of lifting head etc. to be applied the safety valve of elastic force by spring 7b (spring component) towards cutting out side, at the branched bottom 14 from the supply passage 5a branch of upstream side, above-mentioned relatively discharge route 13 makes this branched bottom 14 bypass ground configuration.Promptly, to be connected to same side from the control channel 15 in the downstream side of the supply passage 5b branch in downstream side at the valve body 7a of pressure difference compensation valve 7 with spring 7b, close the pilot pressure that a side joint is subjected to its downstream side at valve body 7a, and by above-mentioned branched bottom 14 hydraulic pressure (upstream side pilot pressure) of upstream side supply passage 5a is received the side of opening of valve body 7a at opposition side.
Above-mentioned pressure difference compensation valve 7 is compared with the pushing force that is acted on valve body 7a by the downstream side pilot pressure in the pushing force that is acted on valve body 7a by the upstream side pilot pressure, open start when bigger than the elastic force of spring 7b, by branched bottom 14 that the working oil of upstream side supply passage 5a is logical other to discharge route 13.As the upstream side pilot pressure is descended, then valve body 7a closes, the bypass of working oil is interrupted, the upstream side pilot pressure rises once more.The on-off action of such valve body 7a carries out repeatedly, thereby the front and back differential pressure of electromagnetic proportional valve 6 is kept necessarily substantially.By such front and back differential pressure of compensation electromagnetic Proportional valve 6 definitely, thereby make the aperture that is communicated to the electromagnetic proportional valve 6 of downstream side supply passage 5b from upstream side supply passage 5a, promptly have the corresponding relation certain, thereby can obtain the effective supply flow according to the valve rod position with the effective supply flow with the corresponding valve rod position of basal area of passing through of working oil.
In above-mentioned downstream side control channel 15, configuration simultaneously, at middle the be connected branched bottom 15a of this throttle orifice 17 with pressure difference compensation valve 7, is disposed safety valve 18 (control safety valve) at this branched bottom 15a to the mobile throttle orifice 17 that carries out throttling of working oil.This safety valve 18 is opened start when high in become setting pressure than spring of the hydraulic pressure of branched bottom 15a, make the hydraulic pressure unloading of downstream side control channel 15 by branched bottom 15a, produce the front and back differential pressure of throttle orifice 17 thus, the hydraulic pressure of downstream side control channel 15 descends, and pressure difference compensation valve 7 starts work.By the start of opening of this pressure difference compensation valve 7, the working oil of supply passage 5 is discharged to fuel tank 4 from the T mouth.That is, above-mentioned pressure difference compensation valve 7 has the function as the open hydraulic pressure of so-called controlling type safety valve when the hydraulic pressure of supply passage 5 excessively rises and the collaborative starts of safety valve 18.
In addition, above-mentioned throttle orifice 17 is for for example having the circular cross section of the about 1mm of diameter, the working oil of downstream side control channel 15 mobile carried out throttling, apply and pass through resistance, thereby the on-off action of the valve body 7a of pressure difference compensation valve 7 is applied the buffering of appropriateness, make the action stabilization of this pressure difference compensation valve 7, like this, also have the function that the vibration of the flow of the working oil that suppresses supply passage 5 and pressure reduces.
Above-mentioned controller 12 is, read in the electronics mode by the CPU time lag in accordance with regulations and is stored in the digital controller that the control program in the not shown storage is carried out, and has pressure divergence operational part 12a and flow deviation operational part 12b; This pressure divergence operational part 12a is according to from the signal of pressure transducer 10, obtains the supply pressure P (enforcement supply pressure) to the reality of the working oil of host computer side, from pressure instruction value Pi (goal pressure) it carried out subtraction, calculates pressure divergence; Equally, this flow deviation operational part 12b is according to the signal from position transducer 11, obtain supply flow Q (enforcement supply flow), it is carried out subtraction, calculate flow deviation from flow instruction value Qi (target flow) to the reality of the working oil of host computer side.In other words, in the storage of controller 12, store the functional programs that realizes above-mentioned pressure divergence operational part 12a and flow deviation operational part 12b by software.
In addition, at above-mentioned controller 12 PQ selection portion 12c is set, pressure divergence and flow deviation that this PQ selection portion 12c contrast is calculated respectively by above-mentioned pressure divergence operational part 12a and flow deviation operational part 12b, select smaller value wherein, then calculate the target aperture of electromagnetic proportional valve 6, the i.e. position of valve rod 6a according to the deviation of selecting by pid control law.From accepting from the current driver 12d of the output of this PQ selection portion 12c, the solenoid 6b of electromagnetic proportional valve 6 applies the electric current of the target aperture that is used to move to this electromagnetic proportional valve 6 relatively.
The calculation process of being undertaken by above-mentioned PQ selection portion 12c is also realized by the enforcement of the control program that is stored in storage, the side that the value in selection pressure deviation and the flow deviation is less.Specifically, as pressure divergence and flow deviation all be on the occasion of, then select the less side of absolute value, in addition, as the either party in these two deviations be on the occasion of and also the opposing party be negative value, then select a side of negative value.And then, all be negative value as pressure divergence and flow deviation, then select the big side of absolute value.In other words, the control logic of above-mentioned PQ selection portion 12c is judged as hazardous condition with the state that effective supply flow Q or effective supply pressure P surpass command value Qi, Pi, judge the degree that it is dangerous from each deviation of flow and pressure, carry out the control of electromagnetic proportional valve 6 according to the bigger side's of hazard level deviation.
The action of PQS valve
Below, the action of the PQS valve 2 of formation as described above is described.
For example, carry out moving and during the oil hydraulic cylinder start of matched moulds, electromagnetic proportional valve 6 being moved to supply with the position of metal pattern, will supply to host computer side from the working oil that pump 3 is discharged when in mold closing mechanism, making as the injection molding machine of main frame.At this moment, before cylinder arrives stroke terminal, generally pressure instruction value Pi is set at the value bigger than the effective supply pressure P of necessity, so, controller 12 makes electromagnetic proportional valve 6 start work, surpass flow instruction value Qi up to effective supply flow Q, keep substantially under certain state by the function of pressure difference compensation valve 7 in the front and back of this electromagnetic proportional valve 6 differential pressure, make supply oil mass to host computer side become the cardinal principle suitable and feedback control (flow control mode) is carried out in the position of valve rod 6a a certain amount ofly with flow instruction value Qi.Like this, as shown in Figure 3, effective supply flow Q is suitable with flow instruction value Qi substantially, the action of oil hydraulic cylinder constant speed.
At this moment, the valve rod position of electromagnetic proportional valve 6 is detected by position transducer 11, carries out the feedback control based on its testing result, so the precision of the control of electromagnetic proportional valve 6 and the flow control of working oil is high.Promptly, the attraction force characteristic of solenoid 6b is with respect to the nonlinear characteristics of the current value that applies, hysteresis, deviation etc., by revising fully based on the feedback control from the signal of position transducer 11, like that, the static characteristic of flow control increases substantially shown in solid line among Fig. 4 (a).In addition, owing to be feedback control, so, compare with open type control, can further improve the movement speed of valve rod 6a, also can improve the responsiveness of flow control thus.
In addition, in above-mentioned flow control mode, remainder from the working oil that pump 3 is discharged is by function bypass under certain differential pressure of pressure difference compensation valve 7, the load of host computer side makes the head pressure of pump 3 rest on high slightly degree relatively thus, so, can alleviate the operating load of pump 3, realize energy-conservationization.
After this, the oil hydraulic cylinder of main frame reaches stroke terminal, as not being moved further (moment t1 of above-mentioned Fig. 3), begins thus, and the pressure P of the downstream side supply passage 5b of PQS valve 2 slowly rises, and this pressure P is detected by pressure transducer 10, feeds back to controller 12.When its detected pressures P Overpressure of a safety valve command value Pi (moment t2 of figure), operation values by the PQ selection portion 12c selection pressure deviation operational part 12a of controller 12 is a pressure divergence, makes supply pressure P and pressure instruction value Pi to host computer side as one man carry out feedback control (pressure control mode) to the aperture of electromagnetic proportional valve 6 according to this pressure divergence.
At this moment, to the supply flow Q of host computer side is not zero immediately, at first, the valve rod 6a that is in the electromagnetic proportional valve 6 of supplying with the position slowly moves, and the basal area of passing through of working oil is carried out throttling, and is such as shown in the figure, the supply flow Q of working oil slowly reduces (t2～t3), in addition, this electromagnetic proportional valve 6 switches to stop position, and supply flow Q becomes zero (t3).During this, working oil continues to supply to oil hydraulic cylinder, so the pressure ( P) of oil hydraulic cylinder becomes maximum when supply flow Q is zero.After this, the valve rod 6a of electromagnetic proportional valve 6 is moved further, and switches to drain position, discharges working oil from oil hydraulic cylinder, and at this moment, pressure P drops to pressure instruction value Pi, here stable (t4).In fact, corresponding to leakage, carry out repeatedly from electromagnetic proportional valve 6 to the supply of the working oil of host computer side with stop from the working oil of main frame oil hydraulic circuit.
In such pressure control mode, same with above-mentioned flow control mode, as illustrating, the solid line among Fig. 4 (b) improves static characteristic by feedback control.In addition, under pressure control mode, as described above electromagnetic proportional valve 6 is switched to drain position, thereby can eliminate minimum pilot pressure (Pmin), supply pressure P is controlled to 0 point to the supply pressure P of host computer side.
Therefore, PQS valve 2 (circuit apparatus for hydraulic) according to this form of implementation 1, append the drain position that to discharge working oil from host computer side in adjustment to the electromagnetic proportional valve 6 of the supply flow of the working oil of main frame oil hydraulic circuit 1, simultaneously, the pressure transducer 10 of pressure P of the supply passage 5b in the downstream side of detecting this electromagnetic proportional valve 6 is set, position transducer 11 with the valve rod position of detecting electromagnetic proportional valve 6, according to these sensors 10,11 output signal control valve rod position, thereby supply flow Q and supply pressure P to the working oil that feeds to host computer side carry out feedback control, so it is controlled to be that the dynamic response of static characteristics such as linear performance and hysteresis and responsiveness etc. is greatly improved than in the past.
Like this,, can obtain high reproducibility simultaneously, the increasing substantially of the quality that can realize thus being shaped corresponding to the molding condition of the different corresponding wide ranges of the shape of profiled member and material in the occasion that for example above-mentioned PQS valve 2 is applicable to injection molding machine.
In addition, at electromagnetic proportional valve 6 drain position is set as described above, according to signal its aperture is carried out feedback control from pressure transducer 10, so, for supply pressure P to host computer side, eliminate its minimum pilot pressure Pmin, can proceed to the control of zero pressure, like this, also can be fully corresponding to the requirement of the low pressure matched moulds operation of injection molding machine etc.
And, the formation of above-mentioned PQS valve 2 is compared with the flow rate regulating valve device (with reference to Fig. 6) of band ratio electromagnetic valve in the past, need pressure transducer 10 and position transducer 11, on the other hand, but do not need needed pressure proportioning valve 8 and current drives loop 9 correspondingly in the past, so the cost increase of sensor 10,11 is cancelled.
Form of implementation 2
Fig. 5 illustrates the formation of the PQS valve 20 (circuit apparatus for hydraulic) of the invention process form 2.The PQS valve 2 of this PQS valve 20 and the form of implementation 1 only formation of the throttle orifice of downstream side control channel 15 is different, and formation in addition is identical with above-mentioned form of implementation 1, below identical components is adopted identical symbol, omits its explanation.The action of the PQS valve 20 of this form of implementation 2 relative its valve body 7a when the switching start of pressure difference compensation valve 7 and above-mentioned form of implementation 1 similarly apply the buffering of appropriateness, simultaneously, only make the further speed up of the start speed of closing of valve body 7a.
Promptly, in above-mentioned form of implementation 1, the source takes place in the differential pressure of the throttle orifice 17 of downstream side control channel 15 when working as the controlling type safety valve with safety valve 18 and pressure difference compensation valve 7, simultaneously, the action of the valve body 7a of pressure difference compensation valve 7 is applied the buffering of appropriateness, make this valve body 7a the action stabilization work, but the action of result valve body 7a when the closing motion of this pressure difference compensation valve 7 latens, as described above, even become the movement speed of the valve rod 6a that improves electromagnetic proportional valve 6, the response that increases to the flow of host computer side is the reason of speed up not also.
Be elaborated with regard to this point below.In the PQS of form of implementation 1 valve 2,, need to change the aperture that flow instruction value Qi increases electromagnetic proportional valve 6, and increase from the flow of pump 3 to the working oil of electromagnetic proportional valve 6 in order to increase the supply flow of working oil when the flow control mode to host computer side.At this moment, increase the aperture that is in the electromagnetic proportional valve 6 of supplying with the position according to the signal that comes self-controller 12 earlier, when the front and back differential pressure that makes this electromagnetic proportional valve 6 thus diminishes for the moment, the valve body 7a that accepts the pressure difference compensation valve 7 of upstream side and downstream side pilot pressure is respectively closed.
At this moment, in downstream side control channel 15, working oil flows to pressure difference compensation valve 7, but the power of the valve body 7a of shut off differential pressure recuperation valve 7 is the elastic force degree of spring 7b just at most, so, when carrying out throttling by 17 pairs of working oil of throttle orifice mobile as described above, the action of closing of valve body 7a latens, and can not promptly make the working oil deflection electromagnetic proportional valve 6 of discharging from pump 3.That is, even but self speed up is made in starting of electromagnetic proportional valve 6, can not increase as desired from this supply flow, so flow responds and still has room for improvement to the working oil of host computer side.
Consider such transient phenomenon, in the PQS of this form of implementation 2 valve 20, such as shown in the figure, in downstream side control channel 15, in series configuration effort oil pass through basal area than the big first segment discharge orifice 21 of the throttle orifice 17 of form of implementation 1 and throttle degree than this first segment discharge orifice the last 21, promptly by the second little throttle orifice 22 of basal area; Simultaneously, configuration allows that working oil flows to pressure difference compensation valve 7 but stops the one-way valve 24 of its adverse current in the bypass passageways 23 of this second throttle orifice 22 of bypass.
Say that more specifically above-mentioned first segment discharge orifice 21 for example has the circular cross section of the about 2mm of diameter, in addition, above-mentioned second throttle orifice 22 has the circular cross section with about 1mm of throttle orifice 17 same diameter of above-mentioned form of implementation 1.When working oil through downstream side control channel 15 when pressure difference compensation valve 7 flows to downstream side supply passage 5b, flowing of this working oil by first and second both sides' throttle orifice 21,22 throttlings, particularly from second throttle orifice 22 accept with the occasion of above-mentioned form of implementation 1 same pass through resistance.On the other hand, when working oil through downstream side control channel 15 when pressure difference compensation valve 7 flows, flowing of this working oil only accepted by resistance from the more weak first segment discharge orifice 21 of relative throttle degree, the mobile speed of passing through uprises relatively.
Thus, when in order to increase working oil and when increasing the aperture of electromagnetic proportional valve 6 to the supply flow of host computer side, in downstream side control channel 15,, correspondingly make the valve body 7a of pressure difference compensation valve 7 carry out closing motion with more speed to fast than form of implementation 1 of flowing of the working oil that flows of pressure difference compensation valve 7.For this reason, the delay of opening start of closing the relative electromagnetic proportional valve 6 of start of pressure difference compensation valve 7 alleviates significantly, and the flow that flows to the working oil of electromagnetic proportional valve 6 from pump 3 increases immediately, so, further improve its responsiveness in the time of can increasing at the supply flow of working oil.
And, when the valve body 7a of pressure difference compensation valve 7 opens start, accept the relatively large resistance that passes through by the working oil of downstream side control channel 15 from first and second throttle orifices 21,22, so, relatively this valve body 7a applies the buffering of appropriateness, and this is identical with above-mentioned form of implementation 1.
In addition, when reducing working oil, reduce the aperture ground control of electromagnetic proportional valve 6 by controller 12 to the supply flow of host computer side, but this moment electromagnetic proportional valve 6 the hydraulic pressure of upstream side sharply increase, act on the valve body 7a of pressure difference compensation valve 7 by branched bottom 14.At this moment, the start of opening along with valve body 7a, side supply passage 5b is mobile downstream from pressure difference compensation valve 7 for working oil in downstream side control channel 15, flowing of this working oil accepts to pass through resistance from first and second throttle orifices 21,22, but because high to valve body 7a effect as described above upstream side pilot pressure, so enough height are made in starting of this valve body 7a, as a result, operating lag does not become problem when supply flow reduces.
Therefore, PQS valve 20 according to this form of implementation 2, can obtain the action effect same with above-mentioned form of implementation 1, simultaneously, by two throttle orifices 21,22 and the one-way valve 24 that are disposed at downstream side control channel 15, guarantee the stability of the action of pressure difference compensation valve 7, simultaneously, what can further make this valve body 7a closes the action speed up, like this, when when host computer side increases the supply flow of working oil, can fully improve its responsiveness.
Like this, be applicable to the occasion of injection molding machine, and comparing in the past, carrying out the shaping of the profiled member of thin-walled easily, and, can shorten reducing cost by the shaping circuit.For this point, shaping thin wall spare by the injection molded acquisition, may cool off on the way that the resin of injection enters into mould inside and solidify, in order to prevent this phenomenon, require special flow at a high speed to increase response, so, effective especially for improving responsiveness as the PQS valve of this form of implementation.
Other form of implementation
The invention is not restricted to the formation of above-mentioned form of implementation 1,2, also comprise various actual formation in addition.That is, in above-mentioned form of implementation 1,2, all with circuit apparatus for hydraulic of the present invention as a PQS valve 2,20, the formation of the type combination valve that do not need necessarily oil hydraulic circuit of the present invention to be formed as one.In addition, main frame is not limited to injection molding machine, applicable to the various mechanical devices with hydraulic actuators such as oil hydraulic cylinder and oil hydraulic motors.
In addition, the formation of controller also is not limited to the controller 12 of above-mentioned each form of implementation, for example, also can use formations such as comparator exclusive disjunction amplifier to have the analog controller of said function.
In addition, electromagnetic proportional valve of the present invention is not limited to above-mentioned each form of implementation, also can be have the A mouth, P mouth, and the amount of restriction of the T mouth throttle valve that can change by automatically controlled mode.That is, can also can be the controlling type that valve rod is moved for directly push the direct-acting type of valve rod 6a by solenoid 6b.In addition, the occasion of controlling type, control valve can be the type of usage ratio valve and uses in the type of servovalves such as nozzle flapper any.In addition, the present invention is owing to be provided with the valve rod position transducer, so, also electromagnetic proportional valve 6 and servovalve can be replaced.
As described above, circuit apparatus for hydraulic of the present invention can make the action speed up and the raising control accuracy of the actuator of main frame, simultaneously, zone that can pilot pressure can be expanded to zero point substantially, so, when being used for the hydraulic actuator of drive mechanism, has very excellent characteristic, particularly can increase substantially forming quality in the occasion that is applicable to injection molding machine, simultaneously cycle time can be shortened, and also can satisfy fully the requirement of low pressure matched moulds operation that in the past can not be corresponding, so, the possibility height that utilizes on the industry.

Claims (5)

1. a circuit apparatus for hydraulic (2,20), the electromagnetic proportional valve (6) that the supply flow of working solution is adjusted is set in the supply passage (5) of the working solution that feeds to hydraulic actuator, simultaneously, pressure difference compensation valve (7) is set, and described pressure difference compensation valve (7) is accepted pilot pressure from the upstream side of this electromagnetic proportional valve (6) and downstream side respectively and is made its differential pressure make working solution be bypassed to fuel tank (4) for the supply passage (5a) from upstream side definitely; Above-mentioned electromagnetic proportional valve (6) at least also has the drain position of discharging working solution from this actuator except having to above-mentioned actuator is supplied with the supply position of working solution; It is characterized in that:
Have the working fluid pressure of the supply passage (5b) that detects above-mentioned downstream side and export the pressure transducer (10) of electrical signal; Detect the valve rod position of above-mentioned electromagnetic proportional valve (6) and export the position transducer (11) of electrical signal; And controller (12), described controller (12) is accepted respectively from the signal of above-mentioned pressure transducer (10) and position transducer (11) output, and makes the supply flow of the working solution that feeds to above-mentioned actuator and the aperture that supply pressure becomes the control command value ground above-mentioned electromagnetic proportional valve of feedback control (6).
2. circuit apparatus for hydraulic according to claim 1 (2,20) is characterized in that: above-mentioned controller (12) has flow deviation operational part (12b), pressure divergence operational part (12a), PQ selection portion (12c) and current driver (12d);
This flow deviation operational part (12b) simultaneously, deducts this effective supply flow, calculated flow rate deviation from the flow instruction value according to the effective supply flow of obtaining from the signal of above-mentioned position transducer (11) to the working solution of actuator;
This pressure divergence operational part (12a) simultaneously, deducts this effective supply pressure, calculating pressure deviation from the pressure instruction value according to the effective supply pressure of obtaining from the signal of above-mentioned pressure transducer (10) to the working solution of actuator;
This PQ selection portion (12c) is selected the deviation of the less side of numerical value in above-mentioned flow deviation and the pressure divergence, according to the target valve rod position of the above-mentioned electromagnetic proportional valve of the deviation calculation of this selection (6);
This current driver (12d) applies electric current at the solenoid (6b) of the valve rod (6a) of above-mentioned electromagnetic proportional valve (6), to become the target location that is calculated by above-mentioned PQ selection portion (12c).
3. circuit apparatus for hydraulic according to claim 1 and 2 (2,20), it is characterized in that: above-mentioned pressure difference compensation valve (7) has the spring (7b) that applies elastic force towards a side of cutting out this valve body (7a), be subjected to pilot pressure at a side joint of closing this valve body (7a) from the downstream side of above-mentioned electromagnetic proportional valve (6), on the other hand, a side joint of opening at valve body (7a) is subjected to the pilot pressure from the upstream side of electromagnetic proportional valve (6);
At control channel (15) configuration in the downstream side that pilot pressure is guided to above-mentioned pressure difference compensation valve (7) from the downstream side of above-mentioned electromagnetic proportional valve (6) the mobile throttle orifice (17) that carries out throttling to working solution, and then, be connected control safety valve (18) with control channel (15) between the pressure difference compensation valve (7) at this throttle orifice (17).
4. circuit apparatus for hydraulic according to claim 3 (20) is characterized in that: in series dispose first segment discharge orifice (21) and second throttle orifice (22) stronger than its throttle degree in above-mentioned downstream side control channel (15);
In the bypass passageways (23) of above-mentioned second throttle orifice of bypass (22), configuration allows that working solution flows but one-way valve (24) that its counter current is stoped to above-mentioned pressure difference compensation valve (7).
5. circuit apparatus for hydraulic according to claim 1 (20) is characterized in that: above-mentioned hydraulic actuator is used to drive injection molding machine.
CNB028023161A 2001-07-05 2002-06-13 Hydraulic circuit device Expired - Fee Related CN1274965C (en)

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JP2001204580A JP3783582B2 (en) 2001-07-05 2001-07-05 Hydraulic circuit device
JP204580/2001 2001-07-05

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CN1274965C true CN1274965C (en) 2006-09-13

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KR20030029160A (en) 2003-04-11
CN1464945A (en) 2003-12-31
JP2003021103A (en) 2003-01-24
EP1403528A1 (en) 2004-03-31
KR100781029B1 (en) 2007-11-29
EP1403528A4 (en) 2011-06-29
TW552354B (en) 2003-09-11
WO2003004879A1 (en) 2003-01-16
JP3783582B2 (en) 2006-06-07

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