Hydraulic pressure medium supply assembly and method for a mobile working machine

Abstract

The present invention discloses a hydraulic pressure medium supply component, which has an adjustable axial piston machine, wherein the regulating cylinder is controlled by a pilot valve. The pilot valve is controlled by a control device. The control device has the actual pressure and / or actual swing angle of the adjustable axial piston machine as input parameters. One or more of the input parameters mentioned are compared with the matching rated values ​​and a regulating value is output or a regulating value is output respectively. The regulation of the input parameters mentioned is part of a first control loop. The lower second control loop has input parameters based on one or more regulating parameters, which are used as rated parameters. Another input parameter of the second control loop is the actual delivery volume regulation speed of the axial piston machine. Then, the regulating value for the pilot valve is set as the output parameter for the second control loop.

Description

Technical Field

[0001] The invention relates to a hydraulic pressure medium supply assembly for an open hydraulic circuit, for example for a mobile working machine. Background Art

[0002] A pressure and delivery flow control system is known from the document RD 30630 / 04.13 of Rexroth. The pressure and delivery flow control system is used to electrohydraulically control the swing angle, pressure and power of an axial piston-adjustable pump. The control system has an axial piston-adjustable pump with an electrically controlled proportional valve. The regulating piston can be controlled by the control system. The regulating piston is used to adjust the swash plate of the adjustable pump. The following displacement sensor is provided for the adjustable piston, through which the swing angle of the swash plate can be determined by means of the displacement of the adjustable piston. As an alternative to the displacement sensor, the swing angle of the swash plate on the swing shaft can also be measured by a Hall sensor. The volume flow of the adjustable pump can be obtained from the swing angle of the swash plate. The adjustable pump is driven by a motor. If the adjustable pump is not driven and the regulating system is pressure-free, the adjustable pump swings to the maximum delivery volume by the spring force of the spring. On the contrary, in the driving state of the adjustable pump and when the pilot valve has no current and the pump outlet is closed, the adjustable pump swings to zero stroke pressure. The balance between the pump pressure on the regulating piston and the spring force of the spring occurs at about 4 to 8 bar. The basic setting is usually adopted in the voltage-free control electronics. The control device for the pilot valve has a rated pressure, a rated swing angle and optionally a rated power value as input variables. The actual pressure on the outlet side of the regulating pump is detected by a pressure sensor. As mentioned above, the actual swing angle is obtained by a displacement sensor. The recorded actual value is digitally processed in the electronic unit and compared with the predetermined rated value. The minimum value generator ensures that only the regulator assigned to the desired working point is automatically activated. The output signal of the minimum value generator is the rated value of the proportional magnet on the pilot valve. In order to control the pilot valve, the displacement displacement of the valve core of the pilot valve is detected by a displacement sensor and notified to the control device. In the document RD 30242 / 03.10 of Rexroth, an external control electronics device for the described regulation of an axial piston-adjusting machine is disclosed. In addition, in the document RD 92 088 / 08.04 of Rexroth, an electrohydraulic control system is disclosed.

[0003] EP 1 460 505 A2 discloses a method for separating pressure and delivery flow. Control. Here, a pivotable hydraulic axial piston control machine is provided, which is connected to another hydraulic machine via a transmission shaft. In addition, a control circuit for the drive torque of the control machine is provided. The actual drive torque and the rated drive torque are fed to the control circuit, from which the control variable for the control device of the control machine is determined. The rated drive torque is in turn the output variable of the minimum value generator. Here, the minimum value generator selects the output variables of the pressure control and the volume flow control. Here, the volume flow of the hydraulic machine connected to the control machine is set as the actual volume flow. In addition, the high pressure of the hydraulic machine is set as the actual pressure.

[0004] In addition, documents EP 2 851 565 B1, US Pat. No. 4,801,247, US Pat. No. 5,182,908, EP 034 9092 B1, US Pat. No. 5,267,441, US Pat. No. 5,967,756 and US Pat. No. 5,170,625 disclose a hydraulic machine with a swivel angle sensor and a pressure sensor, respectively. Pressure, volume flow and power can be controlled. Summary of the invention

[0005] In contrast, the object of the present invention is to provide a hydraulic pressure medium supply assembly which is simple and cost-effective in terms of device technology and which nevertheless enables reliable and dynamic regulation and / or limitation of essential control variables and parameters of an adjustable hydraulic machine. In addition, a simple method for the pressure medium supply assembly is to be provided.

[0006] The task regarding the pressure medium supply component is achieved by a hydraulic pressure medium supply component for an open hydraulic circuit, the pressure medium supply component having a hydraulic machine and a regulating mechanism, the regulating mechanism having a regulating cylinder with a regulating piston for regulating the delivery volume of the hydraulic machine and having a pilot valve that can be controlled electrically proportionally, wherein the inflow and / or outflow into a control chamber of the regulating cylinder defined by the regulating piston can be controlled by the pilot valve so as to load the regulating piston with pressure medium for control, and an electronic control device is provided, which has at least one rated output pressure of the hydraulic machine and / or a rated delivery volume or a rated swivel angle of the hydraulic machine as input variables and has a control valve for the control chamber. The invention relates to a method for controlling a pilot valve as an output variable, wherein the control device has a first control circuit for an actual output pressure of the hydraulic machine and / or for an actual delivery volume or an actual swivel angle of the hydraulic machine, characterized in that the control device has a second control circuit for a delivery volume control speed or a swivel angle control speed of the hydraulic machine, which is arranged below the first control circuit, and has an actual delivery volume control speed or an actual swivel angle control speed of the hydraulic machine as an input variable and the second control circuit has a control variable for the pilot valve as an output variable, wherein a control value in the form of a setpoint delivery volume control speed or a setpoint swivel angle control speed is fed from the first control circuit to the second control circuit. In addition, the method is solved by a method having a hydraulic pressure medium supply assembly as described above, wherein the pilot valve is controlled by means of a first and a second control circuit.

[0007] Advantageous developments of the invention are explained in detail below.

[0008] According to the present invention, a hydraulic pressure medium supply assembly for an open hydraulic circuit, in particular for a mobile working machine, is provided. The pressure medium supply assembly can have a hydraulic machine and a regulating mechanism. The regulating mechanism is preferably used to adjust the delivery volume of the hydraulic machine. For this purpose, a regulating cylinder with a regulating piston is provided. In addition, the regulating mechanism has a pilot valve that can be electrically proportionally controlled. The inflow and / or outflow in the control chamber defined by the regulating piston of the regulating cylinder can be controlled by the pilot valve so as to load the regulating piston with pressure medium for control. In addition, the pressure medium supply assembly preferably has an electronic control device. The electronic control device further preferably has at least one rated output pressure of the hydraulic machine as an input variable. Alternatively or additionally, the rated delivery volume of the hydraulic machine can be set as an input variable for the control device. It is conceivable that one or more rated parameters are determined or alternatively the rated parameters can also be designed in an adjustable manner so that they can be matched as needed, for example, during operation. The regulating parameter for the pilot valve is preferably set as an output parameter of the control device. In addition, the control device can have a first control loop for the actual output pressure of the hydraulic machine. The first control loop is preferably tapped between the high-pressure connection of the hydraulic machine and the main control valve for the load. Alternatively or additionally, the first control loop can be set for the actual delivery volume of the hydraulic machine. If the hydraulic machine is an axial piston machine with an adjustable swing cradle or swash plate for setting the delivery volume, the actual delivery volume can be detected, for example, by corresponding devices, such as a swing angle sensor, such as a displacement sensor for adjusting the piston. As an alternative to the displacement sensor, the swing angle of the swash plate on the swing shaft can also be measured by a Hall sensor. In other words, a measuring device for detecting the displacement position or displacement is provided. It is also conceivable to determine the swing angle by measuring the torque and pressure of the drive shaft. Preferably, the second control loop is placed below the first control loop, and the second control loop can be set for the delivery volume adjustment speed. The actual delivery volume adjustment speed of the hydraulic machine, especially as a derivative of the actual delivery volume, is preferably set as an input variable for the second control loop. If the actual delivery volume adjustment speed is obtained by the actual delivery volume, the detected actual delivery volume can be advantageously used not only for the first control loop but also for the second control loop, thereby not needing to detect the actual delivery volume adjustment speed separately. The output variable of the second control loop is preferably a control variable for the pilot valve. Advantageously, a control value in the form of a delivery volume control speed from the first control loop can be fed to the second control loop. The control value from the first control loop can then be a setpoint variable for the second control loop.

[0009] The advantage of this solution is that an electronically controllable hydraulic machine for mobile applications in an open circuit is proposed, which has a simple pump control mechanism without hydraulic mechanical feedback. In contrast to the prior art, it is not necessary to detect the position of the control piston of the pilot valve, so that corresponding components can be omitted, thereby reducing costs and device technology expenses. As a result, the pressure medium supply component is extremely simple and cost-effective. By taking into account the actual delivery volume adjustment speed, the dynamic characteristics of the system are taken into account when controlling the pilot valve. The control variable of the pilot valve is therefore also dependent on the delivery volume adjustment speed, which leads to a high control quality.

[0010] In a further embodiment of the invention, the first control circuit preferably has an actual delivery pressure of the hydraulic machine and / or an actual delivery volume of the hydraulic machine as input variables.

[0011] In addition, the first control loop of the control device can be constructed for the actual torque of the hydraulic machine. Then, for example, the rated torque and the actual torque are set as input variables for the control device. Alternatively or additionally, it is conceivable that the first control loop of the control device is constructed for the actual power while taking into account the actual speed of the hydraulic machine. It is also conceivable to determine the actual power or the actual torque from the actual speed via a characteristic curve in order to then control the actual power. In order to control the actual torque, a controller, in particular a P-controller, can be provided. Alternatively, it is conceivable that the controller is constructed as a PI controller or a PID controller.

[0012] In another embodiment of the present invention, the first control loop has a control variable for the actual output pressure of the hydraulic machine and / or for the actual delivery volume of the hydraulic machine and / or for the actual torque of the hydraulic machine. Then, the control device can provide a separate control, which has a minimum value generator for the output control variable of the first control loop. The output variable of the minimum value generator is preferably a control value in the form of a delivery volume control speed, which is fed to the second control loop. The minimum value generator ensures that only the controller assigned to the desired working point is automatically activated. For example, the minimum value generator selects the minimum control variable of the fed control variables and then feeds the control variable as the set delivery volume control speed to the second control loop below.

[0013] For the delivery volume of the hydraulic machine or the swivel angle from which the delivery volume can be determined, the first control loop preferably has a controller. The controller is preferably a P-controller, for example. Alternatively, the controller can be designed as a PI controller or a PID controller. The controller can have a setpoint swivel angle and an actual swivel angle or a setpoint delivery volume or an actual delivery volume as input variables.

[0014] Preferably, a filter, for example in the form of a PT1 element or a higher-order filter, is provided for the actual swivel angle. Stabilization of the signal can be achieved in a simple manner by means of the filter.

[0015] Preferably, the first control circuit has a controller for the actual output pressure of the hydraulic machine. As input variables, the actual output pressure detected by the pressure sensor and the rated output pressure are fed to the first control circuit. Preferably, a PID controller is provided as the controller. Alternatively, a P-controller or a PI-controller can be used. The rated output pressure of the hydraulic machine is preferably adjustable. In particular, in order to determine the rated output pressure, the actual load sensing (LS) pressure of the load supplied with pressure medium via the pressure medium supply component is detected. In particular, the actual LS pressure refers to the highest actual load pressure of the load. The actual LS pressure is preferably fed as an input variable to the control device or the controller for the actual output pressure. In the load sensing (LS) control device, the highest load pressure of the regulating pump should be notified and the regulating pump should be regulated so that there is an actual output pressure in the pump line that is higher than the highest actual load pressure by a certain pressure difference (delta_p). It is therefore advantageously provided that the rated differential pressure is additionally fed as an input variable to the controller for the actual output pressure. The setpoint output pressure can then be calculated by adding the actual LS pressure to the setpoint differential pressure and used as an input variable for the regulator. The setpoint differential pressure can be fixedly parameterized or can be flexibly adjustable and predefined as a parameter.

[0016] In particular, it is also conceivable to detect a plurality of actual LS pressures and to carry out a maximum value formation or prioritization in the control device. This can be achieved by feedback to the main valve or main control valve, for example when the delivery volume of the hydraulic machine (pump) is limited and the delivery volume conducted via the main valve can therefore be limited, thereby enabling, for example, prioritization of the hydraulic steering in the event of a shortage of supply. In addition to the LS pressure control, the hydraulic machine (pump) is advantageously set to a minimum amount in order to ensure steering capability even in the event of erroneous information from the pressure sensor. In other words, the LS pressure can be regarded as a control variable, as a function of which the hydraulic machine is regulated. In addition, it is conceivable to set a minimum amount as a function of the steering requirement, thereby maintaining steering capability even in the event of erroneous information about the LS pressure.

[0017] In a controller for the actual output pressure and / or for the actual delivery volume and / or for the actual torque, an I component can be specified, such as, for example, in a PID controller, which has been explained above. Then, in particular when using a minimum value generator, it can be specified that in one or more controllers that are not activated and have an I component, the I component is frozen or, in particular, partially or completely reset. If the controller is subsequently activated, the I component is used in the usual way and the controller can react immediately. This results in that, when not activated, the I component of one or more controllers is not raised (aufziehen). This design can be called "anti-windup", i.e., it combines the freezing and resetting of the I component.

[0018] One or more filters with pressure-dependent filter coefficients can advantageously be provided for the controller of the actual output pressure. The corresponding filters are, for example, variable PT1 filters or filters of higher order. Preferably, the filter or the corresponding filter is provided for the actual output pressure and / or for the actual LS pressure. The pressure-dependent filter is preferably designed such that the filtering is reduced when the actual output pressure of the hydraulic machine increases and, conversely, the filtering is increased when the actual output pressure of the hydraulic machine decreases in order to influence the dynamic characteristics of the control.

[0019] Alternatively or additionally, one or more filters, in particular with pressure-dependent filter coefficients, can be used for the other controllers listed above and below, in particular for one or more input variables.

[0020] Alternatively or additionally, it is conceivable to provide an asymmetrical filter for the controller of the actual output pressure and / or for one or more of the controllers listed above and below, in particular for one or more input variables. This depends on the direction of the swivel of the swash plate. That is, the filtering in the first swivel direction is different than the filtering in the second swivel direction.

[0021] In another embodiment of the invention, a gain factor (Kp) is provided, in particular for the controller for the actual output pressure, which is related to the actual temperature of the pressure medium of the hydraulic machine, in particular the pressure medium on the output side, and / or to the actual rotational speed of the hydraulic machine and / or the actual output pressure of the hydraulic machine and / or to a predefined pressure gradient or a setpoint pressure gradient, in particular for the setpoint output pressure of the hydraulic machine. The gain factor can therefore be determined as a function of these variables. The gain factor can then be multiplied by a control deviation, for example in the controller, wherein the control deviation is, for example, the setpoint differential pressure minus the actual differential pressure, and wherein the actual differential pressure is equal to the actual LS pressure minus the actual output pressure. It is preferably provided that the lower the actual temperature, the smaller the gain factor, because thereby preferably in the cold state of the hydraulic machine, vibrations of the hydraulic machine can be prevented or at least reduced. Correspondingly, it can also be applied conversely that the greater the actual temperature, the greater the gain factor. Alternatively or additionally, it can be provided that the smaller the actual rotational speed of the hydraulic machine, the greater the gain factor, because the pressure buildup depends on the volume flow and therefore on the rotational speed of the hydraulic machine. Correspondingly, it can also be applied here conversely that the greater the actual rotational speed, the smaller the gain factor. Alternatively or additionally, it can be provided that the greater the pressure gradient of the nominal output pressure, the greater the gain factor. This is advantageous because the greater the pressure gradient, the greater the requirement for swinging the hydraulic machine and the hydraulic machine must therefore react faster than in the small signal range. Conversely, it can also be applied here that the smaller the pressure gradient, the smaller the gain factor. Alternatively or additionally, it can be provided that the greater the actual output pressure, the greater the gain factor. This is advantageous because, at higher actual output pressures, the control section dynamics are also higher. As a result, the hydraulic machine can swing faster without becoming unstable. Conversely, the same relationship applies.

[0022] The gain factor can advantageously be designed as a control parameter that depends on the operating point. For pressure control and / or for torque control and / or for swivel angle control, for example, it can be applied that the greater the actual output pressure, the greater the gain factor or the gain factor increases until a predetermined actual output pressure is reached and then decreases again when the actual output pressure increases further. In other words, a gain factor can also be set in the controller for the actual output pressure and / or for the actual torque, in particular for the actual variable. In other words, a pressure-dependent adaptation of the control loop amplification can be set in particular. Therefore, the control parameters are adaptable during operation of the pressure medium supply component. Advantageously, the control dynamics and / or control stability are adapted to the requirements during operation.

[0023] In another embodiment of the present invention, it can be provided that a setpoint pressure gradient is set for the regulator of the actual output pressure. The setpoint pressure gradient is preferably adaptable and adjustable. Then, the setpoint pressure gradient can have an influence on the setpoint output pressure, for example. For example, one influence is such that the higher the setpoint pressure gradient is, the faster the hydraulic press should swing out. The higher the setpoint pressure gradient is, the faster the requirement increases than the actual gradient, so that the hydraulic press swings faster in order to reach the setpoint pressure gradient. It is conceivable that the setpoint pressure gradient is used as a boundary of the setpoint output pressure or as a boundary of the change of the setpoint output pressure.

[0024] In another embodiment of the invention, the first control circuit preferably has a controller for the actual torque or actual power, which is based on the product of the actual torque and the actual speed. The actual speed can be provided as an input variable, which is measured by the drive shaft of the hydraulic machine, in particular by a speed sensor. The actual torque or absorption torque of the hydraulic machine (pump) can then be calculated from the actual speed. The actual torque is calculated by multiplying the actual swivel angle by the actual output pressure and dividing it by the hydraulic machine efficiency.

[0025] The hydraulic efficiency is a function of the actual output pressure, the actual swivel angle and the actual rotational speed and can be determined, for example, via a characteristic curve. In addition, the setpoint torque can be predefined for the controller. The control variable on the output side of the controller is preferably fed to the minimum value generator. The characteristic curve for determining the actual torque depends, for example, on the actual pressure and / or the actual swivel angle. In other words, the instantaneous power can be calculated by the controller, especially when the actual rotational speed is also taken into account.

[0026] In another embodiment of the invention, the actual variable or a part of the actual variable and one or more derivatives thereof for the first and second control loops are filtered to stabilize the signal. For example, as described above, PT1 elements or variable PT1 elements are used here.

[0027] In another embodiment of the present invention, it is conceivable to provide a delivery volume control speed preset value or a maximum delivery volume control speed for the control device, which delivery volume control speed preset value or the maximum delivery volume control speed is fed to the second control loop, in particular downstream of the minimum value generator. In particular, the delivery volume control speed preset value is fed to the control device via a control element. The control element preferably has a control value from the first control loop as an input variable, i.e., a control value output by the minimum value generator. The delivery volume control speed preset value can be set as a further input variable. Then, the final rated delivery volume control speed for the second control loop can be set as an output variable of the control element. By means of an additional predetermined, for example adjustable delivery volume control speed preset value, the control value of the minimum value generator is particularly limited in order to influence the control dynamics of the pressure medium supply component. The delivery volume control speed preset value can, for example, refer to a positive or negative maximum value of the delivery volume control speed. The higher the final rated delivery volume control speed, the faster the hydraulic press can be swung out.

[0028] By means of the adjustable setpoint pressure gradient and / or adjustable delivery volume control speed preset value explained above, the control dynamic characteristics of the pressure medium supply component can be influenced in a simple manner. Thus, the control force for the pilot valve can depend on the setpoint pressure gradient and / or the delivery volume control speed preset value. These values ​​can be matched in a variable manner during operation. Thus, a matching of the control dynamic characteristics in accordance with the requirements can be carried out during operation, and for example, it is related to the operating point or working point. Therefore, the pump dynamic characteristics can be limited and / or matched by one or more values. The swing angle and / or delivery volume control speed of the hydraulic machine can then be regulated in such a way that one or more setpoint values ​​are not exceeded. In other words, the dynamic characteristics of the pressure medium supply component can be matched by software parameters using adjustable parameters (setpoint pressure gradient and / or adjustable delivery volume control speed preset value), thereby, for example, soft or hard machine characteristics can be set. For sub-functions, the dynamic characteristics can also be changed. One sub-function can be matched to the setpoint pressure gradient and another sub-function can be matched to the delivery volume control speed preset value. Vibration reduction can also be achieved by matching the dynamic characteristics. Furthermore, sudden movements can be avoided. It has been shown that hydraulic pressure medium supply components lead to an increase in efficiency, in particular through a lower consumption of control oil.

[0029] A further advantage of the hydraulic pressure medium supply assembly is easier integration compared to a hydromechanical controller, since, for example, connecting lines or hoses to the hydromechanical controller of the variable displacement pump are omitted.

[0030] In another embodiment of the present invention, a pre-control and / or automatic calibration of the neutral current of the actuator for the pilot valve can be provided. In other words, there can be a neutral signal value for the pilot valve that is pre-set depending on the pressure. The neutral signal value refers, for example, to the full control value for the pilot valve when the delivery volume regulation speed is zero. For this purpose, the actual output pressure can be acquired. Then, the neutral current can be determined therefrom, in particular by means of a family of characteristic curves. This neutral current is then preferably fed to the control variable of the control device, in particular by addition. By pre-controlling the neutral current, the control device can be relieved of the load. In other words, an automatic calibration of the neutral current can be performed. This may be necessary in order to maintain the steady state of the hydraulic machine as a function of the actual output pressure and / or viscosity of the pressure medium and / or spring dispersion (Federstreuung) and / or magnetic dispersion of the pilot valve. Thus, compensation of hardware dispersion can be achieved by automatic calibration of the neutral current.

[0031] Advantageously, a rated torque gradient is specified for the controller of the actual torque. The rated torque gradient can be configured to be, for example, adaptable and adjustable. For example, the rated torque gradient may have an influence on the rated torque. In this case, the rated torque gradient is preferably set as a boundary for the rated torque or a boundary for the change of the rated torque. It is also conceivable to control the rated torque gradient as a preset value. In this case, the rated torque can be formed based on the rated torque gradient. Then, a specified filter or prefilter can set the rated dynamic characteristics.

[0032] In another embodiment, in addition to the control device or pump control device, a superordinate machine control device can be provided, to which, for example, the actual delivery pressure and / or the actual pivot angle and / or the actual torque and / or the actual delivery volume and / or the actual delivery volume adjustment speed and / or the gradient of the actual delivery pressure and / or the maximum torque and / or the gradient of the torque change are fed.

[0033] In another embodiment of the invention, it can be provided that the valve core of the pilot valve is controlled in such a way that it temporarily or permanently performs an axial oscillating movement, in particular during the operation of the pressure medium supply assembly. The oscillating movement is preferably performed in such a way that the current switching position of the valve core is not actually influenced. In other words, a pressure-dependent adaptation and optimization of the hysteresis reduction measures (dither) is achieved, the purpose of which is to optimize the hysteresis of the pilot valve and not to influence the control dynamics by countercompensation by the dither, in particular when the controller output works in anti-phase or in-phase with the dither.

[0034] In other words, a method is disclosed which is provided for regulating the displacement and / or the torque and / or the pressure of a hydrostatic machine.

[0035] The hydrostatic machine may have a regulating device for setting its displacement. Preferably, the method has the following steps:

[0036] - detect the pre-given rated torque,

[0037] - detect the pre-given rated displacement,

[0038] - detect a pre-defined setpoint pressure,

[0039] - detect the actual displacement or the set displacement,

[0040] - Detect actual pressure or set pressure,

[0041] - Determine the actual torque or the set torque on the drive shaft of the machine.

[0042] As a next step, it can be provided that the volume flow entering or leaving the regulating device is regulated by means of a control valve in order to set the displacement based on the force difference between the control force and the force acting on the control valve in the opposite direction. The force acting on the control valve in the opposite direction to the control force can be a spring force. The control force can also be the electrical force of the solenoid valve. The machine is set as a function of the detected displacement and / or pressure and / or the set displacement and / or the set pressure and / or the set torque. The displacement is preferably set so that the minimum displacement is always set, which leads to reaching one of the set variables.

[0043] Depending on the fail-safe application, it may be preferred that the hydraulic machine be de-energized at zero stroke or at maximum stroke.

[0044] As mentioned at the beginning, the volume flow of the hydraulic machine or the regulating pump can be obtained from the swing angle of the swash plate. If the regulating pump is not driven and the regulating system is pressure-free, the regulating pump is swung to the maximum delivery volume by the spring force of the spring, for example. On the contrary, in the driving state of the regulating pump and when the pilot valve is without current and the pump outlet is closed, the regulating pump swings to zero stroke pressure. The balance between the pump pressure on the regulating piston and the spring force of the spring plus the pump pressure on the matching piston occurs at about 4 to 8 bar. Usually, the basic setting is adopted in the voltage-free control electronic device. On the contrary, it is also conceivable that in the current-free pilot valve, the regulating pump swings to the maximum delivery volume to ensure that the pressure medium is supplied to the load, such as the steering device. Preferably, a pressure-limiting valve is then provided to limit the actual output pressure of the hydraulic machine. This can be achieved, for example, by the valve characteristics of the pilot valve being reversed. Therefore, for example, the regulating cylinder connection can be connected to the tank connection on the pilot valve in the current-free state. BRIEF DESCRIPTION OF THE DRAWINGS

[0045] The preferred embodiment of the present invention is explained in detail below with the aid of the schematic drawings. It is shown in the drawings:

[0046] Figure 1 A schematic diagram shows a hydraulic pressure medium supply assembly according to a first embodiment.

[0047] Figure 2 The schematic diagram shows the Figure 1 Control device for pressure medium supply assembly in

[0048] Figure 3 A schematic diagram is shown for use according to another embodiment Figure 1 Control device for pressure medium supply assembly in Figure 4 and Figure 5 The following schematic diagrams respectively illustrate how to determine the gain factor of a controller according to an embodiment.

[0049] Figure 6a and 6b A crawler excavator is shown and a pressure medium supply assembly for the crawler excavator is shown schematically,

[0050] Figure 7a and 7b A telescopic loader is shown and a pressure medium supply assembly for the telescopic loader is shown schematically,

[0051] Figure 8a and 8b A compact excavator is shown and a pressure medium supply assembly for the compact excavator is shown in a schematic diagram, and

[0052] Figure 9a and 9b A cooler fan system is shown and a pressure medium supply assembly for the cooler fan system is shown in a schematic diagram. DETAILED DESCRIPTION

[0053] according to Figure 1A hydraulic pressure medium supply assembly 1 is shown, which has a hydraulic machine in the form of an axial piston machine 2. The hydraulic machine has a swing cradle for adjusting the delivery volume. The axial piston machine 2 can be used not only as a pump but also as a motor. The axial piston machine 2 is driven by a drive unit 4, which can be, for example, an internal combustion engine, such as a diesel engine or an electric motor. The axial piston machine 2 is connected to the drive unit 4 via a transmission shaft 6. The speed 8 of the transmission shaft 6 can be measured by a device not shown, for example, by a speed sensor and fed to the control device of the pressure medium supply assembly 1. A regulating mechanism 12 is provided for the axial piston machine 2. The regulating mechanism has a pilot valve 14. The valve core of the pilot valve can be controlled by an actuator 16 in an electric proportional manner. For this purpose, a control variable 18 is fed to the actuator 16 by a control device 20. The valve core of the pilot valve 14 is loaded with the spring force of a valve spring 22 in the direction of the basic position. Here, the spring force acts in the opposite direction to the actuator force of the actuator 16.

[0054] The axial piston machine 2 is connected to a pressure line 24 on the output side, which in turn is connected to a main control valve 26 or a valve block. The pressure medium supply between the axial piston machine 2 and one or more loads can be controlled by the main control valve. A control line 28 branches out from the pressure line 24 and is connected to a pressure connection P of the pilot valve 14. The control line 28 is constructed, for example, in the housing of the axial piston machine 2. In addition, the pilot valve 14 has a tank connection T, which is connected to the tank via a tank line 30. In addition, the pilot valve 14 has a working connection A, which is connected to a control chamber 32 of a regulating cylinder 34. The control chamber 32 is defined here by a regulating piston 36 of the regulating cylinder. Then, the swash plate of the axial piston machine 2 can be adjusted by the regulating piston 36. The displacement of the regulating piston 36 is detected by a displacement sensor 38. Alternatively or additionally, the swivel angle of the swivel cradle of the axial piston machine 2 is measured by a rotating magnetic sensor from the swivel axis of the swivel cradle. The actual delivery volume or actual displacement of the axial piston machine 2 can then be determined by the detected displacement. The actual delivery volume 40 is then reported to the control device 20. In the basic position of the valve core of the pilot valve 14, the pressure connection P is connected to the working connection A and the tank connection T is blocked. When the valve core is loaded with the actuator force of the actuator 16, the valve core moves from its basic position in the direction of the switching position, in which the pressure connection P is blocked and the working connection A is connected to the tank connection T. Thus, in the basic position of the valve core of the pilot valve 14, the regulating piston 36 is loaded with the pressure medium from the pressure line 24. In addition, a cylinder 42 is provided in the regulating mechanism 12. The cylinder has a regulating piston 44, which acts on the swash plate of the axial piston machine 2. The regulating piston 44 defines a control chamber 46, which is connected to the pressure line 24. The regulating piston 44 is loaded by the pressure medium of the control chamber 46 and by the spring force of the spring 48 so that the regulating piston loads the swash plate in the direction of increasing the delivery volume.

[0055] Furthermore, a pressure sensor 50 is provided, by which the pressure in the pressure line 24 is measured and reported to the control device 20, wherein this pressure is the actual output pressure 52. Furthermore, a pressure sensor 54 is provided, which detects the maximum actual load pressure (actual LS pressure) 56 transmitted to the control device 20.

[0056] The control device 57 is connected to the control device 20 via a CAN interface 58 in order in particular to transmit the actual rotational speed to the control device 20. It is also conceivable to feed the actual rotational speed 8 directly to the control device 20.

[0057] When the pressure medium supply assembly 1 is used, the position of the swash plate of the axial piston machine 2 is controlled by the pilot valve 14 and the regulating piston 36. The volume flow delivered by the axial piston machine 2 is proportional to the position of the swash plate. The regulating piston 44 or the counter piston preloaded by the spring 48 is continuously loaded with the actual output pressure or pump pressure. When the axial piston machine 2 does not rotate and the regulating mechanism 12 is pressure-free, the swash plate is held in the +100% position by the spring 48. When the axial piston machine 2 is driven and the actuator 16 of the pilot valve 14 is current-free, the swash plate pivots to the zero stroke pressure because the regulating piston 36 is loaded with the pressure medium of the pressure line 24. The balance between the actual output pressure on the regulating piston 36 and the spring force of the spring 48 occurs at a predetermined pressure or pressure range, for example, between 8 and 12 bar. This zero stroke operation is adopted, for example, in a voltage-free electronic device or control device 20. The control of the pilot valve 14 is realized by the control device 20, which is preferably a digital electronic device, alternatively an analog electronic device. The control device 20 processes the required control signals, as will be explained in greater detail below.

[0058] Figure 2 The function of the control device 20 is schematically shown. The control device has a first control loop 60 and a second control loop 62. The first control loop 60 has a Figure 1 , a controller 64 for the swivel angle of the swash plate of the axial piston machine 2, a controller 66 for the output pressure of the axial piston machine 2, and a controller 68 for the torque of the axial piston machine 2. The controller 64 has a rated delivery volume 70 and an actual delivery volume 40 as input variables. The regulating variable 72 is set as an output variable. The controller 66 has a rated output pressure 74 and an actual output pressure 52 as input variables. The regulating variable 75 is set as an output variable. The controller 68 has an actual torque 76 or a rated torque as an input variable. The actual torque is set as another input variable, which can be obtained, for example, by means of a characteristic curve group via an actual speed 8. The regulating variable 78 is set as an output variable for the controller 68. In the corresponding controllers 64 to 68, the input variables are respectively fed to the control elements in the form of PID controllers.

[0059] The control variables 72, 75 and 78 are fed to a minimum value generator 80. This ensures that only the controller 72, 75 or 78 assigned to the desired operating point is automatically activated. In this case, either the output pressure, the torque or the delivery volume is precisely controlled, wherein the two other variables are respectively below the predetermined rated values. The output signal of the minimum value generator 80 is then a rated value in the form of a delivery volume control speed or a rated delivery volume control speed 82. These variables are then the input variables for the second, lower control loop 62. Another input variable of the second control loop 62 is the derivative of the actual delivery volume 40, whereby the other input variable is the actual delivery volume control speed 84. The input variables 82 and 84 for the second control loop 62 are then fed to a control element in the form of a PID element 86. The control element then outputs a signal for Figure 1 The controlled variable 18 of the pilot valve 14 in FIG.

[0060] according to Figure 3 Shown for Figure 1 Another embodiment of the control device 20 of the embodiment of the invention. The control device has a regulator 88 for the delivery volume of the axial piston machine 2 (see also Figure 1 ). In addition, a regulator 90 for the output pressure of the axial piston machine 2 and a regulator 92 for the torque of the axial piston machine 2 are provided. This is part of a first control circuit 94. In addition, a second control circuit 96 for regulating the delivery volume speed of the axial piston machine 2 is provided, which is placed below the first control circuit.

[0061] The controller 88 has a control element 98 in the form of a P element. The setpoint delivery volume 70 and the actual delivery volume 40 are provided as input variables. The actual delivery volume 40 is fed via a filter in the form of a PT1 filter using the control element 98. On the output side of the controller 88, the manipulated variable 72 is provided as an output variable that is fed to the minimum value generator 80.

[0062] The regulator 90 has as input variables an actual output pressure 52, an actual LS pressure 56, a setpoint pressure difference 100 and a setpoint pressure gradient 102. The actual LS pressure 56 and the setpoint pressure difference 100 are combined by a summing element 104 to form a setpoint output pressure. The setpoint output pressure is then fed to a control element 106 in the form of a reversed PT1 element, which estimates the expected signal curve. The setpoint output pressure is then further fed to a control element 108, which has a setpoint pressure gradient 102 as a further input variable. The setpoint pressure gradient 102 then predetermines the maximum possible gradient that should be set. The setpoint output pressure is then influenced by the predetermined setpoint pressure gradient 102 via the control element 108 so that the setpoint pressure gradient 102 can be used to control the output pressure. Figure 11. The effect can be such that the higher the setpoint pressure gradient 102, the faster the swash plate of the axial piston machine 2 can be adjusted. Conversely, the smaller the setpoint pressure gradient, the slower the swash plate of the axial piston machine 2 is adjusted. After the control element 108, the setpoint output pressure is then fed to a control element 110 in the form of a PID element. The actual output pressure 52 is then provided as a further input variable for the control element 110. As an output variable of the control element 110, the control variable 75 is obtained, which is fed to the minimum value generator 80.

[0063] The actual LS pressure 56 of the controller 90 is fed to a filter 112, which is a variable PT1 filter, upstream of the summing element 104. The same applies to the actual output pressure, which is also fed to a filter 114 in the form of a variable PT1 filter upstream of the control element 110. The filters 112 and 114 have variable, in particular pressure-dependent, filter coefficients, which are explained in more detail above.

[0064] The controller 92 has an actual speed 8, an actual delivery volume 40, an actual output pressure 52 and a setpoint torque 116 as input variables. These input variables are fed to a control element 118 in the form of a P element. The control variable 78 is provided as an output variable for the control element 118, which is fed to the minimum value generator 80. After the control element 118, a control element 120 is provided for the control variable 78, which, like the control element 106, is an inverted PT1 filter. In addition, the actual speed, the actual delivery volume 40 and the actual output pressure 8 are fed to the control element 122 before being fed to the control element 118. The control element calculates an actual torque 124 based on the actual speed 8, the actual delivery volume 40 and the actual output pressure 8. This calculation is performed with the aid of a characteristic curve group of the control element 122. The characteristic curve group depends on the actual output pressure 52 fed to the control element 122. In addition, the actual delivery volume 40 is fed to the control element 122. The characteristic curve group can then be alternatively or additionally dependent on the actual delivery volume 40. In other words, the actual torque 124 is formed from the actual rotational speed 8 and the actual output pressure 52 and / or from the actual delivery volume 40. The actual torque 124 is then fed to a filter 126 in the form of a PT1 element before it reaches the control element 118.

[0065] Furthermore, the actual delivery volume 40 is fed to a filter 99 in the form of a PT1 element before it is fed to the control element 98 .

[0066] The minimum value generator 80 forms a setpoint delivery volume adjustment speed 82 from the adjustment variables 72, 75 and 78. The setpoint delivery volume adjustment speed is fed to the control element 128. The dynamic characteristics of the pressure medium supply assembly 1 can be influenced by means of the control element. For this purpose, an adjustable delivery volume adjustment speed preset value 130 is provided as a further input variable for the control element 128. For example, by means of the delivery volume adjustment speed preset value 130, the setpoint delivery volume adjustment speed 82 output from the minimum value generator 80 can be limited and / or influenced in such a way that the greater the variable 130, the faster the swash plate of the axial piston machine 2 can be swung, and vice versa. Thus, the dynamic characteristics of the pressure medium supply assembly 1 can be influenced by adjusting the delivery volume adjustment speed preset value 130 and / or by adjusting the setpoint pressure gradient 102. For example, the pressure medium supply assembly 1 can be matched to different working machines and / or different conditions of use and / or different purposes of use in a simple and cost-effective manner.

[0067] After the control element 128, the final setpoint delivery volume control speed 132 is fed as an input variable to the second control loop 96. The second control loop has a control element 134 in the form of a PI element. The actual delivery volume control speed 84 is provided as a further input variable for the control element 134. This is based on the actual delivery volume 40, which is derived in the control element 136. The derivative, i.e. the actual delivery volume control speed, is then fed to a filter 138 in the form of a PT1 filter. Before the actual variable 84 is fed to the control element 134, a control element 140 in the form of an inverted PT1 filter is then provided. The control element 134 of the second control loop 96 has a filter for Figure 1 The manipulated variable 18 of the pilot valve 14 in the summing element 142 is used as an output variable. This manipulated variable is fed to the summing element 142. A precontrol value 144 is provided as a further input variable for the summing element 142. This precontrol value is the output variable of the control element 150, which has the actual output pressure 52 as an input variable. The precontrol value 144 is then determined based on the actual output pressure 52. The summing element 142 then combines the manipulated variable 18 and the precontrol value 144 to thereby precontrol the neutral current of the pilot valve. This enables a pressure-dependent presetting of the neutral current for the Figure 1 The neutral signal value of the pilot valve 14 in . This has the advantage that the control device 20 is relieved of this control task. The final manipulated variable 146 for the pilot valve 14 is then provided as the output variable of the summing element 142 .

[0068] It can be considered that Figure 3The control element not shown in the figure is placed after the summing element 142, which has a control variable 146 as an input variable. The input variable is superimposed with the low-frequency signal by the control element, whereby the valve core of the pilot valve 14 is continuously in an axial vibrating motion to avoid the valve core from getting stuck. Then the final control variable for the pilot valve 14 is specified as the output variable of the control element. The superposition with the low-frequency signal can be called "high-frequency pulsation, Dithering". The purpose of high-frequency pulsation is to reduce the hysteresis of the pilot valve 14 by maintaining a small movement of the valve core. Here, the movement is not allowed to be too large to avoid affecting the system (for example, the pilot valve 14 vibrates too strongly, so that the swing angle or pressure also experiences vibration). The high-frequency pulsation (frequency and amplitude) is optimized so that the hysteresis is minimized and the system is not excited. The smaller the frequency and the larger the amplitude, the better the valve core is kept in motion. However, the small frequency leads to a large period duration of the superimposed "sinusoidal signal". The problem arising from this is that the period can be exactly opposite to the rated signal. If the superimposed high-frequency pulsation runs in a direction different from the setpoint signal, a delayed reaction will occur, which can be disadvantageous in pump control. However, it is possible to increase the high-frequency pulsation frequency and / or reduce the amplitude at higher pressures, because better lubrication occurs due to the pressure and the hysteresis of the pilot valve 14 decreases. This also reduces the influence of the anti-phase high-frequency pulsation and improves the control dynamics.

[0069] Figure 4 The operating point-dependent control parameters for the control device 20 are schematically shown. The control parameter is, for example, a gain factor Kp of the controller 90 for the output pressure of the axial piston machine 2. The gain factor Kp is fed to the control device 20, for example, via the control element 110. Figure 4 , the gain factor Kp can be calculated by the control element 152 according to the temperature 154 of the pressure medium of the pressure medium supply component 1. For example, the temperature is measured from the pressure medium in the pressure line 24 by a sensor. Then, for example, the gain factor Kp is obtained by a characteristic curve group. Alternatively or additionally, the gain factor can be related to the actual speed 8 by the control element 156. Here, the gain factor Kp is also obtained by the characteristic curve group. Alternatively or additionally, the following control element 158 ​​is provided, through which the gain factor Kp can be obtained by the actual output pressure 52, wherein this can also be achieved by the characteristic curve group. In addition, alternatively or additionally, the gain factor Kp can be obtained based on the set pressure gradient 102 by the control element 160. Here, the set pressure gradient 102 can be derived from the set output pressure 74 by the control element 162. If the gain factor Kp is obtained by multiple control elements 152, 156, 158, 160, then the gain factor can be combined by the control element 164 on the corresponding output side and finally output as an output variable of the control element 164.

[0070] according to Figure 5 , instead of or in addition to Figure 4 152, 156, 158, 160 shown in the figure can determine the gain factor Kp via the actual output pressure 52. For this purpose, a control element 166 is provided, in which the gain factor Kp is then determined based on the actual output pressure 52 via a characteristic curve. In this case, the greater the actual output pressure, the greater the gain factor Kp. The gain factor Kp can also be used for the controller 88 and / or 92 instead of or in addition to the controller 90.

[0071] It is also possible to consider matching Figure 3 The running time of at least one signal or a part of the signals or all signals of the control loops 94 and 96 in the embodiment can be adapted, wherein in particular the phase of the one or more signals can be adapted. This can be achieved, for example, by the control elements 106 and / or 120.

[0072] In the control element 150 , the pilot control value 144 can preferably be ascertained based on a model taking into account flow forces in the pilot valve 14 and / or magnetic properties of the actuator 16 and / or control edge properties of the valve slide of the pilot valve 14 and / or the spring rate of the valve spring 22 .

[0073] according to Figure 6a A crawler excavator is shown, which is based on Figure 6b With pressure medium supply assembly, see Figure 1 . The crawler excavator has an axial piston machine 2, which is driven by a drive unit 4 in the form of a diesel engine. The supply of pressure medium to the hydraulic cylinders 168 and 170, to the hydraulic machines 172, 174, is controlled by a main control valve 26 in order to move the crawler excavator and to control the supply of pressure medium to the hydraulic auxiliary drive 176. In this case, the crawler excavator has different input devices 178 for the operator, which are connected to the CAN bus 180. In addition, pressure sensors 182, 184 are connected to the CAN bus 180. These pressure sensors measure the actual output pressure of the axial piston machine 2. Safety valves are respectively provided on the input side of the hydraulic cylinders 168, 170, which protect the hydraulic cylinders 168, 170 when the inlet line is disconnected. As described above, the required input variables are detected by the control device 20 and in particular the pilot valve 14 is controlled. In addition, the main control valve 26 is controlled according to the signal of the input device 178 detected via the CAN bus 180.

[0074] Figure 7a Shows that according to Figure 7bA remote control device for one of the pressure medium supply components. The pressure medium supply component has two axial piston machines 2 and 186, which are driven by a drive unit 4 in the form of a diesel engine set via a common transmission shaft. The pilot valves of the axial piston machines 2 and 186 are controlled by the control device 20 as explained above. The axial piston machine 186 is used to supply pressure medium to the wheel brakes 188, the steering system 190 and the pilot oil supply device 192. The pilot oil supply device 192 is provided for the main control valve 26 and the main control valve block. The pressure medium supply of the hydraulic cylinders 168, 170, 194, 196 is controlled by the main control valve block. In addition, the hydraulic machine 198 and the hydraulic auxiliary motor 176 used are controlled by the main control valve 26. Corresponding to Figure 6a and 6b In the embodiment in FIG. 1 , an input device 178 is also provided here, which is connected to the control device 20 via a CAN bus 180 , for example.

[0075] Furthermore, a communication device 200 is provided in order to carry out wireless communication with a server and / or with a computer, for example by radio or WiFi. For example, input variables for the control device 20 can then be adapted and / or the software can be expanded or updated via the communication device 200. Furthermore, data can be sent via the communication device 200, which data include information about the state of the pressure medium supply assembly 1.

[0076] according to Figure 8a Shows that according to Figure 8b A compact excavator with a pressure medium supply assembly. Here, an axial piston machine 2 can be seen, which is driven by a drive unit 4 in the form of a diesel engine. In addition, a control device 20 is shown, which is connected to a pressure sensor 202, for example, which measures the actual output pressure of the axial piston machine 2. In addition, the control device 20 is connected to a pressure sensor 204, which measures the maximum load pressure on the main control valve 26 or the main control block. In addition, the control device 20 is connected to a displacement sensor 206 for the swivel angle of the swash plate of the axial piston machine 2 with the control device 20. In addition, the pilot valve 14 is connected to the control device 20. Five hydraulic cylinders 208 are connected to the main control valve 26. In addition, the hydraulic machines 172, 174 and the hydraulic auxiliary motor 176 are connected. Optionally, a pilot oil supply device 192 can be provided. The input device 178 can be hydraulically connected to the pressure medium supply assembly, for example, to control the main control valve 26 or via a CAN bus 180.

[0077] according to Figure 9a and 9b Show Figure 1 Possible applications of the pressure medium supply assembly 1 for fan systems. Figure 9a, an axial piston machine 2 is provided, which is driven by a drive unit 4, for example in the form of a diesel engine. The actual output pressure of the axial piston machine 2 is measured by a pressure sensor 50. A fan motor in the form of a hydraulic machine 210 is driven by the axial piston machine 2. The hydraulic machine then drives blades 212 to generate an air flow. The coolant of the circuit is then cooled by the air flow. The pilot valve 14 can be controlled by the control device 20. The control device 20 can, for example, be fed with one or more temperatures measured by sensors via the CAN bus 180. The temperature can include, for example, the temperature of the coolant in the coolant line 214 and / or the temperature of the drive unit 4 and / or the temperature of the pressure medium. It is also conceivable that other input variables are fed to the control device 20 as described above.

Claims

1. A hydraulic pressure medium supply assembly for an open hydraulic circuit, comprising a hydraulic machine (2) and a control mechanism (12), the control mechanism having a control cylinder (34) with a control piston (36) for adjusting the delivery volume of the hydraulic machine (2) and having an electrically proportionally controllable pilot valve (14), wherein: The inflow and / or outflow into a control chamber (32) of the regulating cylinder (34) defined by the regulating piston (36) can be controlled by the pilot valve (14) so ​​as to load the regulating piston (36) with pressure medium for actuation, and an electronic control device (20) is provided, which has at least one set output pressure (74) of the hydraulic machine (2) and / or a set delivery volume or a set swivel angle (70) of the hydraulic machine (2) as input variables and has a control variable for the pilot valve (14) as output variable, wherein the control device (20) has an actual output pressure (52) for the hydraulic machine (2) and / or an actual delivery volume (52) for the hydraulic machine (2) The invention relates to a first control circuit (60) for a delivery volume or an actual swivel angle (40), characterized in that the control device (20) has a second control circuit (62) for a delivery volume control speed or a swivel angle control speed of the hydraulic machine (2) arranged below the first control circuit (60), the second control circuit having the actual delivery volume control speed or the actual swivel angle control speed (84) of the hydraulic machine as an input variable and the second control circuit having a control variable (18) for the pilot valve (14) as an output variable, wherein a control value (82) in the form of a setpoint delivery volume control speed or a setpoint swivel angle control speed (82) from the first control circuit (60) is fed to the second control circuit (62).

2. The pressure medium supply assembly according to claim 1, wherein: A first control circuit (60) of the control device (20) is designed for an actual torque (8) of the hydraulic machine (2), wherein a setpoint torque (76) and an actual torque (8) are provided as input variables for the control device (20).

3. The pressure medium supply assembly according to claim 1 or 2, wherein: The first control circuit (60) outputs a control variable for an actual output pressure (52) of the hydraulic machine (2) and / or an actual delivery volume or an actual pivot angle (40) of the hydraulic machine (2) and / or an actual torque (8) of the hydraulic machine (2), wherein the control device (20) has a separate control having a minimum value generator (80) for the output control variables (72, 75, 78).

4. The pressure medium supply assembly according to claim 3, wherein: The first control circuit (60) has a controller (110) with an I component for an actual delivery pressure (52) of the hydraulic machine (2) and / or for an actual delivery volume or an actual pivot angle (40) of the hydraulic machine (2) and / or for an actual torque (8) of the hydraulic machine (2). In this case, when the controller (110) with the I component or the controller (110) with the I component is inactive, the I component is frozen or partially or completely reduced.

5. The pressure medium supply assembly according to claim 1 or 2, wherein: A setpoint pressure gradient (102) for regulating an actual output pressure (52) in the first control circuit (60) is provided as an input variable.

6. The pressure medium supply assembly according to claim 5, wherein: The setpoint pressure gradient (102) can be adjusted to match the regulation dynamics of the pressure medium supply assembly.

7. The pressure medium supply assembly according to claim 5, wherein: The nominal pressure gradient (102) is used to limit variations in the nominal output pressure.

8. The pressure medium supply assembly according to claim 1 or 2, wherein: A delivery volume control speed preset value or a swivel angle control speed preset value (130) is provided as an input variable for the control device (20), which input variable can be adjusted to match the control dynamics of the pressure medium supply component.

9. The pressure medium supply assembly according to claim 8, wherein: The delivery volume regulating speed preset value or the swivel angle regulating speed (130) is fed to a control element (128), which has a control value of the first control loop (60) in the form of a setpoint delivery volume regulating speed or a setpoint swivel angle regulating speed (82) as a further input variable, and wherein the control element (128) outputs a final setpoint delivery volume regulating speed (132) for the second control loop (96) as an output variable, the final setpoint delivery volume regulating speed being limited by the delivery volume regulating speed preset value (130).

10. The pressure medium supply assembly according to claim 1 or 2, wherein: The highest actual load pressure (56) of the loads (168, 170) supplied by the pressure medium supply component is detected as the actual load sensing pressure, i.e., the actual LS pressure (56) and fed to the control device (20) as an input variable, and wherein a set pressure difference (100) is provided as an input variable for the control device (20), wherein a set pressure for the control device (20) is determined from the actual LS pressure (56) and the set pressure difference (100), the set pressure being provided as an input variable for the first control loop (60), and / or wherein the actual LS pressure (56) of a part or all of the loads (168, 170) is detected by corresponding devices, and wherein a maximum value formation or priority determination of the actual LS pressure (56) is performed in the control device (20).

11. The pressure medium supply assembly according to claim 1 or 2, wherein: A filter (99, 112, 114, 126, 138) is provided for at least one input variable, a part of the input variables, or all the input variables of the control device (20).

12. The pressure medium supply assembly according to claim 1 or 2, wherein: A gain factor Kp or a corresponding gain factor Kp is set for the first control loop (60) for controlling the actual output pressure (52) of the hydraulic machine (2) and / or for controlling the actual delivery volume (40) of the hydraulic machine (2) and / or for controlling the actual torque (8) of the hydraulic machine (2), wherein the gain factor Kp depends on the actual temperature (154) and / or the actual rotational speed (8) of the hydraulic machine (2) and / or on the actual output pressure (52) of the hydraulic machine (2) and / or on the rated pressure gradient (102) of the hydraulic machine (2).

13. The pressure medium supply assembly according to claim 1 or 2, wherein: The neutral current of the pilot valve (14) is pre-controlled.

14. The pressure medium supply assembly according to claim 1 or 2, wherein: The valve slide of the pilot valve (14) is actuated in such a way that it temporarily or permanently executes an axial oscillating movement, wherein the frequency and amplitude of the oscillating movement can be controlled as a function of the actual output pressure.

15. A method with a hydraulic pressure medium supply arrangement according to any one of the preceding claims, wherein: The pilot valve (14) is controlled using first and second control circuits (60, 62).

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