DE19603899A1 - Hydraulic control device for supplying pressure medium to several hydraulic consumers - Google Patents

Abstract

The invention concerns a hydraulic control device which has a first pressure medium source (11) and a first priority valve (14) allocated to it, via which the following pressure medium from the first pressure medium source (11) is supplied to a higher-priority hydraulic consumer (19) and to a first lower-priority hydraulic consumer (51). In addition, the hydraulic control device in question has a second pressure medium source (27) and a second priority valve (28) allocated to it, via which pressure medium is also supplied to the higher-priority hydraulic consumer (19) and to a second lower-priority hydraulic consumer (53). According to the invention, the higher-priority hydraulic consumer (19) is supplied respectively with pressure medium from both pressure medium sources (11, 27). To that end, downstream of the primary outlet (15) of the first priority valve (14) is provided a first metering orifice (28) via which a constant pressure difference can be adjusted by the first priority valve (14), and downstream of the primary outlet (15) of the second priority valve (28) is provided a second metering orifice (30) via which a constant pressure difference can be adjusted by the second priority valve (28). The two pressure medium flows flowing through the metering orifices (25, 30) are reunited downstream of the metering orifices.

Description

The invention is based on a hydraulic control device device with which several hydraulic consumers with pressure medium are supplied and the characteristics from the generic term of the An has claim 1.

Such a hydraulic control device is from the DE 41 08 915 A1 known. In this control device is one a first hydraulic pump serving as the first pressure medium source Assigned priority valve, via its primary output from the Hydraulic pump pressure medium flowing to the priority valve priority hydraulic consumer and via its secondary pressure medium flowing in from this hydraulic pump most subordinate hydraulic consumers can be supplied. One a second priority pump is assigned a second priority valve, with its secondary output, a second subordinate hydraulic sher consumers is connectable. About the primary exit of the second priority valve can be the same priority consumer be supplied with pressure medium, which is also from the first Hydro pump is primarily supplied.

In DE 41 08 915 A1 the hydraulic control device is like this designed that with their proper function the priority hydraulic consumer pressure fluid only from the first Hydro pump flows. This must therefore be very large. A pressure medium supply of the priority hydraulic Ver second hydraulic pump is only for an emergency provided in which the pumped by the first hydraulic pump Pressure medium quantity not for operating the priority hydrauli sufficient consumer and the difference between the Pressure at the primary outlet of the first priority valve and the Primary hydraulic consumer load pressure below one certain value drops. Only when the pressure difference is below of this value, the second priority valve is activated.  

The big first hydraulic pump means a big investment in the manufacture of a mobile work device for which a hy Draulic control device of the type outlined primarily is used. In addition, the first hydraulic pump in all cases len in which either the subordinated to be supplied by it Consumer or the primary consumer little or no Need pressure medium, oversized, so that they are then with poor efficiency works.

The aim of the invention is a hydraulic control device with the features from the preamble of claim 1 so on develop that one to be operated primarily with pressure medium hydraulic consumers each the desired pressure medium inflows ge, even if the two hydraulic pumps mainly in With regard to the maximum pressure medium requirement of the subordinate hydraulic consumers are dimensioned and the maxima le Hydraulic fluid requirement of the primary hydraulic consumer above the maximum delivery rate of each of the two hydro pump lies.

This goal is achieved according to the invention with a hydraulic control device achieved the features from the preamble of Claim 1 has and additionally with the features from characteristic part of this claim is equipped. The he Finding is initially based on the knowledge that with mobile Ar beitsgeräte in very many cases the pressure medium requirement of subordinate hydraulic consumer is very low if the priority hydraulic consumer is operated. The priority ge hydraulic consumers can, for. B. egg to the equipment hydraulic excavator or one attached to the excavator Equipment to be attached hydraulic shears. With the later hydraulic consumers, i.e. the various cylinders the equipment of the excavator, the hydraulic motor of the The slewing gear or the traction drive are then usually only correction movements for which the pressure medium requirement is low. In a hydraulic control device according to the invention who the two hydraulic pumps to supply the pressure medium to the  priority hydraulic consumer, so that the maximum pressure medium available to this consumer amount of the sum of the maximum delivery rates of both hydraulic pumps corresponds. Neither of the two hydraulic pumps must therefore be on the summed maximum pressure medium requirement of the assigned subordinate hydraulic consumer and the priority hy draulic consumer. Neither of the two hydro pumping is therefore for the normally occurring operation conditions far oversized.

Advantageous configurations of a hydraulic system according to the invention The control device can be found in the subclaims.

So are preferred according to claim 2, the first orifice and adjust the second orifice coupled together bar. So there is no adjustment of only the first orifice plate only the second orifice plate possible. Rather, every Ver position of an orifice also necessarily an adjustment the second orifice in the same sense.

A directional valve for directional control of the priority hydrauli The consumer is preferably between the first orifice plate and the second orifice plate on the one hand and the priority hydraulic consumer on the other hand arranged. There is only a single orifice-side for the directional control valve Entrance necessary if, according to claim 4, the two over the first Orifice plate and flow paths leading over the second orifice plate merged between these orifices and the directional valve are.

Advantageously, the directional control valve and the metering orifices by a common control signal, e.g. B. can be adjusted by a control pressure that is both at a Effective area of a movable valve member of the directional valve as also on an active surface of a movable element of the measuring balls which is given. Assuming Wegeven is at rest tils and a condition of the orifice plates in which these are closed are first on the directional valve and then on the measuring balls  which opened a flow cross-section. That way is one Fine control of the primary hydraulic consumer of egg nem flow cross-section zero at the orifice plates up to Zero flow cross-section possible at the orifice plates.

Another priority hydraulic user to use with a low pressure medium requirement is expediently in the way described in claim 6 supplied with pressure medium.

Two embodiments of a hydraulic according to the invention Control devices are shown in the drawings. Based these drawings, the invention will now be explained in more detail.

Show it

Fig. 1 shows the first embodiment in which the first pressure medium source are formed by a first constant pump and the second pressure medium source by a second constant pump, and

Fig. 2 shows the second embodiment with two load-sensing controlled variable pumps as pressure medium sources.

In the hydraulic control devices shown, an input P1 of a valve block 10 is connected to the pressure connection of a first hydraulic pump 11 , which sucks pressure medium from a tank 12 . At the input P1 of the valve block 10 is the input 13 of a first priority valve 14 , which is constructed in accordance with generally known ter type and has a primary output 15 and a secondary output 16 . A not shown rule piston 17 of the priority valve 14 is in the sense of an enlargement tion of the flow cross section between the inlet 13 and the primary outlet 15 from the pressure at this primary outlet 15 and in the sense of an increase in the flow cross section between the inlet 13 and the secondary outlet 16 from a compression spring 18 and acted upon by a load pressure of a hydraulic consumer 19 or 20 to be provided primarily with pressure medium. The priority valve 14 maintains a constant pressure difference between the load pressure and the pressure at the primary outlet, which corresponds to the force of the compression spring 18 and which occurs via an intermediate orifice arranged between the priority valve 14 and the hydraulic consumer 19 or 20 . In particular, a first orifice 25 is arranged between the primary output 15 of the priority valve 14 and a pressure line 26 through which pressure medium can flow to the priority hydraulic consumer 19 , which has a large, over the maximum flow rate of the hydraulic pump 11 going beyond maximum pressure medium.

A second input P2 of the valve block 10 is connected to the pressure output of a second hydraulic pump 27 , which also sucks pressure medium from the tank 12 . At the input P2 of the valve block 10 is the input 13 of a second priority valve 28 , which is constructed in the same way as the priority valve 14 and accordingly has a primary output 15 , a secondary output 16 , a control piston 17 and a compression spring 18 .

The control piston 17 of the second priority valve 28 is in the Sin ne an increase in the opening cross section between the input 13 and the primary output 15 from the pressure at the primary output 15 and in the sense of an increase in the opening cross section between the input 13 and the secondary output 16 of the Druckfe of the 18th and the pressure prevailing in the pressure line 26 is impacted. The compression springs 18 of the two priority valves 14 and 28 are the same within the tolerances shown in the exemplary embodiment shown. The priority valve 28 can each flow so much pressure medium from its inlet 13 to its primary outlet 15 that a pressure builds up there, which is a pressure difference corresponding to the force of the associated compression spring 18 above the pressure in the pressure line 26 . The pressure drop takes place via a second orifice 30 , which is arranged between the primary output 15 of the priority valve 28 and the pressure line 26 .

The two orifices 25 and 30 are combined to form a flow valve 31 which, under the action of a compression spring 32, assumes a rest position in which the flow paths are blocked via the orifice plates, and which is hydraulically continuously adjustable from the rest position. The two orifices 25 and 30 are therefore always forced to be adjusted together.

The pressure in the pressure line 26 can be applied to the control piston 17 of the priority valve 14 via a shuttle valve 33 .

Provided that the two orifices 25 and 30 each have the same opening cross-section within certain tolerances and the two compression springs 18 are in turn the same strength within certain tolerances, then the same amount of pressure medium flows through both orifices 25 and 30 apart from tolerance-related deviations Pressure line 26 when the pressure in the pressure line 26 acts not only on the priority valve 28 but also on the priority valve 14 . However, it is also conceivable to make the opening cross sections of the measuring diaphragms 25 and 30 or the compression springs 18 different in size or strength. The contributions of the two hydraulic pumps 11 and 27 to the pressure medium supply of the priority hydraulic consumer 19 are then different.

The pressure line 26 leads into a plate 34 and there via a load holding valve 35 to a pump control chamber P of a 4/3-way valve 40 with which the direction of movement of the double-acting hydraulic consumer 19 can be predetermined. In the middle rest position of the directional control valve 40 , in which this is centered by two adjustable pressure springs 41 , the pump control chamber P is connected via a tank control chamber T to a tank line 42 which leads through the plate 34 and also into the block 10 stretches into it. The directional control valve 40 is hydraulically adjustable with the help of control presses from its central position into a working position in which the consumer control room A or the consumer control room B is connected to the pressure control room P and the respective other consumer control room is connected to the tank control room T. Depending on the desired direction of movement of the hydraulic consumer 19 , a control pressure is given to a control input a or a control input b of the plate 34 . Via a shuttle valve 43 , this control pressure also strikes the current valve 31 . The compression springs of the directional control valve 41 and the compression spring 32 of the flow control valve 31 are designed or preloaded in such a way that movement of the valve member in the flow control valve 31 only takes place when the directional control valve 40 is already switched in a working position. This takes place at a relatively low control pressure in control inputs a or b. A further increase in the control pressure no longer influences the directional control valve 40 , but only the flow cross sections of the measuring orifices 25 and 30 .

In another embodiment, the movements of the valve pistons of the valves 40 and 31 can also take place in parallel. In this way, the return oil flow coming from the consumer 19 can be controlled by control edges in the directional control valve in order, for. B. to produce a slow lowering movement. On the inlet side, the flow cross section in the directional valve 40 should in any case be larger than the added flow cross section at the measuring orifices 25 and 30 in order to avoid energy losses.

The hydraulic consumer 19 which is to be used as a priority is preferably an add-on device such as, for example, an attachment to the equipment of a bagger instead of a spoon. B. egg NEN hydraulic hammer or hydraulic scissors. With the further hydraulic consumer 20 auxiliary movements on the hammer or scissors, for. B. rotary movements who who for which there is only a low pressure medium requirement and which usually take place even when the hydraulic consumer 19 has no pressure medium requirement. The hydraulic consumer 20 is therefore supplied with pressure medium solely via the primary output 15 of the first priority valve 14 . For this purpose, a constant measuring orifice 46 is inserted into a line leading from the primary output 15 of the priority valve 14 to a further 4/3-way valve 45 . The directional control valve 45 is centered by spring force in a central position and is electromagnetically adjustable into a first or a second working position. In the middle position of the directional control valve 45 , the line in which the measuring aperture 46 is located is blocked. The two consumer outputs of the directional control valve 45 are relieved to the tank line 42 . In each de consumer line, which leads from the directional valve 45 to the hydraulic consumer 20 , a hydraulically unlockable return check valve 47 is inserted. The unlocking of a Rückschlagven valve 47 of the one consumer line takes place in each case via the pressure in the other consumer line. Between the directional control valve 45 and the check valves 47 , the highest pressure prevailing in each of the two consumer lines is tapped via a shuttle valve 48 , the output of which is connected to an input of the shuttle valve 33 . The shuttle valves 33 and 48 therefore select the highest of the pressures prevailing in the pressure line 26 and in the consumer connections of the directional control valve 45 and apply it to an active surface on the control piston 17 of the priority valve 14 . In the middle position of a directional control valve 40 or 45 , no load pressure of the corresponding hydraulic consumer 19 or 20 is reported, since the pressure line 26 or the sections of the consumer lines between the check valve 47 and the directional control valve 45 to the tank line 42 are relieved.

Via the secondary output 16 of the priority valve 14 , a hydraulic subsystem 50 is supplied with pressure medium, which has one or more subordinate hydraulic consumers 51 and assigned valves. Separately from the subsystem 50 , a hydraulic subsystem 52 is supplied with pressure medium via the secondary output 16 of the priority valve 28 and has one or more subordinate hydraulic consumers 53 and assigned valves.

In the positions of the flow valve 31 and the directional control valve 40 and the directional control valve 45 shown in FIG. 1, the priority consumers 19 and 20 have no pressure medium requirement. The Re gelkolben the priority valves 14 and 28 are acted upon by the spring pressure from the tank pressure. At the primary output 15 of the priority valves, a pressure corresponding to the compression springs 18 is built up, from which the priority valves are adjusted from the position shown in FIG. 1 to the other position, in which their input 13 is connected to the secondary output 16 . The total amount of pressure medium delivered by the hydraulic pumps 11 and 27 thus flows to the hydraulic subsystems 50 and 52 . If the directional valve 40 and with it the flow valve 31 are now actuated, the load pressure of the hydraulic consumer 19 present in the pressure line 26 is given on the spring side to active surfaces of the control piston 17 of the priority valves 14 and 28 . The priority valves 14 and 28 now regulate by reducing the flow cross-section between their input 13 and their secondary output 16 and by increasing the opening cross-section between their input 13 and their primary output 15 at the latter a pressure which is above the force of the respective spring 18 Load pressure of the hydraulic consumer 19 is. About the orifice plates 25 and 30 there is thus a constant pressure difference, so that the priority hydraulic consumer 19 inflowing pressure medium amount can be adjusted as desired by changing the flow cross section on the orifice plates 25 and 30 .

If only the directional control valve 45 is actuated, the load pressure of the hydraulic consumer 20 is reported on the spring side to the priority valve 14 . In turn, the control piston 17 of the priority valve seeks its equilibrium of forces and provides the opening cross-sections between the input 13 and the outputs 15 and 16 of the valve so that the primary output 15 is present an opposing the force of the compression spring 18 on the reported load pressure pressure. About the orifice 46 there is always the same pressure drop, so that the hydraulic consumer 20 flows a constant amount of pressure medium.

If, as an exception, both directional control valves 40 and 45 are actuated, the highest load pressure occurring at consumer 19 or at consumer 20 is reported to priority valve 14 . If the load pressure of the consumer 19 is higher than the load pressure of the consumer 20 , the pressure drop across the measuring orifice 46 is greater than when the directional control valve 45 is actuated and the hydraulic consumer 20 flows with more pressure medium. Conversely, if the load pressure of the hydraulic consumer 20 is higher than that of the hydraulic consumer 19 , the pressure drop across the measuring orifice 25 will be greater than the force of the compression spring 18 of the priority valve 14 , and the hydraulic consumer 19 will be supplied with more pressure medium than at one isolated actuation of the directional valve 40 .

In the hydraulic control device according to FIG. 1, the two hydraulic pumps 11 and 27 are constant pumps. The subsystems 50 and 52 contain generally known 6-way control valves which have a circulation channel through which pressure medium flowing from the hydraulic pumps into the subsystems can flow to the tank. The hydraulic control device according to FIG. 2 differs from the hydraulic control device according to FIG. 1 only in that the subsystems 50 and 52 with the subordinate hy draulic consumers contain load-sensing control valves and the first hydraulic pump 11 and the second hydraulic pump 27 variable displacement pumps controlled by load sensing. The load-sensing controller 60 of a hydraulic pump is therefore supplied with the highest load pressure of the hydraulic consumer to be supplied with pressure medium by the corresponding hydraulic pump. For this purpose, a shuttle valve 61 is used for the hydraulic pump 11 , which compares the highest load pressure of the hydraulic subsystem 50 with the load pressure acting on the spring side on the priority valve 14 and reports the higher load pressure to the load-sensing controller 60 . For the hydraulic pump 27 , a shuttle valve 61 compares the highest load pressure of the subsystem 52 with the load pressure of the priority hydraulic consumer 19 acting on the spring side of the priority valve 28 and reports the respectively higher pressure to the load-sensing controller 60 of the hydraulic pump 27 .

It is also possible that the one hydraulic pump is a variable displacement pump and the other hydraulic pump is a constant pump.

Claims (6)

1. Hydraulic control device for Druckmittelversor supply several hydraulic consumers ( 19 , 20 , 51 , 53 ) with egg ner first pressure medium source ( 11 ; 27 ) and one of these assigned, first priority valve ( 14 ; 28 ), via its primary output ( 15 ) Pressure medium flowing in from the first pressure medium source ( 11 ; 27 ) can be fed to a primary hydraulic consumer ( 19 ) and pressure medium flowing in from the first pressure medium source ( 11 ; 27 ) can be fed to a first subordinate hydraulic consumer ( 51 ; 53 ) via its secondary outlet ( 16 ), and with a second pressure medium source ( 27 ; 11 ) and one of these assigned, second priority valve ( 28 ; 14 ), via whose primary outlet ( 15 ) from the second pressure medium source ( 27 ; 11 ), the pressure medium also flows to the priority hydraulic consumer ( 19 ) and via its secondary outlet ( 16 ) from the second pressure medium source ( 27 ; 11 ) inflowing pressure medium between a subordinate hydraulic consumers ( 53 ; 51 ) can be supplied, characterized in that the primary output ( 15 ) of the first priority valve ( 14 ; 28 ) has a first measuring orifice ( 25 ; 30 ) via which a constant pressure difference can be adjusted by the first priority valve ( 14 ; 28 ), and that Primary output ( 15 ) of the second priority valve ( 28 ; 14 ) has a second measuring orifice ( 30 ; 25 ), via which a constant pressure difference can be regulated by the second priority valve ( 28 ; 14 ), is arranged downstream, and that the two are connected via the measuring orifices ( 25 , 30 ) flowing pressure medium flows downstream of the orifice plates ( 25 , 30 ) can be brought together. 2. Hydraulic control device according to claim 1, characterized in that the first orifice plate ( 25 ; 30 ) and the second orifice plate ( 30 ; 25 ) are positively coupled together adjustable ver. 3. Hydraulic control device according to claim 1 or 2, characterized in that between the first orifice ( 25 ; 30 ) and the second orifice ( 30 ; 25 ) on the one hand and the prior hydraulic user ( 19 ) on the other hand a directional valve ( 40 ) arranged is. 4. Hydraulic control device according to claim 3, characterized in that the two via the first orifice ( 25 ; 30 ) and the second orifice ( 30 ; 25 ) leading flow paths between these orifices ( 25 , 30 ) and the directional control valve ( 40 ) are brought together. 5. Hydraulic control device according to claim 3 or 4, characterized in that the directional control valve ( 40 ) and the Meßblen ( 25 , 30 ) are adjustable by a common control signal, first on the directional control valve ( 40 ) and then on the Meßblen the ( 25th , 30 ) a flow path is opened. 6. Hydraulic control device according to a preceding claim, characterized in that for Druckmittelversor supply a second priority hydraulic consumer ( 20 ) with a low pressure medium to the primary output ( 15 ) of a priority valve ( 14 ), a third measuring orifice ( 46 ) is closed , The priority valve ( 14 ) at its primary outlet ( 15 ) being able to set a pressure which is one control pressure difference above the higher of the two load pressures of the two priority consumers ( 19 , 20 ).