EP1812715A2

EP1812715A2 - Hydraulic control arrangement

Info

Publication number: EP1812715A2
Application number: EP05799204A
Authority: EP
Inventors: Gerhard Keuper; Peter Stachnik; Heinrich Lödige; Sönke Jessen
Original assignee: Bosch Rexroth AG
Current assignee: Bosch Rexroth AG
Priority date: 2004-10-06
Filing date: 2005-10-06
Publication date: 2007-08-01
Anticipated expiration: 2025-10-06
Also published as: US20080202110A1; WO2006037318A1; DE102004048684A1; EP1812715B1; US7870728B2

Abstract

The invention discloses a hydraulic control arrangement (1) for controlling a number of consumers (2, 4), particularly of a mobile working machine. In addition to the consumers of the control arrangement, an additional consumer (50) should be able to be connected to a power beyond connection. All consumers and power beyond consumers are supplied with hydraulic fluid by a pump (6). An input pressure scale (52) is provided downstream from the pump, and the greater of the load pressures of the consumers or of the at least one power beyond consumer is present on the control connection of said input pressure scale.

Description

description

A hydraulic control arrangement

The invention relates to a hydraulic control arrangement for controlling a plurality of consumers according to the preamble of patent claim 1 and a control method for such a hydraulic control arrangement.

Such hydraulic control arrangements are used in particular in mobile work equipment, such as wheel loaders or tractors to provide their consumers, such as the working hydraulics, the steering or traction drives and accessories with pressure medium.

From US 5,540,049 a closed-center system is known in which the pressure medium supply via an electrically controlled variable displacement pump. The variable displacement pump is assigned a bypass valve, via which a connection to a tank can be opened. The adjustment of the variable displacement pump, the bypass valve and the closed-center valves connected upstream of the consumer is carried out electrically via control devices, inter alia as a function of the pump pressure and of the path of one of the valve slides of the closed-center valves. In this known solution thus takes place an electronic speed or force control / control of consumers.

From EP 0 462 589 B1, EP 0 432 266 B2 and DE 41 27 342 C2 hydraulic control arrangements are known, which are designed as LS system. In such LS systems, the flow rate of the pump is so regulated that in the pump line to a by a certain pressure difference .DELTA.p above the highest load pressure of the consumer lying pump pressure is applied. In the known systems, each consumer an adjustable metering orifice and an individual pressure compensator are assigned, via which the pressure medium flow to the load can be kept constant independent of the load depending on the setting of the metering orifice. In these LS systems downstream of the pump, an inlet pressure compensator can be provided, via which a connection to the tank can be opened. These input weighers are acted upon in the closing direction by a control pressure corresponding to the highest load pressure. The pressure difference at which the inlet pressure compensator opens is usually slightly larger than the Δp set by the pump.

To connect attachments or attachments without their own pressure medium supply a so-called power beyond connection is provided, which may have a pressure line, a return line and an LS line. This power beyond connection also makes the load sensing system of the implement suitable for the implement. Such solutions are known for example from DE 102 14 850 Al and DE 42 39 109 C1.

The problem with provided with power beyond ports hydraulic control arrangements is that no information about the

Pressure medium volume demand of or connected to the power Beyond connection consumers (power beyond consumers) are present. In the case of an undersupply in the system, depending on the load pressure, uncontrolled behavior of one or more consumers may occur. It is usually not possible to target individual consumers of the system backtrack to operate other, prioritized consumers in a desired manner.

On the other hand, the present invention seeks to provide a control method and a hydraulic control arrangement, in which when connecting at least one power beyond consumer to a power Beyond connection a pressure medium supply of all consumers is improved over the known solutions.

This object is achieved by a hydraulic Steueranordung with the features of claim 1 and a control method according to claim 20.

According to the invention, the hydraulic control arrangement has a pump whose flow rate is adjustable and over which at least one consumer can be supplied with pressure medium. The consumer is connected upstream of a metering orifice, via which the pressure medium volume flow to the consumer is set. The pump is followed by an inlet pressure compensator, via which a connection can be opened to a tank line leading to a tank. The control arrangement further has a power beyond connection to which a power beyond consumer is connected. According to the invention, the control of the inlet pressure compensator in dependence on the largest of those load pressures applied to the consumers of Steueranordung and the power beyond consumers. Ie. , the load pressure of the power beyond consumer is used to adjust the pressure in a pump or supply line determining incoming pressure compensator, so that by their appropriate setting disturbance by the power beyond consumer is almost impossible. Such disorders occur at the beginning of the described Technology especially at low load pressure and high pressure medium volume flow.

According to the control concept according to the invention, the pump and / or the metering orifices of the consumers are controlled in such a way that, when the power beyond consumer is supplied via the inlet pressure compensator, a predetermined residual volume flow to the tank is established in order to avoid undersupply. The pump can be adjusted depending on the setting of the inlet pressure compensator. This can be done for example by measuring the residual volume flow or by position sensing a slider of the inlet pressure compensator.

According to the invention, the pressure medium supply of the power beyond consumers takes place either via the inlet pressure compensator or via power beyond individual pressure compensators.

In the former alternative, the inlet pressure compensator is preferably acted upon by the largest of the load pressures in the closing direction.

The inlet pressure compensator is then designed in a preferred embodiment, that in a spring-biased position the connection to the priority consumer and the tank is shut off and when adjusting the inlet pressure compensator in the opening direction, the connection to the priority consumer and then to the tank is aufsteuerbar. A sufficient supply of the priority consumer is ensured when the said residual volume flow flows to the tank.

In the event that a second or more power beyond consumers are connected, they can either simultaneously or in. a predetermined order of priority on the inlet pressure compensator with. Pressure medium to be supplied. To set a priority then, for example, the second power Beyond consumer be preceded by a power beyond pressure compensator, in the closing direction of the force of a spring and the same control pressure as the inlet pressure compensator and in the opening direction of the at the entrance of the power beyond Pressure compensator applied pressure applied. Ie. , this power beyond pressure compensator opens only when the pressure medium supply of the former Power Beyond consumer is secured.

In the second inventive concept, according to which the power beyond consumers do not have the

Incoming pressure compensator, but can be supplied with pressure medium via Power Beyond pressure compensators, in a variant of the invention, the inlet pressure compensator and the power beyond pressure compensator are acted upon in the closing direction of the largest of the load pressures.

It may be advantageous to connect the input pressure balance of the power beyond pressure compensator, so that then the inlet pressure compensator is connected in parallel to the power beyond consumer to the output of the power beyond pressure compensator.

In an alternative solution variant, the inlet pressure compensator and the power beyond pressure compensator are loaded in the opening direction by the highest of the load pressures.

Other possible solutions are when the inlet pressure compensator in the closing direction is acted upon by the highest of the load pressures and provided between the output of the inlet pressure compensator and the tank, a diaphragm is, wherein the pressure upstream of this aperture in the opening direction acts on the power beyond pressure compensator over which the power or beyond consumers are supplied with pressure medium.

Alternatively, the inlet pressure compensator can also be acted upon in the opening direction by the highest of the load pressures, in which case the pressure downstream of the diaphragm also acts in the opening direction on the power beyond pressure compensator.

The pump can be designed as an electrically controllable variable displacement pump or as a variable speed fixed displacement pump.

According to the invention, it is preferred if the hydraulic control arrangement is embodied as an LS system, wherein each of the metering orifices assigned to a consumer is preceded by an individual pressure compensator.

The springs of the individual pressure compensators assigned to the consumers, the power beyond pressure compensators associated with the power beyond consumers, and the inlet pressure compensator are matched to one another such that either consumers or power beyond consumers are prioritized.

According to the invention, the opening pressure difference of the inlet pressure compensator is set to be greater than the opening pressure differential of the individual pressure compensators and the power beyond pressure compensators, whereby the opening pressure difference across the power beyond pressure compensators may be greater or smaller than that via the individual pressure compensators, depending on prioritization. The adjustment of the metering orifices can be done electrically, hydraulically or mechanically.

The tapping of the highest of the load pressures is preferably carried out via a shuttle valve, at one input of the highest load pressure of the consumer and at the other input of the highest load pressure of the power Beyond consumer is applied, so that tapped at the output of the larger of these load pressures and fed to the inlet pressure compensator can be.

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

In the following preferred embodiments of the invention will be explained in more detail with reference to schematic drawings. Show it:

Figures 1, 2 and 3 embodiments of control arrangements according to the invention, in which power Beyond consumers are supplied via an inlet pressure compensator with pressure medium and

Figures 4 to 8 embodiments in which the pressure medium supply of the or the power beyond consumer takes place via a power beyond pressure compensator.

FIG. 1 shows a hydraulic control arrangement 1 of a mobile working implement, for example a farm tractor. This control arrangement can be formed for example by a mobile control block, via which the hydraulic consumers of the working hydraulics of the working device, in the present case two double-acting cylinders 2, 4 are supplied with pressure medium, which is supplied by a pump 6 and returned by the consumers to a tank T. , The pump 6 is in the illustrated embodiment as electrically controllable variable displacement pump whose pivot angle is adjustable via a pump regulator 8. Instead of an electrically controllable variable displacement pump, a variable speed fixed displacement pump or the like can be used.

The sucked by the pump 6 from the tank T pressure fluid is conveyed into a pump line 10, which branches into two supply lines 12, 14, wherein the supply line 12 to the cylinder 2 and the supply line 14 is assigned to the cylinder 4. Ie. , the pressure medium volume flow Qvw supplied by the pump 6 is branched into partial pressure medium volume flows Qvwi ^{un <} 3-QvW2. The supply lines 12, 14 are each connected to an input port P of a continuously variable directional control valve 16 or 18, through which the pressure medium flow direction to or from the consumer and the pressure medium volume flow can be adjusted. To working ports A, B of the directional control valves 16, 18 supply lines 20 and 22 and return lines 24 and 26 are connected, wherein the flow lines 20, 22 with a bottom-side cylinder chamber 28 and 30 and the return lines 24, 26 with a piston rod side annular space 32 and 34 of the cylinders 2, 4 are connected. With appropriate operation of the directional control valve 16, 18 can of course be referred to as a forward or return line line also act as a return or flow line.

The actuation of the two-way valves 16, 18 via one or more pilot control devices 36, via the control spaces of the directional control valves 16, 18 are acted upon with a control pressure to the valve spool from its illustrated locking position (closed center) in the indicated positions (a) or ( b) to adjust, in which either the cylinder chamber 28, 30 or the annulus 32, 34 is supplied with pressure medium, while the pressure medium is then displaced from the respective other pressure chamber. In this case, a Zulaufmeßblende is controlled via an inlet control edge, whose opening cross-section determines the pressure medium volume flow to the cylinder 2, 4. The pressure medium flowing back from the cylinder 2, 4 is returned to the tank T via a tank connection T and a tank line 38 connected thereto.

In the illustrated embodiment, in each case one load ml or m2 is moved over the two cylinders 2, 4. In FIG. 1, the pressure medium volume flow flowing in via the feed lines 20, 22 is denoted by QAI * QA2 ^and the outflowing pressure medium volume ^{flow is denoted} by Q _Q -J or QQ2. In the lines are then each the indicated pressures PB2 ^on -

Upstream of each directional control valve 16, 18 is in the corresponding flow line 12 and 14, a LS or individual pressure compensator 40, 42 is provided, which is acted upon in the opening direction respectively by the force of a pressure compensator spring 44 and 46 and the load applied to the respective load 2, 4 , In the closing direction, the pressure in the DruckmittelStrömungspfad between the output of the respective individual pressure compensator 40, 42 and the input of the downstream directional control valve 16, 18 acts on the pressure compensator slider 40, 42 and the associated, through the directional control valve 16 , 18 formed metering orifice, a flow regulator is formed over which the pressure drop across the orifice can be kept constant independent of the load. The control arrangement further has an inlet pressure compensator 52, which is arranged in a branch line 54 branching off from the pump line 10. Via the inlet pressure compensator 52, a connection to the tank T can be opened.

Up to here, the control arrangement 1 according to the invention substantially corresponds to the structure as described in the aforementioned prior art.

To connect a device with an additional hydraulic consumer to the mobile implement, such as a loading wagon or a potato harvester, the system is provided with a power beyond connector to which this additional consumer, hereinafter referred to as power beyond consumer 50, can be connected.

In the illustrated embodiment, the inlet pressure compensator 52 is designed as a 3/3-way pressure balance, the slide in the closing direction of the force of a spring 56 and at the output of a

Pressure compensating valve 58 applied pressure and in the closing direction of the pressure in the branch line 54 and thus the pressure in the pump line 10 is acted upon. At the inputs of the pressure compensator exchange valve 58, on the one hand, the highest load pressure of the two consumers 2, 4, which is tapped via a shuttle valve 48 and corresponding LastmeldeIeitungen of the directional control valves 16, 18. At the other input of the pressure compensator changeover valve 58 is the load pressure of the power beyond consumer 50, which is tapped via a power Beyond-Lastmeldeleitung 68. The pressure slide of the inlet pressure compensator 52 is acted upon in the closing direction by the highest of the load pressures which are applied to the consumers 2, 4 and to the power beyond. Consumers 50 are present. The power beyond consumer 50 is connected via an inlet channel 60 to a working port A of the 3/3-way pressure compensator. The pressure medium flowing away from the power beyond consumer 50 is conducted via an outlet channel 64 into the tank line 38. At the tank connection T of the inlet pressure compensator 52, a tank channel 62 leading to the tank T is connected.

The opening pressure difference .DELTA.pgDW ', which must be applied to fully open the inlet pressure compensator 52, is determined by the force of the spring 56. In the illustrated embodiment, the path of the valve spool of the input pressure compensator 52 is detected via a displacement sensor 66 and converted into a signal which is applied to a signal input of the pump controller 8, so that the adjustment of the pump in response to the path of the pressure compensator slide of the inlet pressure compensator 52 takes place.

When the power beyond consumer 50 is not actuated or not connected, the inlet pressure compensator 52 is closed and the working hydraulics of the tractor (cylinders 2, 4) are supplied with pressure medium. Upon actuation of the power beyond consumer 3, the inlet pressure compensator 52 is adjusted in the opening direction, so that it can be supplied with pressure medium. The pump 6 is adjusted in response to the path of the pressure compensator slide of the inlet pressure compensator 52 so that a small residual volume flow flows through the tank port T - (the inlet pressure compensator 52 is then open to the power beyond consumer 50 and the tank T out). This ensures that all consumers 2, 4 and the power beyond consumer 50 are adequately supplied with pressure medium. In the illustrated embodiment, the control of the pump 6 takes place in dependence on the path of the Pressure compensator valve of the inlet pressure compensator 52, alternatively, the residual volume flow flowing out to the tank T could also be detected and used to set the pump 6. In the pump controller 8, the signal corresponding to the actual path of the pressure compensator slide YEDWist ^m ^ is compared to a stored in a data storage setpoint - the adjustment of the pump 6 then takes place in response to this control difference via a control algorithm.

In this embodiment, the opening pressure difference of the input pressure compensator 52 will generally be greater than the opening pressure difference of the individual pressure compensators 40, 42, d. H. , the spring 56 is stronger than the pressure compensator springs 44, 46.

The following described embodiments differ from the above

Embodiment only in the manner in which the inlet pressure compensator 52 is executed and how the or the power beyond consumers are controlled. It can therefore be dispensed with the representation of the consumer 2, 4, the associated directional control valves 16, 18 and the individual pressure compensators 40, 42, these are the same in the following embodiments as in the embodiment described above.

The embodiment shown in Fig. 2 corresponds in principle to the solution shown in Fig. 1, but instead of a single consumer, two power beyond consumers 50, 70 are driven. The inlet pressure compensator 52 is designed as a 4/4-way pressure compensator, wherein the input terminal P of the inlet pressure compensator 52 is connected to the branch line 54, while the pressure medium supply of the two power beyond consumers 50, 70 via the Inlet passage 60 and a further inlet channel 72 takes place, which are connected to two output terminals A, B of the pressure compensator 52. The inlet pressure compensator 52 is again acted upon in the closing direction by the force of the spring 56 and the highest load pressure of the consumers 2, 4 and the two power beyond consumers 50, 70, wherein the greater of the load pressures of the two power beyond consumers 50, 70 is tapped via a power beyond shuttle valve 73. In the opening direction, the inlet pressure compensator 52 in turn is acted upon by the pressure at the inlet port P. The inlet pressure compensator 52 is designed so that when inoperative or disconnected power beyond consumers 50, 70, the inlet pressure compensator 52 is shut off. Upon actuation of both power beyond consumers 50, 70, the power beyond consumer 50 is first supplied with pressure medium and on a further displacement of the pressure compensator slide the connection to the other power beyond consumer 70 aufgesteuert. That is, in this solution shown in FIG. 2, the power beyond consumer 50 is prioritized over the power beyond consumer 70. When the inlet pressure compensator 52 is completely open, a residual volume flow flows via the tank channel 62 to the tank T. The path of the pressure compensator slide is detected as in the above embodiment via the transducer 66 and guided via a signal line 74 to a signal port of the pump controller 8 and processed in the manner described above - the adjustment of the pump 6 is again such that a predetermined residual flow to the tank T. flows out, so that a sufficient supply of all consumers and the power beyond consumers 50, 70 is ensured.

In the dargestellen in Fig. 3 embodiment, the same inlet pressure compensator 52 as in Embodiment of FIG. 1 used, but over which two power beyond consumers 50, 70 can be supplied with pressure medium. For this purpose, the connected to the output terminal A inlet channel 60 branches into two Zulaufzweigkanäle 76, 78, via which the pressure medium to the power beyond consumer 50 or 70 is performed. In the inlet branch channel 78, a power beyond pressure compensator 80 is provided, which is acted upon in the closing direction by the force of a pressure compensator spring 82 and the highest of the occurring load pressures, which is tapped from the output of the pressure compensator shuttle valve 58. In the opening direction of the power beyond pressure compensator 80 is acted upon by the pressure at its input terminal P. The opening pressure of this power beyond pressure compensator 80 is smaller than that of the inlet pressure compensator 52 and the individual pressure compensators 40, 42 chosen. By interaction of the inlet pressure compensator 52 and the power beyond pressure compensator 80 takes place in this

Embodiment, a prioritization of the power beyond consumer 50 against the power beyond consumer 70th

In the three above-described embodiments, the pressure medium supply of the or the power beyond consumers 50, 70 always via the inlet pressure compensator 52, which lies in the pressure fluid flow path between the pump line 10 and the associated load 50, 70. In the embodiments described below, the pressure medium supply to the consumer takes place directly, d. H. , bypassing the inlet pressure compensator 52 via associated power beyond pressure compensators.

Fig. 4 shows a variant of the control arrangement 1, in which the inlet pressure compensator 52 is designed as a 2/2-way pressure compensator, wherein the input terminal P as in the above-described embodiments is connected to the branch line 54 and the tank port T opens via the tank passage 62 into the tank. The inlet pressure compensator 52 is acted upon by the pressure at the inlet port P in the opening direction and by the force of the spring 56 and the highest applied to the output of the pressure compensating valve 58, the load pressures in the closing direction. The path of the pressure compensator valve spool is in turn detected by a displacement sensor 66 and used to control the pump 6.

The pressure medium supply of the power beyond consumer 50 takes place in accordance with FIG. 4 via the power beyond pressure compensator 80, which is acted upon in the opening direction by the pressure in the pump line 10 and in the closing direction by the force of the pressure balance spring 82 and the highest of the load pressures. which is tapped at the output of the pressure compensating valve 58. The power beyond pressure compensator 80 is arranged in a power beyond feed 84 branching off from the pump line 10.

In this variant, the inlet pressure compensator 52 and the power beyond pressure compensator 80 are arranged in parallel and each designed as a 2/2-way pressure compensator. The opening pressure Äp ^ DW d- ^he inlet pressure compensator is greater than that of the power beyond pressure compensator 80th and the two individual pressure compensators 40, 42 (Δpißw ^ 2) 'wherein either the opening pressure of the two individual pressure compensators 40, 42 or that of the power Beyond pressure compensator 80 can be selected to be larger, to set a prioritization. That is, it can first the power beyond consumer 50 or the working hydraulics of the tractor (cylinder 2, 4) are supplied with pressure medium. Also in this embodiment, a supply of all consumers 2, 4, 50 is ensured when the pump 6 is set so that a residual volume flow flows through the inlet pressure compensator 52 to the tank T out.

In Fig. 5 a variant of the embodiment shown in Fig. 4 is shown, wherein the inlet pressure compensator 52 is not - as in Fig. 4 - parallel, but in series with the power beyond pressure compensator 80 is connected. That is, the branch line 54 leading to the input port P of the input pressure compensator 52 does not branch from the pump line 10 but from the inlet port 60 connecting the output port A of the power beyond pressure compensator 80 and the power beyond consumer 50. The input pressure compensator 52 is thus supplied with pressure medium only after the control of the power beyond pressure compensator 80. Both pressure compensators 52, 80 are designed as a 2/2-way pressure compensator and are biased over the highest of the load pressures in the closed position and by the pressure applied in each case at the input P in the open position. Depending on the choice of pressure compensator springs 44, 46, 82 and the spring 56 of the input pressure compensator, either the power beyond consumer 50 or the consumers 2, 4 can be prioritized. The opening pressure difference of the inlet pressure compensator 52 is again greater than the opening pressure difference of the individual pressure compensators 40, 42 and the power beyond pressure compensator 80 selected. Incidentally, the function corresponds to that of the embodiment of FIG. 4th

FIG. 6 shows an exemplary embodiment in which two power beyond consumers 50, 70 are to be supplied with pressure medium. These are each associated with a power beyond pressure compensator 80 or 86, which are each connected via branching off from the pump line 10 power beyond supply lines 84, 88 with the associated power Beyond consumers 50, 70. The two Power Beyond pressure compensators 80, 86 and the inlet pressure compensator 52 are each designed as 2/2-way pressure compensators. The input pressure compensator 52 is biased in this embodiment by the tapped via the pressure compensating valve 58 highest of the load pressures in the opening direction, while in the closing direction, only the spring 56 acts. The output port of the inlet pressure compensator 52 is connected via the tank channel 62 to the tank T. The two power beyond pressure scales 80, 86 are biased only by the force of a pressure compensator spring 82 and 90 in the closing direction, while in the opening direction in this embodiment, the highest of the load pressures acts, which is tapped at the output of the pressure compensator shuttle valve 58.

This embodiment allows a variety of functional sequences, since depending on the spring selection of the individual pressure compensators 40, 42 and the power beyond pressure scales 80, 86, either the working hydraulics of the tractor (consumers 2, 4) and then the power beyond consumers 50, 70 or vice versa, or at first only one of the power beyond consumers, then the working hydraulics and then the other power beyond consumers 70, 50 can be supplied with pressure medium.

Corresponding to the pump control and the pressure medium requirement, a residual volume flow will occur when the inlet pressure compensator 52 is open and the pump 6 is actuated in dependence on this residual volume flow or on the position of the pressure compensator piston of the inlet pressure compensator 52 in order to avoid undersupply.

FIG. 7 shows an exemplary embodiment with the connection of a power beyond consumer 50, in the basic structure corresponds to that of FIG. 4. In this solution too, the power beyond consumer 50 is supplied with pressure medium via a power beyond pressure compensator 80 arranged in the power beyond supply line 84. The inlet pressure compensator 52 is arranged in the branch line 54 and acted upon in the opening direction by the pressure in this branch line 54, while in the closing direction, the force of the spring 56 and the tapped on the pressure compensating valve 58 highest load pressure act. In contrast to the exemplary embodiment according to FIG. 4, a diaphragm 92 is provided in the tank channel 62 connected to the outlet port T of the inlet pressure compensator 52, via which a control pressure is generated at the residual volume flow flowing to the tank T, which is tapped via a control line 94 and to the in Opening direction effective control surface of the power beyond pressure compensator 80 is guided. This is acted upon in the closing direction by the force of the spring 82. In this variant, first the consumers 2, 4 of the working hydraulics are supplied with pressure medium and only after increasing the residual volume flow and corresponding pressure drop in the tank channel 62, the power beyond pressure compensator 80 opened, so that then the power beyond consumer 50 is supplied with pressure medium , As with all embodiments described above, when the residual volume flow to the tank T exceeds a certain size, it is used for pump control.

In the fail-safe case, the residual volume flow through the inlet pressure compensator 52 to avoid undesirable high pressure drops at the aperture 92 via a parallel to the aperture 92 switched bias valve to the tank.

Also in this embodiment, the opening pressure of the individual pressure compensators 40, 42 of Working hydraulics greater than the opening pressure of the Power Beyond pressure compensator 80 set and the opening pressure of the inlet pressure compensator 52 is - as in all embodiments - preferably greater than that of the individual or power beyond pressure scales selected.

Finally, FIG. 8 shows an exemplary embodiment in which the principle explained with reference to FIG. 7 for controlling a plurality of power beyond consumers 50, 70 is used. Each of the two power beyond consumers 50, 70 is associated with a respective power beyond pressure compensator 80, 86, which are arranged in branching off from the pump line 10 power beyond supply lines 84 and 88 and over which the two power Beyond Consumers 50, 70 are supplied with pressure medium. The inlet pressure compensator 52 is formed and interconnected as in the above-described embodiment, wherein the aperture 92 is again provided in the tank channel 62, which generates a control pressure for controlling the two power beyond pressure compensators 80, 86. Also in this embodiment, first the consumers 2, 4 of the working hydraulics of the tractor are supplied with pressure medium, a

Pressure medium supply of the two power beyond consumers 50, 70 takes place only when a sufficient control pressure is built up in front of the aperture 92. However, the two power beyond consumers 50, 70 can be prioritized by a suitable choice of the pressure balance springs 82, 90 with each other.

The concept according to the invention makes it possible to easily connect power beyond consumers and to ensure a desired pressure medium supply of all consumers even under unfavorable operating conditions (for example low load pressure, high pressure medium volume flow). The power beyond connection can be realized with comparatively few components, wherein in the embodiments according to FIGS. 1-8, the pressure compensator types (DW) listed in the following table are used. In this table, DW means: pressure compensator, PB: power beyond consumer and Δp: the respective opening pressure of the pressure compensators, whereby the indices EDW denote the

Input pressure scale, IDW 1, 2 The individual pressure balances of the working hydraulics and IDW 3, 4 characterize the Power Beyond pressure balances.

In the design of the components according to the table, the choice of spring forces or the

Opening pressure differences of the individual pressure compensators with the indices 1 and 2 and possibly 3 and 4 interchangeable, which in individual cases to different prioritization of consumers 2, 4 and the power beyond consumers 50, 70 may result.

In principle, a direct control of a power beyond consumer 50, 70 without its own valve is possible in conjunction with electrical directional control valves 16, 18. In this case, the pressure medium volume flow to the power beyond consumer 50, 70 results from the difference of the set pump volume flow and set at the working ports of the directional control valves 16, 18 pressure medium flow rates in normal operation, ie in accordance with the input pressure compensator 52 correctly adjusted pump. TABLE

Furthermore, especially in one

Low supply with electrically controlled valves a flow management possible. So z. B. prioritization of the power beyond consumers, the other consumers if necessary be taken back so far that the power beyond consumer is always optimally supplied. This can be recognized by the position signal or the residual volume flow via the inlet pressure compensator 52.

The use of the invention is possible with the use of electrically adjustable control pumps and variable speed constant displacement pumps, in particular in conjunction with open center and LS valves, which are operated mechanically, electrically or electro-hydraulically. In principle, the invention is suitable for all working hydraulic applications of mobile hydraulics whose consumers are not fixed from the outset.

Disclosed is a hydraulic control arrangement for controlling a plurality of consumers, in particular a mobile working device, wherein in addition to the consumers of the control arrangement, a power beyond consumer to a power beyond connection should be connected. All consumers and power beyond consumers are supplied by a pump with pressure medium, downstream of the pump, an inlet pressure compensator is provided at the control terminal of which the greater of the load pressures of the consumer or the at least one power beyond consumer is present. LIST OF REFERENCE NUMBERS

1 control arrangement

2 cylinders

4 cylinders

6 pump

8 pump controller

9 control algorithm

10 pump line

12 supply line

14 Inlet line

16 way valve

18 way valve

20 flow line

22 presentation

24 return line

26 return line

28 cylinder space

30 cylinder space

32 annulus

34 annulus

36 pilot control unit

38 tank line

40 individual pressure balance

42 individual pressure balance

44 Pressure compensator spring

46 Pressure compensator spring

48 changes1

50 power beyond consumers

52 inlet pressure scale

54 branch line

56 spring

58 Pressure compensator1venti1

60 inlet channel

62 tank channel Flow channel Position transducer Power beyond load indicator Power beyond load Inlet channel Power beyond valve Signal line Inlet branch channel Inlet branch channel Power beyond pressure scale Pressure balance spring Power beyond supply line Power beyond pressure scale Power beyond supply line Pressure balance spring Aperture control line

Claims

claims

1. Hydraulic control arrangement for controlling a plurality of consumers (2, 4), in particular a mobile working device, which can be supplied via a pump (6) with adjustable flow rate with pressure medium, which is connected downstream of an inlet pressure compensator (52) via which a connection to a tank (T) is aufsteuerbar, each consumer (2, 4) is associated with an adjustable metering orifice (16, 18), and with a power beyond connection, to which at least one power beyond consumer (50, 70) can be connected , characterized in that the setting of the inlet pressure compensator (52) in dependence on the largest of the load pressures of the consumer (2, 4) and the at least one power beyond consumer (50, 70) takes place.

2. Control arrangement according to claim 1, wherein the pump (6) in dependence on the setting of

Input pressure balance (52) can be controlled.

3. Control arrangement according to claim 1 or 2, wherein the power beyond consumer (50, 70) via the inlet pressure compensator (52) can be supplied with pressure medium and the largest of the load pressures the inlet pressure compensator (52) acted upon in the closing direction.

4. Control arrangement according to claim 3, wherein the inlet pressure compensator (52) in a spring-biased

Basic position, the connection to the power beyond consumer (50, 70) and the tank (T) shuts off and opens when adjusting in the opening direction, first the connection to the priority consumer (50, 70) and then to the tank (T).

5. Control arrangement according to claim 4, wherein a second power beyond consumer (70) is connected, which is supplied via the inlet pressure compensator (52) simultaneously with or after the first power beyond consumer (50) with pressure medium.

6. A hydraulic control arrangement according to claim 5, wherein the second power beyond consumer (70) is preceded by a power beyond pressure balance (80) in the closing direction of the force of a spring (82) and the same control pressure as the inlet pressure compensator ( 52) and in the opening direction of the pressure at its input terminal (P) is acted upon.

7. A hydraulic control arrangement according to claim 1 and 2, wherein at least one power beyond consumer (50, 70) in bypassing the inlet pressure compensator (52) via a power beyond pressure compensator (80, 86) can be supplied with pressure medium.

8. Control arrangement according to claim 7, wherein the inlet pressure compensator (52) in the closing direction of the largest of the load pressures and the force of a spring (56) and in the opening direction of the pressure at its input (P) is acted upon.

9. Control arrangement according to claim 8, wherein the power beyond pressure balance in the closing direction of the largest of the load pressures and the force of a spring (82) is acted upon.

10. Control arrangement according to claim 9, wherein the inlet pressure compensator (52) to the power beyond pressure compensator (80) is connected in series.

11. Control arrangement according to claim 7, wherein the inlet pressure compensator (52) is acted upon by the highest of the load pressures in the opening direction.

12. Control arrangement according to claim 11, wherein the at least one power beyond pressure compensator (80, 86) in the opening direction of the highest of the load pressures and in the closing direction of the force of a spring (82, 90) is acted upon.

13. Control arrangement according to claim 8 or 11, wherein downstream of the inlet pressure compensator (52) in a tank (T) leading tank line (62), a diaphragm (92) is arranged and in the opening direction on the at least one power beyond pressure compensator (80 , 86) acting pressure between the diaphragm (92) and the inlet pressure compensator (52) is tapped, wherein the power beyond pressure balance (80, 86) in the closing direction of the force of a spring (82, 90) is acted upon.

14. Control arrangement according to one of the preceding claims, wherein the pump (6) is an electrically controllable variable displacement pump or a variable speed fixed displacement pump.

15. Control arrangement according to one of the preceding claims, wherein each metering orifice (16, 18) an individual pressure compensator (40, 42) is connected upstream, in the opening direction of a pressure compensator spring (44) and the highest load pressure of the consumer (2, 4) and in the closing direction from the pressure at the output of the individual pressure compensator (40, 42) is acted upon.

16. Control arrangement according to claim 15, wherein the pressure compensator springs (44, 46) of the individual pressure compensators (40, 42) and the power beyond pressure compensators (80, 86) and the Input pressure compensator (52) are matched to one another such that either consumers (2, 4) or power beyond consumers (50, 70) are prioritized.

17. Control arrangement according to claim 16, wherein the

Opening pressure difference of the inlet pressure compensator (52) is greater than the opening pressure difference of the individual pressure compensators (40, 42) or the power beyond pressure compensators (80, 86) is selected.

18. Control arrangement according to one of the preceding claims, wherein the metering orifices are formed by electrically, hydraulically or mechanically adjustable directional control valves (16, 18).

19. Control arrangement according to one of the preceding claims, with a pressure compensator change-over valve (58), at the input on the one hand, the largest load pressure of the consumer (2, 4) and on the other hand, the largest load pressure of the or the power beyond consumer (50) is applied and its output is connected to a control chamber of the inlet pressure compensator (52).

20. A control method for a hydraulic control arrangement according to claim 1, characterized in that the

Pump (6) and / or the metering orifices (16, 18) of the consumer (2, 4) are controlled such that when pressure medium supply of the at least one priority consumer (50, 70) via the inlet pressure compensator (52) has a predetermined

Residual volume flow to the tank (T) out results.

21. A control method according to claim 20, wherein the pump (6) is set in dependence on the residual volume flow or the position of a pressure compensator slide of the inlet pressure compensator (52).