EP3093504B1 - Pressure controlled two-way flow control valve for hydraulics applications and valve assembly with a corresponding two-way flow control valve - Google Patents

Description

The present invention relates to pressure controlled 2-way flow control valves for hydraulic applications and valve assemblies for hydraulic applications having a corresponding 2-way flow control valve.

In demanding hydraulic circuits such as cranes, concrete boom and other lifting and manipulating devices, proportional directional shifters are generally used to enable simultaneous operation of multiple consumers. In practice, it is often necessary to control several consumers completely individually and simultaneously, which should be done as independent of load pressure as possible.

From the product program 2011 of HAWE is on the pages 98 to 101 a proportional directional spool type PSL with connection blocks and attachment block known. Regarding Fig. 1a schematically a hydro circuit is shown, in which two known proportional directional spool type PSL, denoted in the figure by the reference numerals PS1, PS2, with a suitable terminal block for a constant pump 1 for the operation of two consumers V1, V2 are provided. A supply pressure P output from constant-displacement pump 1 is supplied by a supply line 6 to a plurality of highly schematically represented consumers V1, V2, eg hydraulic cylinders, via the respective proportional directional spools PS1, PS2 in order to drive the consumers V1, V2. The inflow in front of the proportional directional slides PS1, PS2 is controlled in each case by a pressure-controlled 2-way flow control valve 41, 42, which is arranged in the inflow direction in front of the corresponding proportional directional spool PS1, PS2. If at least one of the consumers V1, V2 is to be operated during operation, the associated proportional directional shifter PS1, PS2 is deflected upwards or downwards from the illustrated blocking state, depending on whether a connection A1, A2 connected to the corresponding consumer V1, V2 is present or B1, B2 is to be connected to the supply line 6. About the stroke of the deflection is given by the proportional directional spool PS1, PS2 a volume flow to the respective consumer V1, V2.

Via a corresponding LS line LS1, LS2 (in Fig. 1 shown in dashed lines) a behind the corresponding proportional directional spool PS1, PS2 dropping load pressure to the associated 2-way flow control valve 41, 42 is reported. Furthermore, it is ensured via shuttle valves 2 that the highest load pressure of those reported by the LS lines LS1, LS2 Load pressures (corresponds to the load pressures dropping at the consumers V1, V2) are reported to a circulation regulator 8 of the constant pump system.

The load pressure reported by the LS line LS1 or LS2 to the 2-way flow control valve 41 or 42, acting on the bias of the biasing spring, acting on the direction of the 2-way flow control valve 41 and 42 applied thereto. Further, each 2-way flow control valve 41, 42 is further applied with a pressure signal tapped on the output side of the respective 2-way flow control valve 41, 42 in the control direction (i.e., counteracting the bias) of the respective 2-way flow control valve 41, 42. Each of the 2-way flow control valves 41, 42 is biased by a biasing spring in the up direction, so that the 2-way flow control valves 41, 42 are open in the rest state.

In the equilibrium position, therefore, a certain pressure difference between the tapped LS pressure and a pressure signal corresponding to the tapped output-side pressure of the 2-way flow control valve is established. As a result, changes in the flow rate in the case of springs with a small spring constant or flat spring characteristic are adjusted to a constant value. Accordingly, each of the two-way flow control valve 41, 42 regulates a volume flow through the corresponding proportional displacement valve PS1, PS2 load-independent to a constant value. In other words, if the volumetric flow occurring behind the proportional directional spool PS1 or PS2 drops during operation of the consumer V1 or V2, the pressure difference between the pressure dropping behind the two-way flow control valve 41 or 42 (reported as "p _A ") and the falling behind the proportional directional spool load pressure (which is reported as "p _LS " via the LS line LS1 and LS2 to the 2-way flow control valve 41 and 42), so that a Control piston (not shown) in the 2-way flow control valve 41 and 42 along the open-control direction shifts. The result is that the control piston in the 2-way power latch valve 41 or 42 again sets a balance of power, albeit at a larger throttle cross-section in the 2-way flow control valve 41 and 42, so that the reduction of the flow rate and the pressure difference (p _A - p _LS ). Thus, the volume flow to the consumer and the pressure difference between the pressure provided by the constant-displacement pump 1 and the pressure in the load circuit to the consumer are regulated to a constant value. On the other hand, if the pressure difference (p _A -p _LS ) on the proportional directional spool PS1 or PS2 increases, which corresponds to an increase in the volumetric flow, the 2-way flow control valve is regulated in the direction to until a new equilibrium of forces occurs. In-2-way flow control valve shifts a control piston (not shown) in the Zu-control direction, whereby a throttle cross-section in the 2-way flow control valve 41 and 42 decreases. With decreasing throttle cross section but take the Volume flow and the pressure difference (p _A - p _LS ) again from (the initial increase counteracting), until in turn adjusts a balance of forces.

In Fig. 1b the resulting characteristic of the 2-way flow control valve 41, 42 is shown schematically, in which a volumetric flow Q (along the abscissa in arbitrary units) against a pressure difference Δp (corresponds to a pressure difference pump pressure - p _LS ) (along the ordinate in arbitrary units) is applied. After an initial drive curve section AK, the in Fig. 1b illustrated characteristic curve a control curve section RK with a vertical curve, which means the independence of the volume flow of the pressure difference .DELTA.P when adjusting a balance of forces, since the volume flow in the control curve section is controlled independently of the pressure difference .DELTA.p to a constant value Q ₀ .

Furthermore, the shows DE 10 2012 220 863 A1 a designed as a 2-way flow control valve lowering brake valve according to the preamble of claim 1.

It is desirable to provide a volumetric flow control deviating from the above-described load-independent volumetric flow control, which allows a load-dependent volumetric flow control to improve a variability of hydraulic circuits, depending on the specific application. For example, in some "good feel" applications, it may well be desirable to control the flow rate load-dependent to give a user a "feeling of stress".

It is therefore an object to provide a 2-way flow control valve and a valve assemblies with a corresponding 2-way flow control valves, wherein the flow control is stabilized in the operating points, especially in interaction with other hydraulic controllers, and / or a more accurate flow control in the lower Pressure difference range is enabled.

The foregoing objects and problems are solved in a first aspect of the invention by a pressure controlled 2-way flow control valve for hydraulic applications. According to illustrative embodiments, a first pressure signal can be applied to the 2-way flow control valve via a first output-side tap in the Zu control direction of the 2-way flow control valve and a second pressure signal via an LS pressure message line in the open control direction.

A pressure signal falsifying the first or second pressure signal is applied to the 2-way flow control valve via a second tap in the open or closed control direction, which is effective for at least part of the control stroke of the 2-way flow control valve.

The inventive 2-way flow control valve is characterized in that the falsifying pressure signal is applied only over part of the control stroke of the 2-way flow control valve. Thereby, a partial vaccination of the characteristic of the 2-way flow control valve is achieved, which is effective in at least a certain portion of the control stroke.

Due to the falsifying pressure signal, a vaccination of a characteristic curve provided by the 2-way flow control valve is achieved, so that the characteristic curve of the vaccinated flow control valve in the control curve section has a characteristic from the vertical course (cf. Fig. 1b ) has a different course and, in particular, the volume flow is adjusted as a function of pressure. The vaccination of the 2-way flow control valve leads to a stabilization of the flow control in some operating points, which is particularly advantageous in interaction with other hydraulic controllers.

In a more advantageous embodiment herein, the falsifying pressure signal in the part of the control stroke which picks up the falsifying pressure signal is applied to the 2-way flow control valve via a first nozzle or a first diaphragm in open or closed control direction. Through the first nozzle or first orifice, a degree of vaccination can be easily defined.

In a further illustrative embodiment of the invention, the 2-way flow control valve further comprises a second nozzle or aperture connected in series with the first nozzle or aperture, the adulterated pressure signal being across a control port located between the nozzles or orifices is applied to the 2-way flow control valve. By appropriately formed series connection of two diaphragms, two nozzles or a diaphragm and a nozzle, an advantageous adjustment of the injection pressure is achieved at the 2-way flow control valve.

In a further illustrative embodiment of the invention, the second tap on the 2-way flow control valve is arranged on the input side. This represents a structurally simple way to provide the pressure vaccination.

In one illustrative embodiment herein, the falsifying pressure signal is applied in the open-control direction so that as the difference between the first pressure signal and the second pressure signal increases on the output side, an increasing volume flow adapts to the 2-way flow control valve. A corresponding volume flow control has a dampening effect on pressure fluctuations occurring in the hydraulic system.

In another illustrative embodiment herein, the falsifying pressure signal is applied in the on-control direction so that as the difference between the first pressure signal and the second pressure signal increases on the output side, a decreasing volume flow adapts to the 2-way flow control valve. This can optionally achieve a desired overcompensation. This causes instabilities in the hydraulic system at certain operating points, e.g. in the power limitation range lead to a power limitation of the pump, stabilized.

In a further illustrative embodiment of the present invention, the second tap is arranged on the output side of the 2-way flow control valve and the falsifying pressure signal is applied in the open control direction. As a result, an energy optimization can be achieved such that a relatively small pressure difference is sufficient to control a volume flow to a constant value, whereby the control quality improves and accordingly a more accurate flow control is made possible even at small pressure differences. Furthermore, a volume flow to a predetermined pressure difference is higher than compared to a 2-way flow control valve with a conventional characteristic.

In one illustrative embodiment, the control stroke has a passage section and a blocking section in which no volume flow occurs on the output side of the 2-way flow control valve, wherein the distorting pressure signal in the passage section is applied to the 2-way flow control valve only over part of the control stroke. This allows a vaccination that occurs only over a portion of the control stroke.

In another illustrative embodiment of the invention, the 2-way flow control valve is configured such that the falsifying pressure signal is blocked only over part of the control stroke. As a result, unvaccinated control in a control range is possible. In this case, a pressure-independent volume flow control over a part of the control stroke is maintained.

In a second aspect of the present invention, a valve assembly for hydraulic applications is provided. In illustrative embodiments of the invention, the valve assembly comprises a proportional directional spool for controlling a hydraulic consumer and a 2-way flow control valve according to the first aspect of the invention as described above, wherein the 2-way flow control valve is connected on the output side to the proportional directional spool valve.

In a third aspect of the present invention, a valve assembly for hydraulic applications is provided. In illustrative embodiments of the invention, the valve assembly includes a proportional directional spool for controlling a hydraulic consumer and a 2-way flow control valve according to the first aspect of the invention as described above, wherein the 2-way flow control valve is connected on the input side to the proportional directional spool valve.

In one illustrative embodiment of the second or third aspect, the proportional directional spool is integrated with the 2-way flow control valve in a valve block. This provides an advantageous compact design for valve assemblies according to the second or third aspect.

Fig. 1a

schematisch eine bekannte Ventilanordnung mit 2-Wege-Stromregelventilen;

Fig. 1b

die Kernlinie eines bekannten Stromregelventils schematisch darstellt;

Fig. 2a

schematisch eine Ventilanordnung gemäß einer Ausführungsform der vorliegenden Erfindung darstellt;

Fig. 2b

schematisch eine Kennlinie eines Stromregelventils gemäß einer Ausführungsform der vorliegenden Erfindung darstellt;

Fig. 2c

einen Verlauf einer Durchflussquerschnittfläche des Stromregelventils entlang eines Regelhubs gemäß einer Ausführungsform der vorliegenden Erfindung darstellt

Fig. 3a

schematisch eine Ventilanordnung gemäß einer weiteren anschaulichen Ausführungsform der Erfindung darstellt;

Fig. 3b

schematisch eine Kennlinie eines Stromregelventils gemäß einer weiteren Ausführungsform der vorliegenden Erfindung darstellt;

Fig. 3c

einen Verlauf einer Durchflussquerschnittfläche des Stromregelventils entlang eines Regelhubs gemäß einer Ausführungsform der vorliegenden Erfindung darstellt

Fig. 4a

schematisch eine Ventilanordnung gemäß einer anderen anschaulichen Ausführungsform der vorliegenden Erfindung darstellt;

Fig. 4b

schematisch eine Kennlinie eines Stromregelventils und einen Verlauf einer Durchflussquerschnittfläche des Stromregelventils entlang eines Regelhubs gemäß einer anderen Ausführungsform der vorliegenden Erfindung darstellt; und

Fig. 4c

einen Verlauf einer Durchflussquerschnittfläche des Stromregelventils entlang eines Regelhubs gemäß einer Ausführungsform der vorliegenden Erfindung darstellt.

Further advantageous embodiments of the present invention will be described below with reference to the following figures, wherein:

Fig. 1a

schematically a known valve arrangement with 2-way flow control valves;

Fig. 1b

schematically illustrates the core line of a known flow control valve;

Fig. 2a

schematically illustrates a valve assembly according to an embodiment of the present invention;

Fig. 2b

schematically illustrates a characteristic of a flow control valve according to an embodiment of the present invention;

Fig. 2c

FIG. 5 illustrates a profile of a flow cross-sectional area of the flow control valve along a control stroke according to an embodiment of the present invention. FIG

Fig. 3a

schematically illustrates a valve assembly according to another illustrative embodiment of the invention;

Fig. 3b

schematically illustrates a characteristic of a flow control valve according to another embodiment of the present invention;

Fig. 3c

FIG. 5 illustrates a profile of a flow cross-sectional area of the flow control valve along a control stroke according to an embodiment of the present invention. FIG

Fig. 4a

schematically illustrates a valve assembly according to another illustrative embodiment of the present invention;

Fig. 4b

schematically illustrates a characteristic of a flow control valve and a profile of a flow cross-sectional area of the flow control valve along a control stroke according to another embodiment of the present invention; and

Fig. 4c

FIG. 5 illustrates a profile of a flow cross-sectional area of the flow control valve along a control stroke according to an embodiment of the present invention. FIG.

Hereinafter, various aspects and embodiments of the present invention will be described in more detail with reference to the accompanying drawings.

Fig. 2a schematically shows a valve assembly according to an illustrative embodiment of the invention. The valve assembly includes a valve block 110 and a port block 120 connected to the valve block 110. The connection block 120 has a pilot pressure regulating valve 122 and can be connected to a constant pump system (not shown; Fig. 1a ) or alternatively connected to a control pump system (not shown).

According to the in Fig. 2a 1, the valve block 110 may have a proportional directional spool 112 and a two-way flow control valve 130 arranged in the supply line upstream of the proportional directional spool 112. The proportional directional slide 112 is z. B. connected to two load ports A and B of the valve block 110, which may be connected to a consumer (not shown), such as a hydraulic cylinder.

The 2-way flow control valve 130 has a biasing element F, for example a spring, an input-side supply connection 132, an output-side output connection 134, a first control connection 136, which is connected to a first tap of the 2-way flow control valve 130 which is connected to the 2-way flow control valve 130. Flow control valve 130 is arranged on the output side, is connected, and a second control terminal 138, which is connected to a LS-pressure line 114. The first control port 136 is connected to the first tap of the 2-way flow control valve 130, so that a tapped by the first tap pressure signal via the first control port 136 acts on the 2-way flow control valve 130 such that the pressure signal from one of the biasing element F counteracts generated bias. On the other hand, a pressure signal applied to the 2-way flow control valve 130 through the LS line 114 via the second pressure port 138 assists the bias voltage generated by the biasing element F.

In the in Fig. 2a illustrated illustrative embodiment, the 2-way flow control valve 130 further comprises a second tap arranged on the input side, by means of which a pressure signal in the supply line before the 2-way flow control valve 130 tapped with the pressure signal in the in Fig. 2a shown valve state via a nozzle D1, or alternatively a diaphragm, the first control port 136 is supplied. In this case, the nozzle D1 is connected to the first tap and / or the first control connection 136 over at least a portion of the control stroke of the two-way flow control valve.

According to the in Fig. 2a In the illustrated embodiment, therefore, the 2-way flow control valve 130 is biased in the open control direction by the biasing element F and a pressure medium applied to the second control port 138, while pressure signals supplied to the first control port 136 via the first and second taps are in the on-control direction Act. The first tap is connected to the first control port 136 via a second nozzle D2 regardless of the valve position of the 2-way flow control valve. Is the 2-way flow control valve 130 in the in Fig. 2a shown switching position, a pressure signal p _{P is} tapped at the input side supply terminal 132. Depending on the nozzles D1 and D2, a vaccination of the 2-way flow control valve 130 can now be effected by the pressure signal p _P such that the pressure signal applied to the first control port 136 is determined by the pressure signal p _P , as described below Fig. 3a will be described in more detail.

In general, an open-control direction refers to a control direction of the 2-way flow control valve along which the 2-way flow control valve is opened. In contrast, a control direction to be understood is a control direction of the 2-way flow control valve, along which the 2-way flow control valve is closed.

Assuming that cross-sectional areas of control pistons (not shown) in the two-way flow control valve 130 at the first control port 136 and the second control port 138 are the same (the cross-sectional areas are hereinafter referred to as A _K ), applies in the equilibrium of forces for the 2- Directional flow control valve 130: (p _P - P _LS ) = F _F / A _K , where the pressure p _LS denotes a pressure signal reported by the LS line 114 and the pressure signal p _P is dependent on the pressure signals reported by the first and second taps is formed by the parameters of the nozzles D1, D2 (the spring force is denoted by F _F ; in general, the spring force is a spring preload F _FV and, given the spring constant c _spring , the force resulting from a stroke Δx of the spring F _Hook = c _spring ^* Δx together: F _F = F _FV + F _Hook ). If the load pressure now drops after the proportional directional spool 112, the volume flow through the 2-way flow control valve 130 also decreases. This means that the pressure difference (p _P -p _LS ) also decreases and consequently the pressure p _LS increases slightly or the pressure p _P decreases somewhat. The 2-way flow control valve 130 thus provides a pressure-controlled pressure compensator in which a falsifying pressure signal is applied by the second tap at least over a partial section of the stroke in Zu-control direction or to the first control terminal 136.

In the above consideration (as well as in the corresponding place in the description too Fig. 3a below), a flow force F _flow acting on the control piston does not enter due to the pressure difference occurring at the control piston and the volume flow. The flow force F _flow increases linearly with increasing volume flow up to a maximum value and decreases from the maximum value hyperbolic, so that the flow force F _flow under certain circumstances make up a significant proportion of the equilibrium of forces and would then no longer be negligible without tolerable errors. Taking into account F _flow , the balance of forces follows: (p _P - p _LS ) + F _flow / A _K = F _F / A _K.

In the illustrated valve state, a control of the 2-way flow control valve without the second tap, by a falsifying pressure signal in addition to the tapped from the first tap pressure signal in Zu-control direction acts on the 2-way flow control valve 130, in Auf-control direction such take place that more volume flow would be allowed to pass and the pressure difference balances in the equilibrium of forces to a constant value. Due to the falsifying pressure signal, which acts on the 2-way flow control valve 130 in the Zu-control direction by the second tap, however, a control of the control piston in Zu-control direction, since the falsifying pressure signal, which is tapped by the second tap, in the case a pressure reduction due to a decreasing volume flow or a pressure increase in the load circuit, which is signaled by the LS line 114, which counteracts the LS pressure signal. Accordingly, the control piston is deflected along the Zu-control direction and the volume flow decreases with respect to the case without falsifying pressure signal, so in particular is not regulated to a constant value.

The resulting characteristic for the 2-way flow control valve 130 off Fig. 2a , in which the difference (pump pressure - p _LS ) is plotted against the volume flow, is in Fig. 2b shown schematically, wherein the vertical characteristic curve of conventional 2-way flow control valves (see. Fig. 1b ) is indicated as a dashed line. As can be seen, the characteristic of the 2-way flow control valve 130 is according to the in Fig. 2a illustrated illustrative embodiment with respect to the vertical course of conventional characteristics inclined to the left.

In Fig. 2c FIG. 12 schematically illustrates a flow passage sectional area of the flow control valve along a control stroke according to an embodiment of the present invention. In particular, the course of the flow cross-sectional area at the control edge through the 2-way flow control valve 130 (see curve 1) and at the nozzle D1 (see curve 2) along a stroke H1 of the control piston is shown schematically. According to the illustrated embodiment, the profile of the flow cross-sectional area of the nozzle D1 over a portion of the stroke H1 is constant and then goes to zero.

Fig. 3a schematically shows a valve assembly according to further illustrative embodiments of the invention. The valve assembly includes a valve block 210 and a port block 220 connected to the valve block 210. The connection block 220 has a pilot pressure regulating valve 222 and can be connected to a constant pump system (not shown; Fig. 1a ) or alternatively connected to a control pump system (not shown).

As shown in Fig. 3a Valve block 210 includes a proportional directional spool 212 and a two-way flow control valve 230 disposed in the supply line ahead of proportional directional spool 212. Proportional displacement spool 112 is connected, for example, to two load ports A and B of valve block 210 connected to a consumer (not shown), such as a hydraulic cylinder may be connected.

The 2-way flow control valve 230 has a biasing element F, an input side arranged first supply port 232, an output side arranged output port 234, a first control port 236, with a first tap of the 2-way flow control valve 230, the 2-way flow control valve 230 is arranged on the output side, and a second control terminal 238, which is connected to a LS-pressure line 214. The first control port 236 is connected to the first tap of the 2-way flow control valve 230 so that a pressure signal tapped by the first tap acts on the 2-way flow control valve 230 via the first control port 236 such that the one indicated by the first tap Pressure signal one of the biasing element F, eg a spring, counteracts generated bias. On the other hand, a pressure signal applied to the 2-way flow control valve 230 through the LS line 214 via the second pressure port 238 supports the bias voltage generated by the biasing element F.

In the in Fig. 3a illustrated illustrative embodiment, the 2-way flow control valve 230 further comprises a second tap arranged on the input side, by means of which a pressure signal in the supply line is tapped before the 2-way flow control valve 230, wherein the pressure signal in the in Fig. 3a illustrated valve state via a nozzle D3, or alternatively a diaphragm, the second control terminal 238 is supplied. In this case, the nozzle D3 is connected to the first tap and / or the second control connection 238 over at least a portion of the control stroke of the 2-way flow control valve.

According to the in Fig. 3a In the illustrated embodiment, therefore, the 2-way flow control valve 230 is biased in the open-control direction by the biasing element F and a pressure medium applied to the second control port 238, while pressure signals reported to the first control port 236 from the first tap are in the on-control direction.

Similar to the in Fig. 2a The embodiment shown for the 2-way flow control valve 230, assuming that cross-sectional areas of the control piston (not shown) in the two-way flow control valve 130 at the first control port 136 and the second control port 138 are the same (to be referred to below with A _K For the equilibrium of forces: (p _B -p _A ) = F _F / A _K , where the pressure p _A denotes the pressure which, when the 2-way flow control valve 230 is actively in-between, is connected in series with the nozzle D 3 switched nozzle D4 acts and is reported by the second tap to the second control terminal 238 as a falsifying pressure signal. The pressure p _B represents the pressure signal reported by the first taps (F _F denotes the spring force, as with respect to FIG Fig. 2a above). Furthermore, a load pressure signal p _{LS is} picked off at the point M1 or M2, depending on the switching position of the proportional directional spool 212. When inoculation of the 2-way flow control valve 230 is active, p _LS acts between the load ports and the nozzle D4, otherwise to the control port 238 in the case of inactive vaccination. As will be explained below, the ratio between p _LS and p _{A is given} by the nozzles D3 and D4.

If the load pressure now drops after the proportional directional spool 212, the volume flow through the 2-way flow control valve 230 decreases. With decreasing load pressure the pressure difference (p _B - p _A ) decreases, ie the pressure p _A increases slightly or the pressure p _B decreases slightly. By additionally acting in Auf-control direction falsifying pressure signal p _A is the balance of power compared to in Fig. 1a shown known pressure balance shifted in the open-control direction, so that the 2-way flow control valve 230 is opened further and thus more volume flow through the 2-way flow control valve 230 passes. The 2-way flow control valve 230 thus represents a pressure-controlled pressure compensator, wherein a falsifying pressure signal is applied by the second tap at least over a portion of the stroke in up-control direction or to the second control port 238, in particular, the flow is not constant Value regulated.

With regard to an adjustment of the pressure signal p _A , this can be adjusted according to exemplary embodiments by the nozzle D3 and the nozzle D4 connected in series therewith. In general, in the case of series-connected nozzles or a nozzle chain (the volume flow is constant with nozzles connected in series), the result is at least approximately that for a ratio of from a pressure upstream of the first nozzle (here D3; p _D3 ) in the series to a pressure between the first and second nozzles (here D4, the pressure in front of nozzle D4 is denoted by p _D4 ): p _D3 / p _D4 = (d _D4 / d _D3 ) ⁴ + 1, where d _D4 / d _D3 denotes the diameter of the nozzle D3 / D4. At this point, it should be noted that corresponding to the nozzles D1 and D2 in Fig. 2a above applies.

In the illustrated valve state, a control of the 2-way flow control valve 230 without the second tap, by a falsifying pressure signal acts in addition to the tapped from the first tap pressure signal in Zu-control direction to the 2-way flow control valve 230 in the open-control direction be done in such a way that (compared to the in Fig. 3a illustrated embodiment) would pass less volume flow and the pressure difference in the equilibrium of forces to a (comparatively) lower constant value. Due to the falsifying pressure signal, which acts on the 2-way flow control valve 230 through the second tap, however, in the open-control direction, a control of the control piston takes place in up-control direction, since the falsifying pressure signal, which is tapped by the second tap, in the case a pressure reduction due to a decreasing volume flow or a pressure increase in the load circuit, which is reported by the LS line 114, the LS pressure signal amplified. Accordingly, the control piston is further deflected along the open-control direction and the volume flow continues to increase in relation to the case without falsifying pressure signal.

The resulting characteristic for the 2-way flow control valve 230 off Fig. 3a , in which the difference (pump pressure - p _LS ) is plotted against the volume flow, is in Fig. 3b shown schematically, wherein the vertical characteristic curve of conventional 2-way flow control valves (see. Fig. 1b ) is indicated as a dashed line. As can be seen, the characteristic of the 2-way flow control valve 230 is according to the in Fig. 3a illustrated illustrative embodiment with respect to the vertical course of conventional characteristics inclined to the right.

In Fig. 3c FIG. 12 schematically illustrates a flow passage sectional area of the flow control valve along a control stroke according to an embodiment of the present invention. In particular, the course of the flow cross-sectional area at the control edge is along the two-way flow control valve 230 (see curve 3) and at the nozzle D3 (see curve 4) Hubs H2 of the control piston shown schematically. According to the illustrated embodiment, the passage cross-sectional area of the nozzle D3 is constant over a portion of the stroke H2 and then approaches zero.

By regarding the FIGS. 3a to 3c described example embodiments can be, for example, make a transition from a sub-supply state of the 2-way flow control valve 230 to a sufficient supply state of the 2-way flow control valve 230 without sudden pressure shock, since due to the falsifying pressure signal, a proportional equalization between one at 2-way -Stromregelventil 230 occurring pressure difference and a flowing through the valve volume flow results. In contrast occurs in valves with a vertical curve at the transition to a sudden pressure shock.

Fig. 4a shows a valve assembly according to further illustrative embodiments of the invention. Here, a valve arrangement is shown schematically, which comprises a valve block 310 and a connection block 320 which is connected to the valve block 310. The connection block 320 has a pilot pressure regulating valve 322 and can be connected to a constant pump system (not shown; Fig. 1a ) or alternatively connected to a control pump system (not shown). Valve block 310 further includes a proportional directional spool 312 and a 2/3-way flow control valve 330 disposed in the supply line ahead of proportional directional spool 312. Proportional displacement spool 312 is connected, for example, to two load ports A and B of valve block 310 connected to a consumer (not shown), such as a hydraulic cylinder.

The 2/3-way flow control valve 330 has, according to the in Fig. 4a 1, a biasing element F, an input side arranged first supply port 332, an output side arranged output port 334, a first control port 336, with a first tap of the 2/3-way flow control valve 330, the output side of the 2/3-way flow control valve 330 is connected, and a second control terminal 338, which is connected to a LS-pressure line 314. The first control port 336 is connected to the first tap of the 2/3-way flow control valve 330, so that a tapped by the first tap pressure signal via the first control port 336 acts on the 2/3-way flow control valve 330, that of counteracts the first tap reported pressure signal generated by a biasing element F, such as a spring bias. A through the LS line 314 via the second pressure port 338th on the other hand, the pressure signal applied to the 2/3-way flow control valve 330 supports the bias voltage generated by the biasing element F.

This in Fig. 4a shown 2/3-way flow control valve 330 further has an output side arranged second tap, so that an output side tapped falsifying pressure signal is supplied to the second control terminal 338 via a nozzle D5. According to alternative embodiments of in Fig. 4a the valve arrangement shown, the second tap may be provided on the input side, to supply the second control terminal 338 a falsifying pressure signal tapped on the input side via the nozzle D5. The pressure reported via the nozzle D5 can be adjusted, for example, via a nozzle chain with a nozzle D6, as described above. Due to the second tap, the second control terminal 338 is supplied with an adulterated pressure signal in addition to the LS pressure signal reported at the second control terminal 338, which is applied to the 2/3-way flow control valve via the second tap to support the bias in the open control direction. This is true in a Fig. 4a illustrated valve state a.

In a valve state b, which corresponds to a deflection of the 2/3-way flow control valve 330 from the valve state a in the Zu control direction out, a connection between the second tap and the second control port 338 is separated, while a passage (or an opening cross-section , not shown) between the input side and the output side of the 2/3-way flow control valve is maintained.

In a valve state c, which corresponds to a further deflection of the 2/3-way flow control valve 330 from the valve state b in the Zu-control direction out, the valve is closed in both the passage direction and in a connection between the second tap and the second control terminal 338 , According to some illustrative examples, the 2/3-way flow control valve in valve state c may be fully deflected in the on-control direction.

According to the illustrated embodiment, the adulterated pressure signal picked up at the second tap is reported to the second control port 338 only over a portion of the control stroke in the open control direction. Consequently, a "seeding" of the 2/3-way flow control valve 330 takes place only over a portion of the control stroke. It is thus achieved a better utilization of the corner power in the range of small pressure differences or small volume flows and in Fig. 4a illustrated 2/3-way flow control valve 330 reaches a relatively lower pressure difference at the same amount compared to conventional 2-way flow control valves. Furthermore, a volume flow control in the range of low pressure differences can be made more accurate.

Fig. 4b schematically shows the course of a characteristic of the in Fig. 4a 2/3-way flow control valve 330 shown, wherein a characteristic curve of conventional 2-way flow control valves (see, for example, 130 in Fig. 1a ) is indicated for comparison with a dashed line. It is off Fig. 4b It can be seen that in the 2/3-way flow control valve 330 as shown in FIG Fig. 4a a faster entry into the regular curve section (see RK in Fig. 1b ), in particular, the 2/3-way flow control valve 330 is located according to the in Fig. 4a illustrated embodiment compared to conventional 2-way flow control valves even at smaller pressure differences in the Ausregelbereich, as in Fig. 4b indicated by the mark d.

Fig. 4c schematically shows a profile of the flow cross-sectional area between control edges in the 2/3-way flow control valve Fig. 4a along a control stroke H3 of the 2/3-way flow control valve 330 (see. Fig. 4a ). The in Fig. 4c Curve 5, therefore, shows the flow cross-sectional area between the inlet-side and the outlet-side connections, whereas the curve indicated by curve 6 represents the profile of the flow cross-sectional area of the nozzle D5 along the control piston stroke H3. It can be seen that the nozzle D5 is opened only over a partial section of the control stroke, in particular along a partial section T1, which is smaller than a partial section T2, along which the 2/3-way flow control valve 330 (see FIG. Fig. 4a ) is opened in the forward direction. According to exemplary embodiments, T1 <T2 ≦ H3.

In the embodiments described above with reference to the figures of a proportional directional spool and a consumer is mentioned. This is not a limitation of the present invention. Instead of a consumer and a proportional directional shifter can be in analogy to the representation in Fig. 1a two proportional directional control valve and two consumers or even more than two proportional directional control valve and more than two consumers be provided, wherein before at least one proportional directional spool a pressure compensator with vaccinated characteristic can be provided.

Claims (12)

1. Pressure-controlled 2-way flow control valve (130; 230; 330) for hydraulic applications, wherein a first pressure signal in the closing control direction of the 2-way flow control valve (130; 230; 330) is applicable to the 2-way flow control valve (130; 230; 330) via a first tapping on the output side and a second pressure signal in the opening control direction is applicable to the 2-way flow control valve (130; 230; 330) via an LS pressure signal line (114; 214; 314), and wherein a pressure signal falsifying the first or second pressure signal is applied to the 2-way flow control valve (130; 230; 330) in the closing or opening control direction via a second tapping effective over at least a part of the control stroke of the 2-way flow control valve (130; 230; 330),
   characterised in that
   the falsifying pressure signal is applied only over a part of the control stroke (H1; H2; H3) of the 2-way flow control valve (130; 230; 330).
2. Pressure-controlled 2-way flow control valve (130; 230; 330) according to claim 1, wherein the falsifying pressure signal is applied to the 2-way flow control valve (130; 230; 330) in the part of the control stroke (H1; H2; H3) tapping off the falsifying pressure signal via a first nozzle (D1; D3; D5) or a first orifice in the closed or opening control direction.
3. Pressure-controlled 2-way flow control valve (130; 230; 330) according to claim 2 further comprising a second nozzle (D2; D4; D6) or a second orifice connected in series with the first nozzle (D1; D3; D5) or the first orifice, wherein the falsifying pressure signal is applied to the 2-way flow control valve via a control port (136, 236, 336) disposed between the nozzles (D1, D2; D3, D4; D5, D6) or orifices.
4. Pressure-controlled 2-way flow control valve (130; 230) according to any one of claims 1 to 3, wherein the second tapping is disposed on the input side of the 2-way flow control valve (130; 230).
5. Pressure-controlled 2-way flow control valve (230) according to claim 4, wherein the falsifying pressure signal is applied in the opening control direction so that, as difference between the first pressure signal and the second pressure signal increases, an increasing volume flow is regulated on the output side of the 2-way flow control valve (230).
6. Pressure-controlled 2-way flow control valve (330) according to any one of claims 1 to 3, wherein the second tapping is arranged on the output side of the 2-way flow control valve (330) and the falsifying pressure signal is applied in the opening control direction.
7. Pressure-controlled 2-way flow control valve (330) according to claim 6, wherein the control stroke (H3) has a passage section and a blocking section in which no volume flow occurs at the output side of the 2-way flow control valve (330), wherein the falsifying pressure signal is applied to the 2-way flow control valve (330) in the passage section via a part (T1) of the control stroke (H3).
8. Pressure-controlled 2-way flow control valve (130) according to claim 4, wherein the falsifying pressure signal is applied in the closing control direction so that, as the difference between the first pressure signal and the second pressure signal increases, a decreasing volume flow is regulated on the output side of the 2-way flow control valve (130).
9. Pressure-controlled 2-way flow control valve (130; 230; 330) according to any one of claims 1 to 8, wherein the 2-way flow control valve is configured such that the falsifying pressure signal is blocked over a portion of the control stroke.
10. Valve arrangement for hydraulic applications with a proportional directional spool valve (112; 212; 312) for controlling a hydraulic consumer and with a 2-way flow control valve (130; 230; 330) according to any one of claims 1 to 9, wherein the 2-way flow control valve (130; 230; 330) is connected on the output side to the proportional directional spool valve (112; 212; 312).
11. Valve arrangement for hydraulic applications with a proportional directional spool valve (112; 212; 312) for controlling a hydraulic consumer and with a 2-way flow control valve (130; 230; 330) according to any one of claims 1 to 9, wherein the 2-way flow control valve (130; 230; 330) is connected on the input side to the proportional directional spool valve (112; 212; 312).
12. Valve arrangement according to claim 10 or 11, wherein the proportional directional spool valve (112; 212; 312) together with the 2-way flow control valve (130; 230; 330) is integrated into a valve block (110; 210; 310).

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