CN1018378B - Combined decompressing and speed-regulating valve by hydroelectric proportion - Google Patents

Abstract

The present invention relates to a device which can carry out continuous stepless control to the pressure and the flow quantity of fluid. The present invention is provided with a pressure sensor [4] on the outlet of a common proportional throttle valve [2] to detect the pressure of a cavity. Consequently, the closed loop control of output pressure is realized, control precision is raised, and minimal controlled pressure is zero pressure. Furthermore, the same throttle valve is used, and the valve has a flow control function by regulating the opening quantity of the throttle valve according to a pressure correcting method through using the pressure sensor to detect load pressure. The function of a proportional pressure-reducing valve and a proportional speed regulating valve can be performed by only using the proportional throttle valve.

Description

Combined decompressing and speed-regulating valve by hydroelectric proportion

The invention belongs to the device of fluid pressure in hydraulic transmission and the control system, the control of flow realization continuous ratio.

The method of in the flow control system pressure and flow being carried out continuous stepless control has two kinds.A kind of positive displacement proportional controlling means that is called, another kind is called the throttle type proportional controlling means.Adopt positive displacement method no matter pilot pressure or flow, finally all be summed up as the controlled variable pump delivery, so realized utilizing a cover control gear now, mixed the function that pressure and displacement transducer just can all be controlled the delivery pressure of pump and flow and even power.For the throttle type proportional control element, because it is available at present also not play the dynamic flow sensor of throttling action as pressure transducer, so utilizing existing control principle is only can't construct with a throttle element, be equipped with the Proportional valve that pressure and displacement transducer just can carry out compound control to its output flow and pressure again.When controlling, fluid pressure and flow just must adopt a proportional pressure valve and a proportional velocity regulating valve, totally two valves.

The present invention proposes a kind of new flow control principle just for this reason, i.e. " pressure reduction variation-bit shift compensation before and after output flow-restriction " method.Use this principle and only realized a purpose on common proportional throttle valve, being equipped with pressure transducer with a throttle element energy pilot pressure and flow.Now this new flow control principle is described as follows:

The flow that flows to its outlet A from throttle valve import P is Q=KX $\sqrt{\mathrm{\Delta P}}$ (wherein K is and flow coefficient, the relevant constant of valve port area gain, and X is a valve port opening, and △ P is that throttle valve is imported and exported the pressure reduction between P, the A).The method of control flow rate is now: make X and input quantity linear, and manage simultaneously to guarantee that △ P does not change with the variation of induced pressure.So just must connect again one before or after a throttle valve so-called flow transducer of the Fixed differential reducing valve that plays the level pressure effect or two logical plug-in types makes the structure complicated of valve.New method supposition, Q _o=KX $\sqrt{\mathrm{△P}{}_o}$ Be a standard flow, (△ P _oA minimum control pressure reduction for artificial regulation), as seen as △ P _oWhen constant, Q _oWill be with X linear change.But when the constant and △ P of X changes, Q _oWill depart from reference value and become Q ₁=KX $\sqrt{\mathrm{△P}{}_1}$ , but that this is a system is undesirable, so should make Q ₁=KX $\sqrt{\mathrm{△P}{}_1}$ ＝K·X· $\sqrt{\mathrm{△P}{}_o}$ , $X_1\mathrm{=X}\sqrt{\mathrm{\Delta P}{}_0\mathrm{/\Delta P}{}_1}$ As seen as long as make valve port opening and pressure difference before and after the valve satisfy following formula and concern the output flow of valve is not changed with induced pressure.As long as this detect △ P at any time and calculate X with an arithmetic mean unit simulation or numeral by following formula with pressure transducer ₁At any time input quantity correction is got final product, the pressure transducer that is adopted also just in time can be used to pilot pressure.

Purpose of the present invention is exactly only to use a proportional throttle valve, makes it have the compound control function of pilot pressure and flow by using new flow control principle.

Below in conjunction with accompanying drawing principle of the present invention and structure are described in further detail.

Fig. 1 is the structural drawing of the designed pressure flow control valve of the inventor, is called combined decompressing and speed-regulating valve by hydroelectric proportion.

Combined decompressing and speed-regulating valve by hydroelectric proportion is by adjuster [1], proportional throttle valve [2], and flow correction arithmetic unit [3], pressure sensor [4] and [5] form.

Wherein the effect of proportional throttle valve [2] is to convert the signal of telecommunication that adjuster is supplied with to it proportional valve port opening X, i.e. the size of restriction between the P-A mouth, and it can To be present employed any proportional throttle valve. The effect of adjuster [1] is: 1. the signal of telecommunication with pressure sensor [4] output compares in subtracter [8] with pressure set points Ups, and the difference is relatively carried out the correction calculations such as ratio, proportional-plus-integral, proportional-plus-integral, differential; 2. according to the size of flow-control setting value Uqs and pressure set points Ups, selection is control flow or controlled pressure, and this selection result is input in the control circuit of proportional throttle valve [2] and goes. Pressure sensor [4] is installed in the runner [6] that is communicated with proportional throttle valve [2] upper outlet A and executing agency [12], its effect is to convert linearly the pressure in this runner to voltage signal, and supply with simultaneously adjuster [1] and flow correction arithmetic unit [3], to pressure with flow is controlled and load pressure is monitored or measures. Pressure sensor [5] is used for detecting the pressure in the runner [7], and it only just needs under this flowpath pressure variation occasion greatly, and in general pressure fixing system, as be equipped with in the system of overflow valve [10], can save this pressure sensor. The effect of flow correction arithmetic unit [3] is pressure difference signal and the flow initial set value Uqso that provides according to pressure sensor [4], [5], flow-control new principle by " pressure reduction variation-bit shift compensation before and after output flow-restriction " calculates revised flow setting value Uqs, and this value is input in the adjuster [1].

The course of work of this valve is: at first by adjuster [1] according to the input signal of telecommunication Uqs and the size of Ups, selection is to control to flow or to pressure, and the result is imported in the control circuit of proportional throttle valve. Such as controlled pressure, then (Ups-Upf) this difference plays regulating action, is used for the size of control ratio choke valve opening, because the effect of integral adjustment, makes pressure in the runner [6] with to set value Ups consistent, i.e. Ups-Upf=O during stable state. So constantly change setting value Ups, the output pressure of valve just changes with Ups, always and be consistent with Ups during stable state, Here it is to the control of pressure Process processed.

If output flow is controlled, the control signal of then supplying with proportional throttle valve is Uqs, by aforesaid flow-control new principle as can be known, and because Uqs at this moment satisfies relational expression $X_1\mathrm{=X}\sqrt{\mathrm{\Delta P}{}_0\mathrm{/\Delta P}{}_1}$ So no matter how load pressure changes, the output flow of valve is all the time linear with input signal Uqso, and have level etc. discharge characteristic. At this moment pressure signal Ups is with the maximum working (operation) pressure (MWP) of initialization system.

More than be the structure of this valve and to the control procedure of pressure and flow, its major advantage is as follows:

1, only just realized the control of pressure and two fluid parameters of flow has been simplified the structure of existing control valve greatly, and reduced cost with a proportional throttle valve.

2, electric closed loop control has improved the control accuracy to pressure and flow greatly.Only this valve just can carry out continuously the pressure and the speed of actuator, control accurately in hydraulic system, and antipollution, can replace existing proportional pressure-reducing valve and two logical proportional velocity regulating valves, be widely used in press, in the multiple hydraulic host machine such as engineering machinery.

3, this valve also provides most convenient, the simplest, motor reliable tool translation interface for the computer control of hydraulic system.

Below in conjunction with Fig. 1, the present invention is further described by embodiment.

Proportional throttle valve adopts the displacement-force feedback type proportional throttle valve of guide's control, and latus rectum is 16mm.Regulator [1] selects for use proportional-plus-integral to add the correction adjustment algorithm of differential, and the circuit that its selection function is made up of diode is finished.It is the resistance strain type pressure sensor of 0-35MPa that measuring range is selected in pressure transducer [4], [5], and has integrated preamplifier stage.The analog circut that the flow correction arithmetic mean unit is made up of linear operational amplifier is realized.

Claims (2)

1, a kind of combined decompressing and speed-regulating valve by hydroelectric proportion, it includes proportional throttle valve [2], it is characterized in that having set up regulator [1], flow correction arithmetic mean unit [3], pressure transducer [4] and [5]; Pressure transducer [4] is installed in the runner [6] that is communicated with proportional throttle valve [2] upper outlet A and actuator [12]; The output voltage signal Upf of pressure transducer [4] is input in regulator [1] and the flow correction arithmetic mean unit [3] by lead; Pressure transducer [5] is installed in the runner [7] of the outlet, actuator [11] and the relief valve [10] that are communicated with proportional throttle valve [2] upper inlet P, oil pump [9]; The output voltage signal Up of pressure transducer [6] is input in the flow correction arithmetic mean unit [3] by lead; The import P of proportional throttle valve [2] is communicated with runner [7], and its outlet A is communicated with the import of the actuator that is controlled [12] by runner [6]; In the flow correction arithmetic mean unit [3] the revised signal Ugs of initial flow setting value Ugso is input in the regulator [1] through lead; The output voltage signal of regulator [1] is controlled the size of its opening amount in lead is input to current controller in the proportional throttle valve [2].

2, combined decompressing and speed-regulating valve by hydroelectric proportion according to claim 1 is characterized in that can removing pressure transducer [5] under the constant substantially situation of pressure in runner [7].