EP2222964A1

EP2222964A1 - Hydraulic control arrangement and distribution valve section

Info

Publication number: EP2222964A1
Application number: EP08851657A
Authority: EP
Inventors: Peter BÜTTNER; Martin Birk; Armin Stellwagen
Original assignee: Robert Bosch GmbH
Current assignee: Robert Bosch GmbH
Priority date: 2007-11-19
Filing date: 2008-11-14
Publication date: 2010-09-01
Also published as: US20100300086A1; DE102007055377A1; WO2009065383A1

Abstract

A hydraulic control arrangement for pressure medium supply of hydraulic users is disclosed, comprising an LS pump (6), which can be controlled by a pump regulator (8) depending on the highest load pressure in the user. The pressure medium volumetric flow to each user is adjusted using a metering aperture (28), wherein on controlling a user a higher pressure than the load pressure is signalled to the LS pump controller such that the LS pump is controlled according to the higher pressure rather than the low load pressure for said user.

Description

description

Hydraulic control arrangement and directional valve section

The invention relates to a hydraulic control arrangement for pressure medium supply of hydraulic consumers according to the preamble of claim 1 and a directional control valve section for such a control arrangement.

Such hydraulic control arrangements are used for example in mobile hydraulics. Thus, for example, in the forestry of an all-terrain equipment worn machine units are used, the partial work of the harvest, such as cases, entastening, debarking, collecting, drop off can perform. So-called harvesters (harvesters) are used to separate the wood from the hive, to strain, to cut and to collect the timbers cut to length. A harvester head mounted on a crane of the implement has grippers, feed rollers, and a saw for felling, moving, delimbing, and cutting the timbers. All these units are hydraulically actuated, wherein the control is usually done via a mobile control block of the implement.

Frequently, such a control arrangement is designed as a LS system, wherein a demand-controlled variable displacement pump is adjusted in response to the highest load pressure of the simultaneously operated hydraulic consumers by a LS-pump control valve such that the pump pressure is always a predetermined Δp above the highest load pressure of the consumer. The pressure medium volume flow to the individual consumers of the harvester head is set in each case via a directional valve section of the mobile control block, said directional valve section usually having an adjustable metering orifice - formed by a proportionally adjustable directional control valve - and an LS or LUDV pressure compensator.

The harvester head of a forest machine is a product equipped with many functions, in which the equipment components required for the many functions are accommodated in a small space and therefore should be as small as possible. Also necessary for the control of hydraulic consumers on a harvester head hydraulic valves, which are usually housed directly on the harvester head, should take up as little space. If you want to make a cut with a chainsaw, for example, to cut down felled tree trunks, so the saw is to bring to maximum speed before entering the wood, and then drive with the highest possible chain speed as quickly as possible through the trunk. Especially with harvesters

Slightly sawn timber is sawed through relatively quickly, the time required for the saw to go up to high speed, noticeably in the time required for a cut.

In given due to the space available for accommodating valve size, you can increase the flow by the pressure difference across a metering orifice can be greater than usual, for example, by influencing an individual pressure compensator associated with the directional control valve. Of course, the variable displacement pump must be adjusted or set from the outset so that it also delivers the pressure medium quantity causing the greater pressure difference.

A large amount of pressure medium, that is, a high speed or speed of the hydraulic load, for example, the chainsaw at the harvester head, and high dynamics, that is, a quick swinging the variable is obtained - especially in hydraulic consumers whose load pressure of their speed or speed depends - when the reporting line to the pump control valve is connected to the supply line to the directional control valve, so a relation to the load pressure increased pressure, in particular also the pump pressure itself is reported to the pump control valve.

Such an arbitrary increase in the pressure reported to the LS pump control valve can be effected, for example, by means of a control arrangement described in DE 199 30 618 A1 or DE 37 13 824 A1. In these known solutions, a separate valve is provided to increase the reported to the LS pump controller pressure, via which the usual way the load pressure leading, connected to the LS pump regulator LS line is acted upon by the pump pressure, so that the pump when actuated the separate valve is at maximum pressure and thus a hydraulic consumer can be operated with high dynamics. That is, in these known solutions, the corresponding consumer is then driven by a constant pressure system. A disadvantage of this known solution is that a considerable device-technical effort is required because an external valve is required to connect the pump pressure to the LS pump regulator.

In contrast, the invention has the object, a hydraulic

To provide control arrangement and a directional control valve section via which a hydraulic consumer with high dynamics can be controlled.

This object is achieved by a hydraulic control arrangement with the features of claim 1 or a directional control valve section having the features of the independent claim 13.

According to the invention, the hydraulic control arrangement for supplying pressure medium to hydraulic consumers has a demand-regulated variable-displacement pump, the setting of which can be changed by an LS pump control valve as a function of a signaling pressure present in a signaling line. The control arrangement has a directional control valve with a valve slide, via which a metering orifice is controllable, which is arranged in the pressure medium flow path between a feed line fed by the pump and a load line leading to the consumer. The reporting line can be acted upon by connecting to the supply line with a relative to the load pressure of the consumer increased reporting pressure. According to the invention, this takes place in that the signaling line can be connected by adjusting the valve slide with the supply line. The inventive, suitable for such a hydraulic control arrangement directional control valve section is designed accordingly.

In this solution, a higher pressure than the actual load pressure to the LS pump controller is reported when controlling the consumer and the associated adjustment of the associated metering orifice, so that the pump is adjusted accordingly and the pump pressure compared to a solution in which only the current Load pressure to the LS pump controller is reported increases sharply and thus the consumer can be driven with high dynamics. The hydraulic control assembly then operates when driving the consumer under certain circumstances as a constant pressure system with an artificially raised, reported to the LS pump regulator pressure. When the other consumers are activated, the hydraulic control arrangement operates in a conventional manner as an LS system, in which case the LS variable displacement pump is actuated as a function of the highest load pressure of these other consumers. Another advantage of the solution according to the invention is that no external valve is required for switching on the pump pressure, since this connection is integrated into the metering orifice associated with the corresponding consumer.

According to the invention, it is preferred if the metering orifices are each formed by a directional control valve of a directional control valve section of a mobile control block, each section having an LS connection, which can be connected to the pump regulator via the signaling line. In the directional valve section assigned to the constant-pressure consumer, this LS connection can be connected to the supply line via a signaling channel.

According to the invention, it is preferred if at least the directional control valve of the constant pressure consumer is associated with an individual pressure balance. This is preferably designed as a LS-pressure compensator, which is acted upon in the opening direction by the pressure in the LS line and the force of a spring and in the closing direction of the pressure upstream of the metering orifice. This LS-pressure compensator is particularly advantageous when the detection line is opened only after a predetermined opening cross-section of the metering orifice, so that the consumer is initially supplied to a LS control with pressure medium, via the LS-pressure compensator of the pressure medium flow through the metering orifice constant load pressure independent is held and the LS variable displacement pump is controlled in response to the load pressure of this consumer. As soon as the metering orifice has reached the predetermined opening cross section, the message line is opened and, accordingly, an increased pressure is applied to the input of the LS pump regulator, so that the pump pressure rises accordingly.

In a variant of the invention, the LS pressure compensator is designed with a load holding position, in which, when the pump is supersaturated, the pressure medium volume flow can not flow out of the directional control valve section associated with the consumer.

To limit the pump pressure, a conventional LS pressure relief valve used in LS systems can be used, which is provided in the LS line.

The control arrangement according to the invention can be made particularly compact when the signaling channel is integrated in a valve spool of the directional control valve. This integration of the signaling channel in the valve spool, for example, take place in that it branches off from a connecting channel which connects a downstream of the metering orifice located portion of a consumer channel with the reporting line. The signaling channel branches off between two nozzles, with a signaling nozzle being arranged in the signaling channel itself. By the latter and the downstream of the metering orifice located a flow divider is formed, at which the higher reporting pressure is tapped.

In an alternative solution, a longitudinal bore of the valve slide is formed in the fluid path to the detection line, in which a radial bore opens, via which a pressure medium connection to the supply line is made after a predetermined stroke of the valve spool.

In this case, a second radial bore of the valve slide can be provided, whose opening cross section is smaller than that of the first radial bore.

The hydraulic control arrangement according to the invention and the method according to the invention can be used particularly advantageously in mobile hydraulics, for example in a harvester head.

The LS-way valve section according to the invention is designed in accordance with the preceding embodiment.

Other advantageous developments of the invention are the subject of further subclaims.

In the following, a preferred embodiment of the invention is explained in more detail with reference to schematic drawings. Show it:

1 shows a circuit diagram of a first embodiment according to the invention of a hydraulic LS control arrangement for supplying pressure medium to a consumer, wherein a pressure divider consisting of two small nozzles in the bypass to the metering orifice serves to report an increased pressure;

Figure 1 a is the circuit diagram of a variant of the directional control valve of Figure 1, wherein the pressure is tapped immediately upstream of the metering orifice for the message; Figure 2 shows an embodiment of a hydraulic control arrangement with a LS-way valve section with an individual pressure compensator without load.

FIG. 3 shows an exemplary embodiment of a hydraulic control arrangement with an LS directional control valve section, which has an individual pressure compensator designed with a load-holding function;

Figure 4 shows another embodiment of a hydraulic control arrangement with a LS-way valve section, wherein at a small stroke of the control piston of the directional valve, the load pressure and a larger stroke, an increased pressure in the reporting line is given.

Figure 5 shows a concrete solution of the directional control valve section according to Figure 4 and

FIG. 5a shows a variant of the solution according to FIG. 5.

In mobile work equipment, such as a used in forestry vehicle with a crane head held on a crane, the pressure medium supply of individual hydraulic consumers, such as grippers, feed rollers, saws or hydraulic cylinders for adjusting the crane via preferably several LS-Mobilsteuerblöcke, the one Have a plurality of directional valve sections, which are each assigned to one of the aforementioned consumers. FIG. 1 shows a circuit diagram of a hydraulic control arrangement with such a directional valve section for controlling a hydraulic consumer, for example a hydraulic drive of a saw of a harvester head.

According to the hydraulic control arrangement shown in Figure 1, the drive, in the present case a hydraulic motor 1, via a dot-dash line directional control valve section 2 of a mobile control block with a LS variable displacement pump 6 and connected to a tank T. The LS variable displacement pump 6 may be designed, for example, as an axial piston pump whose pivoting angle is adjustable via an LS pump regulator 8. The pressure connection of the variable displacement pump 6 is connected via an inlet line 10 to an input port P of a directional control valve 24 of the directional control valve section 2. The directional control valve 24 further has a tank connection T, which is connected via a drain line 12 to the tank T. Two working connections A, B of the directional control valve 24 are connected via a feed line 14 and a return line 16 to the inlet connection or the outlet connection of the hydraulic motor 1. The Directional control valve 24 further has an LS connection, which is connected via a load-reporting line 18 and a shuttle valve cascade of which only one shuttle valve 20 is shown in Figure 1, with an LS line 22 is connected. About the shuttle valve cascade of the highest load pressure of all controlled via the mobile control block consumers is tapped and reported in the LS line 22. The pressure in the LS line 22 is applied to the LS pump regulator 8, wherein this adjusts the pivot angle of the LS variable displacement pump 6 such that a by a predetermined Ap, for example, 20 bar, lying above the pressure in the LS line Pump pressure is set.

The continuously adjustable directional control valve 24 is biased by a centering spring assembly 26 in a basic position (0), in which the ports P, A and B are locked. The load-reporting line 18 is connected to the drain line 12 in this basic position (0). Via pilot valves, not shown, or via proportional solenoids, a valve slide of the directional valve 24 can be displaced in the direction of its (a) marked positions.

In these adjusting positions, the cross-section of a metering orifice 28 between the input port P and the working port A and a flow cross-section between the working port B and the tank port P is controlled, so that pressure medium via the flow line 14 to the hydraulic motor 1 and from its low-pressure side via the return line 16 and the directional control valve 24 can flow to the tank T. Furthermore, in these positions (a), the connection to a load-signaling room 30, which is merely indicated in FIG. 1, is shut off and a load-signaling room 32 is connected to the load-signaling line 18. As will be explained in the following, an LS pressure limiting valve for limiting the maximum pressure reported to the LS pump regulator 8 can be provided in the load message room 32.

As shown in FIG. 1, upstream of the metering orifice 28, in the directional control valve 24, a signaling channel 34 branches off with a comparatively small cross-section forming a message nozzle 36. This signaling channel 34 terminates in a built-in valve spool of the directional control valve 24 connecting channel 38 in the region between two nozzle sections 40, 42. The connecting channel 38 connects a downstream of the metering orifice 28 located portion of the directional control valve 24 with the load reporting line 18. Through this reporting channel 34 and with The nozzle cross-section 42 provided part of the connecting channel 38, a bypass is formed, in which the two nozzles 30, 42 form a pressure divider, on which via the nozzle cross section 40 of the increased signal pressure is tapped. Through the nozzles 36, 40 and 42, which, as is apparent from Figure 5, holes of small diameter in the control piston, it is ensured that flow through the channels away from the metering orifice only small amounts of pressure medium. Suffice a small pressure relief valve to limit the pressure in the channel 18. The losses are low when the pressure limiting function.

For operation of the hydraulic motor 1, when this drives the chainsaw on a harvester head, the directional control valve in the direction of the (a) marked positions usually deflected maximum. At least in this position, the nozzles 36 and 42 are open to port P and port A of the directional control valve. Parallel to the metering orifice 28, a small quantity of pressure medium flows through the nozzles 36 and 42 from P to A. Between the two nozzles, a pressure between the pressure in P and the pressure in A is established, which flows via the nozzle 40 into the load-signaling channel 18 and is reported to the pump controller 8. This in turn adjusts the pump 6 so that the pressure in P is above the reported pressure by the pump Δp. This means that the pressure drop across the nozzle 36 is equal to the pump Δp. The amount of pressure medium flowing in the bypass to the metering orifice is obtained from the flow cross-section of the nozzle 36 and the pressure drop via this nozzle, that is to say the pump Δp. This amount of pressure medium also flows through the nozzle 42 and generates at this a pressure drop, which depends on the flow cross-section. By choosing the flow cross-section of the nozzle 42 in comparison to the flow cross-section of the nozzle 36 can thus determine how much higher the reported pressure is above the pressure in A. For example, if the flow area of the nozzle 42 is the same as the flow area of the nozzle 36, then the reported pressure is the pump Δp above the pressure in A. The variable displacement pump is then multiplied to root (normal flow rate without nozzle 36) 2) to produce a pressure drop across the metering orifice 28 that is twice the pump Δp. The variable displacement pump is due to the relative to the load pressure in port A of the directional valve increased reported pressure quickly adjusted to a high flow, possibly to maximum flow, if this maximum flow provided by the pump Δp and the flow cross sections of the nozzles 36 and 42 pressure drop over the Metering orifice 28 not yet created. Below the maximum flow rate would remain the pump, if the pressure regulator, with which a LS-variable displacement pump for maximum pressure protection is usually also equipped, or a to the

Load signaling lines 18 or 22 connected pressure relief valve would respond. In the variant of the directional control valve 24 according to FIG. 1a, the nozzle 42 from FIG. 1 is missing as a limiting case of the variant according to FIG. 1. Here, precisely the pressure in connection P of the directional control valve, ie the pump pressure via the nozzles 36 and 40, is reported in the load-signaling channel 18. unless a pressure relief valve is connected to the channel 18 or 22, which responds. If such a pressure relief valve does not exist, the two nozzles are not necessary. In the case of the presence of a pressure relief valve is sufficient to one of the two nozzles. As far as both exist, they add up in their effect. Even if they are not currently necessary, they are drawn in as long as they represent flow cross-sectional constrictions compared to the other LS fluid path sections in the structural design.

Missing as in the variant of Figure 1a, the bypass to the orifice 28, the pump swings particularly fast to maximum flow, as the pump pressure is reported to the LS pump control valve, unless previously the pressure cutoff of the pump control intervenes or on to a LS-line connected pressure relief valve responds.

When the directional control valve 24 is adjusted to the positions indicated by (b), the position lying between the inlet connection P and the working connection B becomes

Opened metering orifice 28 and opened the pressure medium connection from the working port A to the tank T, so that the hydraulic motor 1 can be driven in the reverse direction of rotation. In these positions, the actual load pressure downstream of the metering orifice 28 is tapped and reported via the Lastmeldeleitung 18, the shuttle valve 20 and the LS line 22 to the LS pump controller 8, so that the adjustment of the pump takes place in dependence on the actual load pressure. In principle, however, the pump pressure can be reported to the pump controller 8 even when adjusting the directional control valve 24 in direction (b) via a channel corresponding to the signaling channel 34, so that the pressure medium supply of the hydraulic motor 1 also takes place as a function of the pump pressure.

The control arrangement shown in FIG. 1 is preferably used when very large quantities of pressure medium are to flow via the directional valve section 2.

FIG. 2 shows a variant of the control arrangement according to FIG. 1, the basic structure being essentially identical, so that only the differences from FIG. 1 are explained and, moreover, the same for corresponding components Reference numerals are used and reference is made to the relevant description of Figure 1.

In the control arrangement shown in Figure 2, the directional control valve section 2 is designed with a LS-pressure compensator 44 which is arranged in the pressure medium flow path between the LS variable displacement pump 6 and the directional control valve 24 in the supply line 10. The LS- pressure compensator 44 is acted upon in the closing direction via a control line 45 from a pressure upstream of the metering orifice 28 and downstream of the opening cross section of the LS-pressure compensator 44 and in the opening direction by the force of a spring 46 and the pressure in the load-sensing line 18.

Upon adjustment to the positions indicated by (a), the pressure prevailing between the nozzles 36 and 42 via the nozzle 40 and the load-sensing line 18 is correspondingly applied to the control surface of the pressure compensator regulating piston which acts in the opening direction. The pressure upstream of the metering orifice 28 is higher than the pressure acting on the opening side of the pressure compensator 44 in accordance with the force of the spring 46, so that here too a large pressure drop across the metering orifice 28 is possible.

FIG. 3 shows a variant of a control arrangement which differs from the exemplary embodiment according to FIG. 2 only in that the LS pressure compensator 44 is designed with a load-holding function. Their pressure balance piston is in turn acted upon by the spring 46 and the pressure in the load-sensing line 18 in the opening direction and in the closing direction, if not in load, by the pressure in the pressure medium flow path downstream of the opening cross section of the LS pressure compensator 44 and upstream of the LS directional control valve 24. This pressure is tapped within the LS-pressure compensator 44 via a pressure compensator piston bore 47 and applied to the right in Figure 3 control surface of the pressure compensator piston. When not controlled LS variable displacement pump 6 or in the case in which it has not yet built up a pressure necessary to hold a load after opening the directional control valve, the LS pressure compensator 44 by the force of the spring 46 and the pressure in the Lastmeldeleitung 18th held in its illustrated load-holding position or brought there, so that the pressure medium can not flow from the inlet side of the hydraulic motor 1 via the controlled directional control valve 24. Incidentally, the embodiment shown in Figure 3 corresponds to that of Figure 2, so that further explanations are unnecessary.

The control arrangements according to FIGS. 2 and 3 are preferably used, if not always the maximum pressure medium volume flow for actuation is required by the consumer, but at least in certain Hubbereichen the directional control valve load-independent control of the hydraulic consumer should be possible. You can now choose the position of the signaling channel 34 so that it is initially closed and is turned on only after a predetermined stroke of the directional valve spool. During this partial stroke then the LS-way valve section 2 operates in a conventional manner according to a LS control with a small pressure difference across the metering orifice 28, wherein first the load pressure at the controlled consumer in the spring chamber of the LS-pressure compensator 44 is reported. Upon further movement of the valve spool, the higher pressure is then reported to the LS pump controller

The circuit diagram of such an embodiment of a control arrangement with so-called booster function is shown in FIG. The only difference from the exemplary embodiment according to FIG. 3 is that during the adjustment in the direction (a) of the directional control valve (24), the signaling channel 34 is initially not opened in intermediate positions (c). The metering orifice 28 is opened in these intermediate positions with a comparatively small cross section. The pressure corresponding to the load pressure downstream of the metering orifice 28 is tapped via the two nozzle cross sections 42, 40. Accordingly acts on the LS port of the directional control valve 24 and the load reporting line 18 first, the load pressure in the opening direction on the LS pressure compensator 44, so that the pressure drop across the metering orifice 28 corresponds to the force of the spring 46 and thus load pressure is kept constant independent. The variable displacement pump 6 is adjusted in dependence on this load pressure.

In the further adjustment of the directional control valve 24, the positions indicated by (a) are reached, in which in the manner described above, the signaling channel 34 is opened with the reporting nozzle 36, so that the pressure prevailing between the two nozzles 36 and 42 in the Lastmeldeleitung 18 and so that in the spring chamber of the LS-pressure compensator 44 and the LS-pump controller 8 is applied, so that the variable displacement 6 further pivots and a high pressure medium flow to the hydraulic motor 1 is promoted. If the cross section of the nozzle is substantially larger than the cross section of the nozzle 42, practically the pump pressure is reported to the LS pump regulator, so that the pump goes to maximum delivery.

Incidentally, the embodiment shown in Figure 4 corresponds to the above-described embodiment, so that further explanations are unnecessary. Figure 5 shows a concrete embodiment of the directional control valve section 2 of Figure 4. The basic structure of this directional valve section 2 is known from the prior art, for example from the data sheet RD 64 282 of the Applicant, so that only the essential features will be described. The concrete directional valve section 2 is designed in disc design and has a directional control valve 24 with forming valve slide 52 which is biased via the Zentrierfederanordnung 26 in its basic position and by means of, for example, designed as a pressure reducing valves pilot valves 53, 55 in the direction of (a) or (b ) marked positions is adjustable. The directional control valve 24, the LS-pressure compensator 44 is connected upstream, the control piston 54 is shown by the force of the spring 46 in his

Load holding position is biased, in which the pressure medium connection is shut off from a pressure port P to a connecting channel 56 which extends between the input of the directional control valve 24 and the output of the LS-pressure compensator 44. The pressure downstream of the control edge of the LS pressure compensator 44 is tapped via the control piston 54 passing through pressure balance bore 47 and acts on the right in Figure 4 end face of the control piston 54th

In its illustrated basic position, the valve spool 52 of the directional valve 24 shuts off the pressure medium connection between the connecting duct 56 leading the pressure P 'downstream of the LS pressure compensator 44 and the two working ports A, B of the directional control valve section 2. When one of the pilot valves 53, 55 is actuated via control grooves 58 and 60, the pressure medium connection to the hydraulic motor 1 in the manner described above or controlled. The load applied to the working ports A, B load pressure, ie the pressure downstream of the metering orifice 28 controlled by the control edge 58 or 60 (see Figure 4) is tapped via a longitudinal bore 62 and small radial bores 64, 66 of the valve spool 52. The two radial bores 64 and 66 respectively form the nozzle cross-section 42 according to FIG. 4. These small radial bores 64 and 66 open, when the directional valve 24 is adjusted, into the part connected to the connections A, B, depending on the adjustment direction The load pressure then applied in the longitudinal bore 62 is formed via a small radial bore section 72 in which the nozzle cross section 40 of FIG. 4 is formed, and an arc channel forming the load reporting line 18 into the spring chamber of the LS pressure balance 44 reported, so that according to the control piston 54 is acted upon in the opening direction (relative to the control position) with the load pressure. This load pressure is also applied to the pump regulator 8. The maximum load pressure can be limited in the directional control valve section 2 shown by the connected to the load alarm room 32 LS-pressure relief valve 48. In this respect, the structure of the directional valve section 2 completely corresponds to the known solution. This known directional valve section 2 is modified in the embodiment according to the invention so that after a predetermined stroke of the valve spool 52 in the sense of a connection of the channel 68 with the channel 56 at least one more

Radial bore 74 of the valve spool, which opens internally into the longitudinal bore 62, is opened to the channel 56 out. The radial bore 64, which forms the nozzle 42 of Figure 4 in the considered direction of actuation of the valve spool has been previously opened to the channel 68 out. Thus, now the two nozzles 36 and 42 having bypass to the metering orifice 28 which at the control edge 58 of the

Valve spool is formed, opened. The prevailing between the two nozzles, compared to the load pressure increased pressure is reported to the pressure compensator 44 and the pump regulator 8. The radial bore 74 forms the nozzle 36 from FIG. 4.

To increase the cross section of the nozzle 36 may over the circumference of the

Valve spool distributed further lying in the same radial plane radial bores are provided. Ultimately, then the pressure in the longitudinal bore 62 will be almost equal to the pressure in the channel 56.

With a small stroke of the valve spool 52 (positions (c)) thus a sensitive control of the consumer is possible, while further adjustment in the positions (a), the consumer is supplied with a high pressure medium flow. If one does not need the sensitivity, then one can do without the bore 68. With a single small bore 74 can then be the pressure from the channel 56 in the longitudinal bore 62.

The maximum load pressure can be limited in the directional control valve section 2 shown by the connected to the load alarm room 32 LS-pressure relief valve 48.

When adjusted in the direction (b), the radial bore 74 is controlled relative to the channel 56. In a conventional manner, the load pressure at the working connection B is reported via the bore 66 into the spring chamber of the LS pressure compensator 44 and to the pump regulator 8. In principle, however, then a second alarm bore could be effective, so that in the direction (b), the LS variable displacement 6 is adjusted in the sense of increasing the pressure medium flow rate. In the directional control valve of Figure 5, it is important that the longitudinal bore 62 with an adjustment of the valve spool 52 in the sense of connecting the terminal A with the channel 56 with this channel 56 and with an adjustment of the valve spool in the sense of a connection of the terminal B with the channel 56 is connected to the channel 70. This can, as the variant of Figure 5a shows, also by a single radial bore and an axially closed, radial bore open towards the longitudinal groove 80 in the outer surface of the valve spool 52 can be achieved. According to Figure 5a, the radial bore is the standard radial bore 66 through which the pressure in port B is tapped. The longitudinal groove extends from the radial bore 66 between two fine control grooves 60 of the valve slide 52 in the direction of the channel 56 facing the end face.

If now the valve spool 52, as viewed in FIG. 5a, is displaced to the left from its shown middle position, the longitudinal groove 80 opens to the channel 56 after a certain stroke. Thus, the longitudinal bore 62 of the valve spool is connected to the channel 56. In a displacement of the valve spool from its central position in the opposite direction, the longitudinal bore 62 is connected after a shorter stroke with the channel 70 and thus to the terminal B. In the variant according to FIG. 5a, therefore, the idea according to the invention is realized in a very simple way, whereby care must not be taken in a complicated way to ensure that a

Radial bore the fine control grooves 60 cuts. There may be two radial bores 66 and longitudinal grooves 80 distributed over the circumference of the valve spool 52, as shown in FIG. 5a. This is based on symmetry considerations. From the cross-section ago ansich suffice a bore 66 and a longitudinal groove 80, since in the variant of Figure 5a no bore 68 is present. In this respect, this variant corresponds to the circuit diagram of FIG. 1a.

Disclosed are a hydraulic control system and a method for pressure medium supply of hydraulic consumers, with a LS pump, which is controlled via a pump controller in response to the highest load pressure of the consumer. The pressure medium volume flow to each consumer is set via a respective metering orifice, wherein when driving a consumer, a higher pressure than the load pressure to the LS pump controller is reported, so that the LS pump not driven according to the low load pressure of this consumer but according to the higher pressure becomes. LIST OF REFERENCES:

1 hydraulic motor

2-way valve section

6 LS variable pump

8 LS pump controller

10 supply line

12 drain line

14 flow line

16 return line

18 reporting line

20 shuttle valve

22 LS line

24 way valve

26 centering spring arrangement

28 metering orifice

30 load indicator room

32 load signaling room

34 signaling channel

36 message nozzle

38 connecting channel

40 nozzle cross-section

42 nozzle cross-section

44 LS pressure balance

45 control line

46 spring

47 Pressure compensator piston bore

48 LS pressure compensator limiting valve

50 channel

52 valve spool

53 pilot valve

55 pilot valve

54 control piston

56 connection channel

58 tax rate

60 tax rate

62 longitudinal bore

64 radial bore radial bore

channel

Radial bore section

reporting hole

longitudinal groove

Claims

18 / 20Patent claims

1. Hydraulic control arrangement for pressure medium supply of several hydraulic consumers, with a demand-current-controlled (Ioad-sensing-regulated) variable displacement pump (6) whose setting in response to a in a reporting line (18) pending reporting pressure by a LS-pump control valve (8) is variable with a directional control valve (24) which has a valve slide (52) in a valve bore, with which an opening cross-section of a feed line (10) fed into a fluid path between a feed line (10) fed by the pump (6) and a consumer line leading to a load (1) (14) located metering orifice (28) is controllable, wherein the reporting line (18) can be acted upon by connecting to the supply line (10) with respect to the load pressure of a consumer (1) increased reporting pressure, characterized in that the reporting line (18) by adjusting the valve spool (52) of the directional control valve (24) with the supply line (10) is connectable.

2. A hydraulic control arrangement according to claim 1, wherein the consumers (1) associated metering orifices (28) are each formed by a directional control valve (24) of a directional control valve section (2) of a mobile control block, each directional control valve (24) has an LS connection, the is connected via the reporting line (18) with the LS pump control valve (8) and in which the one consumer (1) associated directional control valve (24) via a reporting channel (34) with the supply line (10) is connectable.

3. Hydraulic control arrangement according to claim 1 or 2, wherein at least the directional control valve (24) of the one consumer (1) is associated with an individual pressure compensator (44).

4. Hydraulic control arrangement according to claim 3, wherein the individual pressure compensator is a LS pressure compensator (44) and the reporting line (18) between the pressure compensator (44) and the metering orifice (28) with the supply line (10) is connectable.

5. Hydraulic control arrangement according to one of the claims 2 to 4, wherein the signaling channel (34) only at a certain opening of the metering orifice (28) is aufsteuerbar and in the intermediate region of the LS-connection with a downstream of the metering orifice (28) is located area. 19/20

6. Hydraulic control arrangement according to one of the claims 3 to 5, wherein the individual pressure compensator (44) is designed with a load holding position in which the pressure medium connection between the consumer (1) and LS variable displacement pump (6) is locked.

7. Hydraulic control arrangement according to one of the preceding

Claims, with a LS pressure relief valve (48) for limiting the voltage applied to the LS pump regulator (8).

8. Hydraulic control arrangement according to one of the claims 2 to 7, wherein the signaling channel (34) substantially in a valve spool (52) of the directional control valve (24) is integrated.

9. A hydraulic control arrangement according to claim 8, wherein in the fluid path to the signaling line (18) has a longitudinal bore (62) of the valve slide (52) and wherein the valve spool (52) has at least a first inside to the longitudinal bore (62) open radially bore (74) has, after a certain stroke of the valve spool (52) from the central position in the one direction to a in the valve bore, in which the valve spool is located, opening portion (56) of the supply line (10) is opened.

10. A hydraulic control arrangement according to claim 9, wherein in an adjustment of the valve slide (52) in one direction at least a second inside to the longitudinal bore (62) open towards the radial bore (64) of the valve spool to the supplied consumer channel (68) is opened out and the entire flow cross section of the at least one first radial bore (74) is substantially greater than the flow cross section of the second radial bore (64).

11. A hydraulic control arrangement according to claim 8, 9 or 10, wherein the signaling channel (34) branches off from a connecting channel (38) connecting a downstream of the metering orifice (18) located portion of a consumer channel (14) with the reporting line (18) the signaling channel (24) branches off between two nozzles (40, 42) and a signaling nozzle (36) is arranged in the signaling channel (24)

12. A hydraulic control arrangement according to one of the preceding claims, wherein the consumer is an aggregate of a harvester head.

13 LS-way valve section for controlling a consumer (1) with a guided in a valve bore valve slide (52), with an opening cross-section of a 20/20

Zumessbrende (28) is controllable, which is arranged in a fluid path between a with a supply line (10) connected to the pressure port (P) and a consumer with a channel (14) connected to the consumer port (A), and with a reporting line (18) via the one Signaling pressure to an LS connection can be applied, characterized in that the reporting line (18) by adjusting the

Valve spool (52) with a fluid path between the pressure port (P) and the metering orifice (18) is connectable.

14. LS-way valve section according to claim 13, wherein in the fluid path to the signaling line (18) has a longitudinal bore (62) of the valve slide (52) and wherein the valve slide (52) at least a first inside to the longitudinal bore (62) open towards radial bore (74 ) which, after a certain stroke of the valve spool (52), is opened from the central position in one direction to a section (56) of the supply line (10) which opens into the valve bore in which the valve spool is located.

15. LS-way valve section according to claim 14, wherein in an adjustment of the valve slide (52) in one direction at least a second inside to the longitudinal bore (62) open towards the radial bore (64) of the valve spool to the supplied consumer channel (68) is opened and where the total flow area of the at least one first radial bore (74) is substantially greater than the flow area of the second radial bore (64).