Hydraulic circuit

Abstract

Proposed is a hydraulic circuit (1) which has an inflow connection (2) and an outflow connection (3), is configured to throttle a flow of hydraulic fluid from the inflow connection (2) to the outflow connection (3), and has a movable control element (9) by means of which a main throttle cross-section (4) through which a flow can pass can be opened up between the inflow connection (2) and the outflow connection (3), and which control element is at least partly floatingly mounted between the inflow connection (2) and a control chamber (5), wherein a bypass line (6) for hydraulic fluid exists from the inflow connection (2) to the outflow connection (3), to which bypass line the control chamber (5) is connected and in which bypass line a throttle element having a specified pressure-volume flow characteristic curve (7) and a throttle controller (8) operatively coupled to the movable control element (9) are arranged in series and are configured such that, when a pressure difference between the inflow connection (2) and the outflow connection (3) increases, said throttle element and throttle controller adapt a bypass flow through the bypass line (6), a pressure in the control chamber (5), a position of the control element (9), and / or the size of the main throttle cross-section (4), such that the movable control element (9) assumes a new equilibrium position and the main throttle cross-section (4) through which a flow can pass is adapted in accordance with the pressure difference.

Description

[0001] Hydraulic circuit

[0002] The invention relates to a hydraulic circuit which can be used, for example, as a controllable flow valve for hydraulic fluid. The hydraulic circuit can flow from an inlet connection to an outlet connection and advantageously also vice versa. Preferably, a control of the hydraulic circuit can be used to predetermine a flow-through cross-section of the hydraulic circuit. The hydraulic circuit is therefore preferably a type of throttle with which a flow of hydraulic fluid from the inlet connection to the outlet connection can be adjusted. Particularly preferably, the hydraulic circuit is a type of adjustable throttle in which a specific flow-through cross-section can be set as the operating point for a specific pressure difference between the inlet connection and the outlet connection.

[0003] In such hydraulic circuits, a behavior that responds flexibly to pressure fluctuations is usually desirable. "Flexible" response here means that, starting from a set operating point, a higher flow from the inlet port to the outlet port is permitted, at least temporarily, in the event of a pressure increase at an inlet port or an increase in the pressure difference between the inlet port and the outlet port. This behavior is particularly advantageous for preventing oscillations in higher-level systems of which the hydraulic circuit is a part.

[0004] Such yielding behavior can be achieved, for example, by a spring-loaded mounting of a hydraulic closing element in the hydraulic circuit, similar to that implemented with a spring-loaded throttle. However, particularly when the hydraulic circuit is designed for large volume flows and large acting pressures and pressure differences, considerable spring forces are required to implement a spring-loaded mounting of a hydraulic closing element that reacts accordingly within the intended pressure range and at the intended volume flows, i.e., that releases additional flow cross-section when the pressure increases and returns to the original flow cross-section before the pressure increase when the pressure subsequently drops back to its original value. A mechanical spring element for generating such large spring forces usually requires a very large amount of available installation space.

[0005] Based on this, the object of the present invention is to at least partially solve the problems described with reference to the prior art. In particular, it is intended to propose a hydraulic circuit that exhibits the desired yielding behavior without incorporating a very large spring.

[0006] This object is achieved by the invention according to the features of the independent patent claims. Further advantageous embodiments are specified in the dependent claims as well as in the description and, in particular, in the description of the figures. It should be noted that the person skilled in the art can combine the individual features in a technologically expedient manner and thus arrive at further embodiments of the invention.

[0007] What is to be described here is a hydraulic circuit with an inlet connection and an outlet connection, designed to throttle a flow of hydraulic fluid from the inlet connection to the outlet connection, with a movable control element, with which a flow-through main throttle cross-section can be released between the inlet connection and the outlet connection and which is at least partially floating between the inlet connection and a control chamber, wherein a bypass line for hydraulic fluid from the inlet connection to the outlet connection exists, to which the control chamber is connected and in which a throttle element with a predetermined pressure-volume flow characteristic and a throttle control operatively coupled to the movable control element are arranged in series and designed toWhen a pressure difference between the inlet port and the outlet port increases, a bypass flow through the bypass line, a pressure in the control chamber, a position of the control element and / or the size of the main throttle cross-section are adjusted in such a way that a new equilibrium position of the movable control element is established and the main throttle cross-section through which the flow can pass is adjusted depending on the pressure difference.

[0008] The hydraulic circuit is designed in particular as a component that can be integrated into a higher-level hydraulic system. The hydraulic circuit can, for example, be used to specifically throttle the flow of hydraulic fluid caused by a mechanical load. One possible application is the use of the hydraulic circuit in a hydraulic drive for a cable winch. The lowering of a load with the cable winch can be controlled using the hydraulic circuit described, in which the hydraulic circuit provides a flow resistance for hydraulic fluid that counteracts the mechanical load. If the load on the cable winch increases briefly, the hydraulic circuit reacts and temporarily allows a larger flow of hydraulic fluid from the inlet port to the outlet port (for the duration of the increase in the load).This feature allows for a significantly improved design of the entire cable winch system with regard to potential vibrations. This applies to many types of systems that can be improved with the hydraulic circuit described here compared to a setup with a corresponding hydraulic circuit without yielding behavior.

[0009] The hydraulic circuit has an inlet connection and an outlet connection, to each of which lines of the hydraulic system into which the described circuit is integrated can be connected. An effective pressure difference in the circuit is always the pressure difference between the inlet connection and the outlet connection, which results from the throttling effect of the hydraulic circuit described here. The movable control element is in particular a piston that is guided in a receptacle (in particular in a cylindrical receptacle). In design variants of the hydraulic circuit (described further below), the movable control element is (partially) a hollow piston, within which further components of the hydraulic circuit are arranged.

[0010] The control chamber is located on one side of the movable control element, preferably within the cylindrical receptacle for the piston.

[0011] By moving the movable control element in the receptacle, the control chamber is then enlarged or reduced in size. The movable control element fits so precisely in the receptacle that the control chamber is sufficiently sealed for the application of the hydraulic circuit described here. This can be achieved by an appropriately selected (preferably very small) gap between the movable control element and the receptacle. If necessary, additional sealing elements can be provided between the movable control element and the receptacle. The receptacle is preferably part of a housing of the described circuit.

[0012] The fact that the movable control element is floatingly mounted means that the position of the movable control element is preferably determined solely, but at least predominantly or essentially, by the pressures acting on the movable control element from both sides. The floating mounting of the movable control element is preferably implemented in the receptacle or housing of the hydraulic circuit. If necessary, the movable control element can be supported by a spring from one side or from both sides, e.g., to prevent random positioning and / or unwanted movement of the movable control element in a pressure-free state (without pressure on the inlet connection and / or the outlet connection).However, such a spring preferably generates very small forces compared to the pressures acting on the movable control element and therefore has only a minor importance for the functioning of the hydraulic circuit or does not fundamentally change the functioning.

[0013] On the other side (the side opposite the control chamber) of the movable control element, the inflow connection and / or the outflow connection are then adjacent to the movable control element.

[0014] The main throttle cross-section is opened or closed by the movable control element, depending on the position of the movable control element. A main line or a main flow path through the described hydraulic circuit preferably runs directly from the inlet port to the outlet port past the movable control element, with a main throttle cross-section between the inlet port and the outlet port being at least partially delimited by the movable control element.

[0015] A bypass flow path or bypass line branches off (in the direction of flow) from the inlet port upstream of the main throttle cross-section and flows into the outlet port downstream of the throttle. A bypass flow flow through the bypass line or bypass flow path does not pass through the described main throttle cross-section in the main flow path. In the hydraulic circuit, the total hydraulic flow from the inlet port to the outlet port is thus divided into a bypass flow flow and a main flow.

[0016] The throttle element with a predetermined pressure-volume flow characteristic can, in particular, comprise a spring-loaded throttle with such a predetermined characteristic. Depending on a specific (known) pressure drop across the spring-loaded throttle, a specific volume flow occurs because the spring-loaded throttle releases a larger flow-through cross-section depending on the pressure. For clarity, the throttle element with a predetermined pressure-volume flow characteristic will occasionally be referred to directly as a spring-loaded throttle. In principle, other types of throttles can also be used, e.g., actively controlled throttle elements, which may have a mechanical and / or even electrical actuator to perform the throttling function.The throttle element with a predetermined pressure-volume flow characteristic and the throttle control together define the bypass flow through the bypass line depending on the pressure difference between the inlet connection and the outlet connection and thus also specify the pressure in the control chamber connected to the bypass line.

[0017] The throttle control preferably has a progressive (e.g., quadratic) relationship between the pressure drop across the throttle control and the volume flow through the throttle control. In other words: For a given throttle control opening, the pressure drop across the throttle control increases disproportionately (e.g., quadratically) with the volume flow through the throttle control. In terms of fluid mechanics, the throttle control thus acts more like a type of orifice plate.

[0018] The throttle element with a predetermined pressure-volume flow characteristic preferably has a linear relationship between the pressure drop occurring across the throttle element with a predetermined pressure-volume flow characteristic and the volume flow flowing through the spring-loaded throttle, and vice versa. In other words, the pressure drop across the throttle element with a predetermined pressure-volume flow characteristic increases linearly with the volume flow, and vice versa.

[0019] The throttle control is operatively coupled to the movable control element. This coupling is preferably bidirectional. This means that an adjustment of the throttle control and a movement of the control element must always occur simultaneously. When the movable control element is in a certain position, the throttle control has a specific cross-section that dictates a specific pressure-volume flow characteristic. As the flow-through cross-section of the main throttle increases, the flow-through cross-section of the throttle control increases simultaneously, thus increasing the permeability of the bypass line for hydraulic fluid.

[0020] Due to this active coupling, the position of the movable control element, the bypass flow through the bypass line and the pressure difference between the inlet connection and the outlet connection are related in such a way that a larger flow-through main throttle cross-section is released at a larger pressure difference.

[0021] It is particularly advantageous if a first effective area of ​​the movable control element for a pressure in the inlet connection is smaller than a second effective area for a pressure in the control chamber.

[0022] The first effective area on the movable control element is the area across which a pressure acting in the inlet connection acts on the movable control element. A pressure present in the inlet connection generates a force on the movable control element via the first effective area. The second effective area forms a wall section of the control chamber. A pressure acting in the control chamber generates a force on the movable control element via the second effective area. Because the second effective area is larger than the first effective area, a force acting on the movable control element from the control chamber is greater than a force acting on the movable control element from the inlet connection when the pressures at the inlet connection and in the control chamber are the same.For this reason, the control element is in a position deflected as far as possible towards the inlet port when the bypass line behind the control chamber is closed. The pressure in the inlet port then continues via the bypass line into the control chamber. Hydraulic fluid cannot flow from the control chamber via the bypass line into the outlet port and thus reduce the pressure in the control chamber. Preferably, the main throttle cross-section of the main flow path through which flow can occur is then closed. Due to the design, the pressure in the control chamber cannot be quasi-statically higher than the pressure in the inlet port because the inlet port forms a pressure reservoir from which the control chamber is fed with pressure.However, because the second effective area is larger than the first effective area, it is still possible to generate forces acting on the movable control element with the control chamber, which can move the movable control element against the pressures acting at the inlet connection.

[0023] It is also advantageous if a differential area, which corresponds to a difference between the second effective area and the first effective area, is connected to the outflow connection.

[0024] Due to design reasons, it is usually necessary for the movable control element to have a cross-section that widens from the second active surface towards the first active surface. Such a widening cross-section necessarily means that there is also a differential surface between the first active surface and the second active surface. Such a differential surface is fundamentally always subject to pressure, so that forces acting on the movable control element originating from the differential surface. The aim is that these forces acting on the movable control element via the differential surface do not reach the forces acting on the movable control element at the first active surface and the second active surface that are relevant for the hydraulic circuit described here, or do not exceed them to such an extent that the function of the movable control element and the circuit is impaired.For this reason, it is desirable for the pressure level at the differential surface to be as low as possible. Such a low pressure level could, for example, be the environment of the hydraulic circuit. However, this is disadvantageous because a leak at the sealing surfaces of the movable control element would then cause hydraulic fluid to leak into the environment. In other design variants, the differential surface could also be connected to a leakage line that provides a lower pressure level. Due to the throttling effect of the circuit described here, the pressure level at the outlet port is always below the pressure level at the inlet port and in the control chamber. For this reason, it is advantageous to apply the pressure at the outlet port to the differential surface. This pressure is always below the pressure at the inlet port.

[0025] The second effective surface, on which the pressure in the control chamber acts, is arranged on one side of the movable control element. The first effective surface and the differential surface, which together are the same size as the second effective surface, are arranged on the other side of the movable control element. The pressure at the inlet port acts on the first effective surface, and the pressure at the outlet port acts on the differential surface. If necessary, the control element can also have additional surfaces on which pressures act, which, however, do not fundamentally change the functioning of the device described here.

[0026] Furthermore, it is advantageous if the throttle element with a predetermined pressure-volume flow characteristic is designed as a spring-loaded check valve.

[0027] The throttle element with a predetermined pressure-volume flow characteristic is preferably designed to specifically release hydraulic fluid from the control chamber depending on a pressure difference between the control chamber and the outlet connection in order to regulate the pressure level in the control chamber.

[0028] The throttle control is preferably designed to allow hydraulic fluid from the inlet connection into the control chamber in a targeted manner depending on a pressure difference between the inlet connection and the control chamber in order to regulate the pressure level in the control chamber.

[0029] It is further advantageous if the bypass line has a first section from the inflow connection to the control chamber and a second section from the control chamber to the outflow connection, wherein the throttle control is arranged in the first section and the throttle element with a predetermined pressure-volume flow characteristic is arranged in the second section.

[0030] In variant designs, the control chamber can also be connected to the bypass line via a branch line, wherein the branch line preferably branches off from the bypass line between the throttle control and the throttle element with a predetermined pressure-volume flow characteristic curve.

[0031] When the movable control element is in a specific position, the volume flows through the first and second sections of the bypass line must be equal. For this reason, the throttle control will always move to a position where the pressure-volume flow characteristic of the throttle control intersects the pressure-volume flow characteristic of the throttle element with a specified pressure-volume flow characteristic pressure difference.

[0032] The throttle control can adjust by changing the position of the movable control element, releasing a larger cross-section through which hydraulic fluid can flow into the bypass line. The pressure-volume flow characteristic of the throttle element, with its predefined pressure-volume flow characteristic, thus determines the position of the movable control element depending on the pressure difference (between the control chamber and the outlet connection) across the throttle element with its predefined pressure-volume flow characteristic. The position of the throttle control adjusts so that a corresponding amount of hydraulic fluid flows into the control chamber.

[0033] Through the active coupling of the throttle control with the movable control element, the flow-through main throttle cross-section is adjusted accordingly. The characteristic curve of the throttle element with a predetermined pressure-volume flow characteristic indirectly specifies the flow-through main throttle cross-section as a function of the pressure difference between the control chamber and the outlet connection. In the case that the throttle element with a predetermined pressure-volume flow characteristic is a spring-loaded throttle, a very small spring of the spring-loaded throttle can specify the pressure dependence of the main throttle cross-section. This spring can be very small in comparison to the spring that would be necessary to achieve the corresponding behavior with a direct action of the spring on the movable control element.This also means that the main throttle cross-section through which the flow can be carried in the main line depends on the pressure difference between the inlet connection and the outlet connection.

[0034] It is also advantageous if a pressure-volume flow characteristic curve of the throttle element with a predetermined pressure-volume flow characteristic curve has a proportional and linear course, so that a pressure loss occurring at the throttle element with a predetermined pressure-volume flow characteristic curve increases proportionally with an increasing volume flow of hydraulic fluid through the bypass line.

[0035] The volume flow of hydraulic fluid outflow from the control chamber into the outlet port is proportional to a pressure difference between the pressure in the control chamber and the pressure at the outlet port.

[0036] The characteristic curve of the throttle element with a predefined pressure-volume flow characteristic can also deviate from a linear curve. However, it is important that the outflow of hydraulic fluid through the throttle element with a predefined pressure-volume flow characteristic increases more sharply with increasing pressure than it does with the throttle control. This ensures that an increase in pressure at the throttle element with a predefined pressure-volume flow characteristic allows the throttle control to adjust in such a way that the movable control element moves and releases a larger flow-through main throttle cross-section.

[0037] It is particularly advantageous if a pressure-volume flow characteristic curve of the throttle control has a disproportionate course, so that a pressure loss occurring at the throttle control increases disproportionately with an increasing volume flow of hydraulic fluid through the bypass line.

[0038] Thus, for a constant throttle position, the volume flow into the control chamber is relatively large relative to the pressure difference at low pressure differences. At larger pressure differences, this volume flow decreases relative to the pressure difference. The volume flow increases less than proportionally to the pressure difference.

[0039] The pressure loss across the throttle control and the pressure loss across the throttle element with a specified pressure-volume flow characteristic together correspond to the pressure difference between the inlet connection and the outlet connection.

[0040] The pressure in the control chamber is set between the pressure at the inlet port and the pressure at the outlet port.

[0041] Due to a given pressure difference between the inlet connection and the outlet connection, a position of the movable control element is established in which a bypass volume flow through a first section of the bypass line and a bypass volume flow through a second section of the bypass line are equal and the resulting position of the movable control element is predetermined by the pressure-volume flow characteristic of the throttle element with a predetermined pressure-volume flow characteristic and the pressure-volume flow characteristic of the throttle control such that the main throttle cross-section through which the flow can pass is dependent on the pressure-volume flow characteristic of the throttle element with a predetermined pressure-volume flow characteristic.

[0042] For a given pressure difference between the inlet connection and the outlet connection, an equilibrium position is always established after some time, in which the bypass volume flow in the bypass line upstream and downstream of the control chamber (in a first section and in a second section of the bypass line) is uniform. This equilibrium position is described here and is predetermined by the pressure-volume flow characteristics of the throttle control and the throttle element with a predetermined pressure-volume flow characteristic. It is also advantageous if the throttle control is designed with a notch that interacts with the movable control element in such a way that an adjustment of the flow-through main throttle cross-section simultaneously adjusts the flow-through bypass cross-section of the throttle control.

[0043] The flow-through bypass cross-section describes the size of a flow-through passage or an opening of the throttle control that throttles the flow. The adjustment of the flow-through main throttle cross-section and the bypass cross-section to each other is preferably designed such that an adjustment of the flow-through main throttle cross-section simultaneously increases the bypass cross-section, and vice versa.

[0044] Furthermore, it is advantageous if the notch is arranged on the movable control element or on a further component, wherein the movable control element and the further component together are designed to also adapt a bypass cross-section of the throttle control when adapting the main throttle cross-section through which the flow can pass.

[0045] It is further advantageous if a pressure-volume flow characteristic curve of the throttle control has a disproportionate behavior at a predetermined position of the movable control element, so that a pressure loss occurring at the throttle control increases disproportionately with an increasing volume flow of hydraulic fluid through the bypass line.

[0046] In a particularly advantageous embodiment, the hydraulic circuit has a pilot piston that can be positioned by a controller to specify an operating point of the hydraulic circuit, which specifies an opening width of the main throttle cross-section at a given pressure difference between the inlet port and the outlet port. It is also advantageous if a control valve is arranged in a second section of the bypass line between the control chamber and the outlet port, with which a flow-through cross-section can be adjusted and an operating point of the hydraulic circuit can be specified.

[0047] The control valve can be an adjustable throttle. The control valve and the throttle control element with a predefined pressure-flow characteristic can together form an overall system whose pressure-flow characteristic can be adjusted to be steeper or flatter to define an operating point of the hydraulic circuit.

[0048] Particularly preferably, there is an additional feedback loop between the control valve and the throttle control or the movable control element, or the active coupling between these two components. This active coupling is preferably configured such that the response behavior of the hydraulic circuit to increases in the pressure difference between the inlet port and the outlet port remains the same regardless of the operating point. Regardless of how far the main throttle cross-section is already open, a similar increase in the pressure difference preferably leads to the same expansion of the main flow path.

[0049] Preferably, the feedback is designed such that the opening width of the main throttle cross-section follows the opening width of the control valve and the operating point of the throttle control is independent of the specific position of the movable control element or that the pressure-dependent behavior of the hydraulic circuit is independent of the opening width of the main throttle cross-section set via the control valve.

[0050] Preferably, the throttle control and / or the control valve are arranged between a pilot piston and the movable control element. Particularly preferably, the throttle element is configured with a predetermined pressure-volume flow characteristic curve such that the pressure-volume flow characteristic curve is independent of the position of components of the hydraulic circuit.

[0051] The throttle element with a predetermined pressure-volume flow characteristic can, for example, be designed as a spring-loaded throttle or as a check valve within a pilot piston of the hydraulic circuit.

[0052] Preferably, the throttle control is formed with a notch in the pilot control piston and / or in the movable control element, which can be further opened or closed by a displacement of the respective other component (movable control element or pilot control piston).

[0053] Particularly preferably, both the throttle control and the control valve are formed between a pilot control piston and the movable control element. This preferably ensures that the properties of the throttle element and particularly preferably also the properties of the control valve remain the same regardless of the opening width of the main throttle cross-section. Particularly preferably, the main throttle cross-section is thus directly determined by the position of the pilot control piston. Particularly preferably, the movable control element follows the pilot control piston at a given pressure difference between the inlet port and the outlet port.

[0054] Particularly preferably, the hydraulic circuit is designed such that when the pressure at the outlet connection exceeds the pressure at the inlet connection, the movable control element is movable such that a flow-through main throttle cross-section is released and a flow of the hydraulic fluid from the outlet connection to the inlet connection is permitted.

[0055] The invention and the technical context of the invention are explained in more detail below with reference to the figures. The figures show preferred embodiments to which the invention is not limited. It should be noted in particular that the figures, and in particular the proportions depicted in the figures, are only schematic. They show:

[0056] Fig. 1 : schematically shows a first embodiment of a described hydraulic circuit;

[0057] Fig.2: schematically shows a second embodiment of a described hydraulic circuit;

[0058] Fig. 3a: a diagram of pressure-volume flow characteristics of the throttle control and the throttle element with a predetermined pressure-volume flow characteristic;

[0059] Fig. 3b: a diagram showing the relationship between the pressure-volume flow characteristics according to Fig. 3a;

[0060] Fig. 4: a hydraulic circuit diagram of an embodiment variant of a described hydraulic circuit;

[0061] Fig. 5: a hydraulic circuit diagram of a further embodiment of a described hydraulic circuit;

[0062] Fig. 6: a hydraulic circuit diagram of yet another embodiment of a described hydraulic circuit;

[0063] Fig. 7: a hydraulic circuit diagram of yet another embodiment of a described hydraulic circuit;

[0064] Fig. 8: a hydraulic circuit diagram of yet another embodiment of a described hydraulic circuit;

[0065] Fig. 9: a hydraulic circuit diagram of yet another embodiment of a described hydraulic circuit; Fig. 10: a hydraulic circuit diagram of yet another embodiment of a described hydraulic circuit;

[0066] Fig. 11: a diagram of pressure-volume flow characteristics of the throttle control and the throttle element with a predetermined volume flow characteristic for the embodiment according to Fig. 10;

[0067] Fig. 12: a sectional drawing through a variant of a described hydraulic circuit; and

[0068] Fig. 13: a modification of the embodiment of a described hydraulic circuit according to Fig. 9.

[0069] Fig. 1 and Fig. 2 show two different embodiments of the described hydraulic circuit 1. Hydraulic fluid can flow through the circuit from the inlet port 2 to the outlet port 3. The circuit is designed such that, depending on the pressure (with an increase in pressure at the inlet port 2 or with an increase in the pressure difference between the inlet port 2 and the outlet port 3), the flow-through cross-section of the hydraulic circuit 1 increases, so that the hydraulic circuit 1 responds flexibly to an increased hydraulic load / increased pressure load.

[0070] The hydraulic circuits 1 according to Figs. 1 and 2 differ in that the inlet connection 2 and the outlet connection 3 are interchanged. This means that other components in the hydraulic circuits 1 according to Figs. 1 and 2 are also arranged differently.

[0071] The hydraulic circuits 1 each have a flow-through main throttle cross-section 4, through which a main flow path 22 runs from the inlet port 2 to the outlet port 3. The majority of the hydraulic fluid flows through the main flow path 22 on the way from the inlet port 2 to the outlet port 3. A smaller portion of the hydraulic fluid flowing through the hydraulic circuit 1 is branched off into a bypass line 6 and flows along a bypass flow path 23 through the bypass line 6 from the inlet port 2 to the outlet port 3. This portion is referred to here as the bypass volume flow 24. The bypass volume flow 24 through the bypass line 6 controls the flow-through main throttle cross-section 4, so that the hydraulic circuit 1 has the desired compliant behavior.

[0072] The hydraulic circuit 1 has a movable control element 9, which can open or close the main throttle cross-section 4 through which flow passes. The movable control element 9 is mounted in a floating manner in a housing 30 of the hydraulic circuit 1. The movable control element 9 has a second active surface 12, which borders a control chamber 5. The movable control element 9 is subjected to a pressure in the control chamber 5 via the second active surface 12. The movable control element 9 also has a first active surface 11, which is subjected to the pressure at the inlet connection 2. The second active surface 12 is larger than the first active surface 11, so that when the pressure in the control chamber 5 and the pressure at the inlet connection 2 correspond, the control element 9 is moved against the pressure in the inlet connection 2 until it reaches a stop position in which the main throttle cross-section 4 through which flow passes is minimal or possibly even closed.

[0073] The control element 9 also has a differential area 19 which corresponds to the area difference between the first active area 11 and the second active area 12. A pressure acting on the differential area 19 pushes the movable control element in the same direction as a pressure acting on the first active area 11. According to Fig. 1 and Fig. 2, the differential area 19 is subjected to the pressure at the outflow connection 3, which is lower than the pressure in the control chamber 5 and the pressure at the inflow connection 2. In principle, it is not necessary for the pressure at the outflow connection 3 to act on the differential area 19. In the embodiment according to Fig. 1, this is ensured via the hydraulic connection 31. In the embodiment according to Fig. 2, this already results without such a connection 31 due to the design.

[0074] In connection with the differential surface 19, it is essential for the functioning of the hydraulic circuit 1 that the pressure at the differential surface 19 is lower than the pressure in the control chamber 5, which acts on the second active surface 12, and the pressure at the inlet connection 2, which acts on the first active surface 11, so that the pressure at the differential surface 19 does not reverse the force ratio between the pressure forces acting on the first active surface 11 and the pressure conditions acting on the second active surface 12, but at most influences it. The pressure forces acting on the differential surface 19 must not disrupt the functioning of the hydraulic circuit 1.

[0075] In order to adjust the pressure in the control chamber 5 so that the control element 9 is moved or held in the desired manner, the control chamber 5 is connected to the bypass line 6 and the bypass flow path 23 runs through the control chamber 5. A first section 13 of the bypass line 6 connects the inlet connection 2 to the control chamber 5. A second section 14 of the control chamber 5 connects the control chamber 5 to the outlet connection 3. The pressure in the control chamber 5 is thus set at a level which lies between the pressure at the inlet connection 2 and the pressure at the outlet connection 3. For the precise adjustment of the pressure level in the control chamber 5, there is a throttle control 8 in the first section 13 of the bypass line 6 and a throttle element with a predetermined pressure-volume flow characteristic curve 7 in the second section 14 of the bypass line 6, which throttle element is shown here and in the other figures as an example in the form of a spring-loaded throttle oris shown as a spring-loaded throttle valve / check valve. The throttle control 8 is coupled or connected to the control element 9, so that a displacement of the control element 9 also causes a change in the throttling effect of the throttle control 8, so that a volume flow of hydraulic fluid entering an inlet 17 of the bypass line 6 or into the first section 13 of the bypass line 6 changes as a result of a change in the position of the movable control element 9. As a result, the pressure in the control chamber 5 also changes. An operative coupling 18 between the throttle control 8 is formed according to Fig. 1 by the extension 33 on the movable control element 9, which connects the movable control element 9 to the closing element 32 of the throttle control 8. In Fig. 2, this operative coupling 18 is not shown separately, because here the throttle control 8 is formed directly on the movable control element 9.

[0076] The volume flow of hydraulic fluid escaping from the control chamber 5 through the second section 14 of the bypass line 6 is influenced by the throttle element with a predetermined pressure-volume flow characteristic curve 7. When the position of the movable control element 9 changes, the volume of the control chamber 5 changes, which can lead to differences between the volume flows through the first section 13 of the bypass line 6 and through the second section 14 of the bypass line 6 during movement of the movable control element 9. However, a new equilibrium position of the movable control element 9 is subsequently established depending on the pressure difference between the pressure at the inlet connection 2 and the pressure at the outlet connection 3. The volume flows through the first section 13 and the second section 14 of the bypass line 6 are then equal.The resulting pressure in the control chamber 5 and the resulting equilibrium position of the movable control element 9 are predetermined by the pressure-volume flow characteristics 25, 26 of the throttle control 8 and the throttle element with a predetermined pressure-volume flow characteristic 7. These pressure-volume flow characteristics 25, 26 are selected such that when the pressure difference between the inlet connection 2 and the outlet connection 3 increases, the total volume flow through the hydraulic circuit 1 (along the main flow path 22 through the flow-through main throttle cross-section 4 and along the bypass flow path through the bypass line 6) increases. This increase in the total volume flow occurs as if the bypass line 6 with the elements arranged therein were not present, but as if the control element 9 were instead loaded with a large, linearly acting spring, which acts against a pressure at the inlet connection 2.As already stated at the beginning, the inlet connection 2 and the outlet connection 3 are interchanged in the embodiments shown in Figs. 1 and 2. Consequently, the first section 13 and the second section 14 of the bypass line 6 are also interchanged. The throttle control 8 is designed differently in both variants.

[0077] In the embodiment variant according to Fig. 1, the throttle control 8 is designed with a closing element 32, which is connected to the control element 9 via an extension 33 and has a notch 16 formed in the housing 30. The notch 16 is covered by the closing element 32 to varying degrees depending on the position of the control element 9 and opens an inlet 17 into the bypass line 6 to varying degrees. Through bores 34 are provided in the closing element 32, which ensure a passage in the main flow path 22 regardless of the position of the movable control element 9.

[0078] In the embodiment shown in Fig. 2, the throttle control 8 is formed with a notch 16 on the control element 9. An inlet 17 into the bypass line 6, which is further opened or closed by a movement of the movable control element 9, is formed directly on the control chamber 5. The first section 13 of the bypass line 6 is accordingly very short.

[0079] The pressure-volume flow characteristic curve of the throttle control 25 and the pressure-volume flow characteristic curve of the throttle element 26 are now explained with reference to Fig. 3a and Fig. 3b.

[0080] In Fig. 3a, two diagrams are superimposed, namely a first diagram relating to the pressure-volume flow characteristic curve of the throttle control 25 and a second diagram relating to the pressure-volume flow characteristic curve of the throttle element 26. The first vertical axis relates to the pressure-volume flow characteristic curve of the throttle control 25. The pressure difference P2 (inlet connection) - Pöf (control chamber) present at the throttle control 8 is plotted on this axis. The second vertical axis relates to the pressure-volume flow characteristic curve of the throttle element 26. The pressure difference P5 (control chamber) - P3 (outlet connection) present at the throttle element with a predetermined pressure-volume flow characteristic curve 7 is plotted on this axis.

[0081] The scaling of the two vertical axes of the diagram according to Fig. 3a is different. However, the pressure difference P2 (inlet connection) - P5 (control chamber) and the pressure difference P5 (control chamber) - P3 (outlet connection) are proportional to one another. The relationship between the pressure difference P2 (inlet connection) - P5 (control chamber) and the pressure difference Ps (control chamber) - P3 (outlet connection) is shown in Fig. 3b. The scaling of the two vertical axes in Fig. 3a is determined according to the relationship according to Fig. 3b. The horizontal axis of the diagram according to Fig. 3a shows the volume flow which is established through the first section 13 of the bypass line 6 and through the second section 14 of the bypass line 6 when the movable control element 9 is in a certain position. Then the volume flows through the first section 13 and the second section 14 of the bypass line 6 must be equal.For this reason, the throttle control 8 will always move into a position according to which the pressure-volume flow characteristic curve of the throttle control 25 forms an intersection point with the pressure-volume flow characteristic curve of the throttle element 26 at the level of the respectively specified pressure difference P5 (control chamber)-P3 (outlet connection).

[0082] The throttle control 8 can adapt by changing the position of the movable control element 9 and release a larger cross-section through which hydraulic fluid can flow into the bypass line 6. Fig. 3a shows a total of three pressure-volume flow characteristic curves of the throttle control 25, which can be set by adjusting the throttle control 8 as a result of a given pressure difference between the inlet connection 2 and the outlet connection 3. The pressure-volume flow characteristic curve of the throttle element 26 thus specifies the position of the movable control element 9. The position of the throttle control 8 adapts in such a way that the pressure-volume flow line of the throttle control 25 forms an intersection point with the pressure-volume flow characteristic curve of the throttle element 26 in accordance with the scaling specified in Fig. 3b.By coupling the throttle control 8 with the movable control element 9, the flow-through main throttle cross-section 4 is adjusted accordingly. The characteristic curve of the (relatively) very small spring of the throttle element with a predetermined pressure-volume flow characteristic curve 7 specifies the flow-through main throttle cross-section 4 as a function of the pressure difference P5 (control chamber) - P3 (outlet connection) and thus also as a function of the pressure difference P2 (inlet connection) - P3 (outlet connection) between the inlet connection 2 and the outlet connection 3.

[0083] Figs. 4 to 9 now show circuit diagrams of various embodiments of the hydraulic circuit 1. With regard to the explanation of Figs. 4 to 9, reference is first made to the explanation of Figs. 1 and 2, which is fully incorporated herein by reference.

[0084] The coupling of the throttle control 8 to the control element 9 is represented by an active coupling 18. The embodiments shown in Figs. 1 and 2 for providing a throttle control 8 coupled to the control element 9, which is arranged in the first section 13 of the bypass line 6, are not exhaustive. Many other embodiments are conceivable. The schematic representation of the throttle control 8 in Figs. 4 to 9 can be implemented accordingly.

[0085] In the embodiments according to Figs. 4, 5, and 6, a control valve 10 is integrated into the second line section, which is connected in series with the throttle element with a predetermined pressure-volume flow characteristic curve 7. With this control valve 10, an operating point 27 of the hydraulic circuit 1 can be set. This means that for a given pressure difference between the inlet port 2 and the outlet port 3, a specific flow-through main throttle cross-section 4 can be specified, from which an increase or decrease in the pressure difference then causes an adjustment of the flow-through main throttle cross-section 4 using the special properties of the hydraulic circuit 1 described here. The arrangement of the inlet port 2 and outlet port 3 according to Figs. 4 and 5 corresponds to the arrangement of the inlet port 2 and outlet port 3 according to Fig. 1.The arrangement of inlet port 2 and outlet port 3 according to Fig. 6 corresponds to the arrangement of inlet port 2 and outlet port 3 according to Fig. 2. Figs. 4 and 5 also show that the order of the throttle element with a predetermined pressure-volume flow characteristic 7 and the control valve 10 in the second section 14 of the bypass line 6 can be varied. This also applies to the embodiment according to Fig. 6.

[0086] Fig. 7 now shows a further embodiment variant in which, although no separate control valve 10 is arranged in series with the throttle element with a predetermined pressure-volume flow characteristic curve 7, the throttle element with a predetermined pressure-volume flow characteristic curve 7 has a control connection 35 via which the throttle element with a predetermined pressure-volume flow characteristic curve 7 can be supplied with a control signal with which an operating point 27 or a characteristic curve of the throttle element with a predetermined pressure-volume flow characteristic curve 7 can be set in order to influence the behavior of the hydraulic circuit 1 in a similar way to how this is also possible with a control valve 10. Fig. 7 also shows that the movable control element 9 is prestressed with a prestressing element 15 in order to define the position of the movable control element 9 in the depressurized state and to support the pressure acting on the second active surface 12 in the control chamber 5.

[0087] Fig. 8 and 9 now show a further embodiment of the hydraulic circuit 1, in which an additional feedback 36 from the control valve 10 to the throttle control 8 or the movable control element 9 and in particular to the active coupling 18 between the movable control element

[0088] 9 and the throttle control 8. The assignment of inlet connection 2 and outlet connection 3 in Fig. 8 corresponds to Fig. 2. The assignment of inlet connection 2 and outlet connection 3 in Fig. 9 corresponds to Fig. 1. Due to this additional feedback 36, opening the control valve

[0089] 10 simultaneously determines the relationship between the position of the movable control element 9 and the opening width of the throttle control 8 such that the main throttle cross-section 4 through which the flow can pass follows the opening width of the control valve 10 and the operating point 27 of the throttle control 8 is independent of the specific position of the movable control element 9 or that the pressure-dependent behavior of the hydraulic circuit is independent of the opening width of the main throttle cross-section 4 set via the control valve 10.

[0090] Fig. 10 shows yet another variant of the hydraulic circuit. In this variant, the throttle element with a predetermined pressure-volume flow characteristic curve 7 is arranged in the first section 13 of the bypass line 6 between the inlet connection 2 and the control chamber 5. The throttle control 8 is located (unlike in the other variants) in the second section 14 of the bypass line. Otherwise, the structure of the circuit shown in Fig. 10 essentially corresponds to the structure of the circuit shown in Fig. 6.

[0091] The throttle element with a predetermined pressure-volume flow characteristic curve 7 is a flow control valve 40. A flow control valve 40 is designed to always maintain a constant volume flow regardless of the prevailing pressure difference (here, the pressure difference between the inlet port 2 and the control chamber 5). In the circuit shown in Fig. 10, the volume flow of hydraulic fluid through the bypass line 6 is therefore always constant, regardless of the pressure difference P2-P3 between the inlet port 2 and the outlet port 3.

[0092] The interactions between the throttle control 8 and the throttle element with a predetermined pressure-volume flow characteristic curve 7 are shown in Fig. 11 in a diagram based on Fig. 3a. Pressures are plotted on the Y-axis. The bypass volume flow 24 through the bypass line is plotted on the X-axis. Because the throttle element with a predetermined pressure-volume flow characteristic curve 7 is a flow control valve 40 here, the bypass volume flow 24 is constant. The pressure-volume flow characteristic curve of the throttle element 26 is a vertical line that specifies a constant bypass volume flow 24 regardless of the prevailing pressures.

[0093] The two Y-axes P5-P3 and P2-P5 are scaled relative to one another, as described in connection with Figs. 3a and 3b, such that operating points 27 of the hydraulic circuit according to Fig. 10, which can occur during operation of the hydraulic circuit according to Fig. 10, are each intersection points of the pressure-volume flow characteristic curve of the throttle element 26 and the pressure-volume flow characteristic curves of the throttle control 25. With a higher pressure difference between the inlet connection and the outlet connection, the pressure differences P5-P3 and P2-P3 also increase. As a result, the pressure-volume flow characteristic curve of the throttle element 26 must change such that the intersection point is higher and an operating point 27 is established according to the pressure difference.

[0094] According to this embodiment of the hydraulic circuit 1 according to Figs. 10 and 11, the bypass flow through the bypass line is not adjusted in the sense of an adjustment of the volume flow of hydraulic fluid through the bypass line, as is the case with the other circuits according to Figs. 1 to 9. In the hydraulic circuit 1 according to Figs. 10 and 11, the volume flow of hydraulic fluid through the bypass line is, at least theoretically, always constant due to the flow control valve 40. What changes, however, depending on the pressure difference between the inlet connection and the outlet connection, is the pressure difference P5-P3, which must be suitable for the constant bypass flow. In order for the pressure difference to match the constant bypass flow, the cross-sectional area of ​​the throttle control must become smaller as the pressure difference increases. The notch of a throttle control designed with a notch is therefore, in the embodiment according to Fig.10 and 11 in reverse to a notch of a throttle control 8 of the other embodiments according to Figs. 1 to 9. In addition, the ratio of the volume flows along the main flow path through the flow-through main throttle cross-section and the volume flow along the bypass flow path adapts. As the pressure difference between the inlet connection and the outlet connection increases, the volume flow through the bypass flow path becomes proportionally smaller. Fig. 12 and Fig. 13 show cross sections through an embodiment of the described hydraulic circuit 1. The embodiment according to Figs. 12 and 13 essentially corresponds to the structure of the circuit according to Fig. 8. Fig. 13 shows a modification of the embodiment according to Fig. 12. The reference numerals from Fig. 12 are only partially repeated in Fig. 13. With regard to the components shown in Fig. 13, reference is therefore made in part to Fig. 12 and the explanations for Fig. 12.

[0095] The hydraulic circuit 1 shown in Fig. 12 and Fig. 13 has the inlet connection 2 and the outlet connection 3. The main flow path 22 and the bypass flow path 23 from the inlet connection 2 to the outlet connection 3 are only shown in Fig. 12 and are to be understood accordingly in Fig. 13. The bypass flow path 23 runs through the bypass line 6. The bypass line 6, with the first section 13 from the inlet connection 2 into the control chamber 5 and with the second section 14 from the control chamber 5 to the outlet connection 3, has a complex course between the individual components of the hydraulic circuit 1. This course of the bypass line 6 is explained in detail below using the components arranged along the bypass line 6 (throttle control 8, control chamber 5 and throttle element with a predetermined pressure-volume flow characteristic curve 7).

[0096] The hydraulic circuit 1 is arranged in a housing 30 designed as a block, which has a central bore 37 in which the movable control element 9 is arranged as a movable piston and can close and open the main throttle cross-section 4 through which flow passes for the main flow path 22. The inlet connection 2 and the outlet connection 3 are each designed with bores that meet the central bore. The main throttle cross-section 4 through which flow passes is arranged between an inlet of the inlet connection 2 and an inlet of the outlet connection 3 in the central bore 37. The control chamber 5 is located within the central bore 37 to the right of the movable control element 9. The first active surface 11 connected to the inlet connection 2, the second active surface 12 adjacent to the control chamber 5 and the differential surface 19 connected to the outlet connection 3 are each marked in Fig. 12 and shown in Fig.13 is, of course, identically designed. The arrangement of the first effective surface 11, the second effective surface 12, and the differential surface 19 corresponds to the embodiment shown in Fig. 2, Fig. 6, or Fig. 8.

[0097] The movable control element 9 is designed as a hollow piston with an interior space 39 within which a pilot control piston 29 is located. The movable control element 9 has through holes 38 which connect the inlet connection 2 adjacent to the outside of the movable control element 9 with the interior space 39 and thus form an inlet 17 into the bypass line 6 or the bypass flow path 23. The throttle control 8 is formed within the interior space 39 between the movable control element 9 and the pilot control piston 29 in the form of a notch 16 on the pilot control piston 29. By displacing the movable control element 9 relative to the pilot control piston 29, a larger or smaller cross section of the notch 16 and thus of the throttle control 8 is released, through which hydraulic fluid can flow from the inlet connection 2 into the control chamber 5.

[0098] The throttle element with a predetermined pressure-volume flow characteristic 7 is designed as a spring-loaded throttle and is located within the pilot piston 29. The control valve 10 for specifying an operating point 27 of the hydraulic circuit 1 is located between the movable control element 9 and the pilot piston 29.

[0099] The pilot control piston 29 and thus the control valve 10 can be moved by a controller 20, which can be controlled by a control module 21 not shown in detail here. The control module 21 or the controller 20 are designed to move the pilot control piston 29 against the pilot control piston spring 28 into a specific position, which specifies the opening width of the main throttle cross-section 4 of the main flow path 22 for a given pressure difference between the inlet connection 2 and the outlet connection 3. Due to the forces resulting from the pressures acting on the active surfaces 11, 12 and the differential area 19, the position of the movable control element 9 is then adjusted, starting from this position of the pilot control piston 29, depending on the pressure at the inlet connection 2 and the outlet connection 3, as if the movable control element 9 were subjected to a very large mechanical spring on the control chamber 5 side.The properties of the throttle element with a predetermined pressure-volume flow characteristic curve 7 or the yielding behavior of the hydraulic circuit 1 described here when the pressure difference between the inlet connection 2 and the outlet connection 3 increases is not influenced by the opening width of the flow-through main throttle cross-section 4 because the throttle element with a predetermined pressure-volume flow characteristic curve 7 is formed between the pilot control piston 29 and the movable control element 9 with the notch 16 and the movable control element 8 follows the pilot control piston 29 when the pilot control piston 29 is displaced, so that the properties of the throttle element with a predetermined pressure-volume flow characteristic curve 7 remain the same regardless of the opening width of the flow-through main throttle cross-section 4. The control valve 10 is also formed between the pilot control piston 29 and the movable control element 9.Because the movable control element 9 follows the pilot control piston 29, the control valve 10 also adapts. The hydraulic components in the bypass line 6 (the control valve 10 and the control element 9) and their characteristic curves remain the same regardless of the position of the pilot control piston 29 when the movable control element 9 has followed the pilot control piston 29. The throttle element with the predetermined pressure-volume flow characteristic curve 7 is designed as a spring-loaded throttle within the pilot control piston 29. Its hydraulic properties are therefore unaffected by the position of the pilot control piston 29. The pressure-dependent yielding behavior of the hydraulic circuit 1 also remains the same, regardless of how far the main throttle cross-section 4 is open. Before the movable control element 9 has followed the pilot control piston 29, there is a displacement of the pilot control piston 29 relative to the movable control element 9.This displacement creates (temporarily) expanded or reduced cross-sections of the control valve 10 and the throttle element with a predetermined pressure-volume flow characteristic curve 7. This displacement can temporarily result in different volume flows of the hydraulic fluid through the first section 13 and the second section 14 of the bypass line 6, which cause an adjustment of the filling quantity of the control chamber 5. Correspondingly different volume flows of the hydraulic fluid through the first section 13 and the second section 14 also occur when the pressure difference between the inlet port 2 and the outlet port 3 changes.

[0100] Fig. 13 shows, by way of example, a preload element 15, which preloads the movable control element 9 toward a closed position of the flow-through main throttle cross-section 4. A spring would also have to be arranged accordingly, which, as a replacement for the hydraulic circuit 1 described here, could achieve the necessary forces for a pressure-dependent yielding behavior of the movable control element 9. However, such a spring would have to be very large to be able to generate sufficient spring forces. The hydraulic circuit 1 described here makes it possible to achieve the desired yielding behavior with a significantly more compact design.

[0101] List of reference symbols

[0102] 1 hydraulic circuit

[0103] 2 inlet connection

[0104] 3 Outlet connection

[0105] 4 flow-through main throttle cross-section

[0106] 5 Control chamber

[0107] 6 Bypass line

[0108] 7 Throttle element with specified pressure-volume flow characteristic

[0109] 8 Throttle control

[0110] 9 Control

[0111] 10 Control valve

[0112] 11 first effective area

[0113] 12 second effective area

[0114] 13 first section

[0115] 14 second section

[0116] 15 Preload element

[0117] 16 notch

[0118] 17 Entrance

[0119] 18 Active coupling

[0120] 19 Differential area

[0121] 20 Control

[0122] 21 Control module

[0123] 22 Main flow path

[0124] 23 Bypass flow path

[0125] 24 Bypass volume flow

[0126] 25 Pressure-volume flow characteristic of the throttle control

[0127] 26 Pressure-volume flow characteristic of the throttle element

[0128] 27 operating point

[0129] 28 Pilot piston spring

[0130] 29 pilot pistons

[0131] 30 housings

[0132] 31 connection

[0133] 32 Closing element 33 Extension

[0134] 34 through hole

[0135] 35 Control connection

[0136] 36 Feedback 37 Central hole

[0137] 38 through holes

[0138] 39 Interior

[0139] 40 Flow control valve

Claims

Drafting of patent claims 1. Hydraulic circuit (1) with an inlet connection (2) and an outlet connection (3) configured to throttle a flow of hydraulic fluid from the inlet connection (2) to the outlet connection (3) with a movable control element (9) with which a flow-through main throttle cross-section (4) between the inlet connection (2) and the outlet connection (3) can be released and which is at least partially floatingly mounted between the inlet connection (2) and a control chamber (5), wherein a bypass line (6) for hydraulic fluid exists from the inlet connection (2) to the outlet connection (3),to which the control chamber (5) is connected and in which a throttle element with a predetermined pressure-volume flow characteristic (7) and a throttle control (8) operatively coupled to the movable control element (9) are arranged in series and are designed to adapt a bypass flow through the bypass line (6), a pressure in the control chamber (5), a position of the control element (9) and / or the size of the main throttle cross-section (4) in the event of an increase in the pressure difference between the inlet connection (2) and the outlet connection (3) such that a new equilibrium position of the movable control element (9) is established and the main throttle cross-section (4) through which the flow can pass is adapted as a function of the pressure difference.

2. Hydraulic circuit (1) according to claim 1, wherein a first effective area (11) of the movable control element (9) for a pressure in the inflow connection (2) is smaller than a second effective area (12) for a pressure in the control chamber (5).

3. Hydraulic circuit (1) according to claim 2, wherein a differential area (19) which corresponds to a difference between the second effective area (12) and the first effective area (11), is connected to the outlet connection (3).

4. Hydraulic circuit (1) according to one of the preceding claims, wherein the throttle element with a predetermined pressure-volume flow characteristic (7) is designed as a spring-loaded check valve.

5. Hydraulic circuit (1) according to one of the preceding claims, wherein the bypass line (6) has a first section (13) from the inflow connection (2) to the control chamber (5) and a second section (14) from the control chamber (5) to the outflow connection (3), wherein the throttle control (8) is arranged in the first section (13) and the throttle element with a predetermined pressure-volume flow characteristic curve (7) is arranged in the second section (14).

6. Hydraulic circuit (1) according to one of the preceding claims, wherein a pressure-volume flow characteristic curve (26) of the throttle element with a predetermined pressure-volume flow characteristic curve (7) has a proportional course, so that a pressure loss occurring at the throttle element with a predetermined pressure-volume flow characteristic curve (7) increases proportionally with an increasing volume flow of hydraulic fluid through the bypass line (6).

7. Hydraulic circuit (1) according to one of the preceding claims, wherein a pressure-volume flow characteristic curve of the throttle control (25) has a disproportionate course, so that a pressure loss occurring at the throttle control (8) increases disproportionately with an increasing volume flow of hydraulic fluid through the bypass line (6).

8. Hydraulic circuit (1) according to claim 6 and 7, wherein due to a given pressure difference between the inflow connection (2) and the outflow connection (3) a position of the movable control element (9) is established, in which a bypass volume flow (24) through a first section (13) of the bypass line (6) and a bypass volume flow (24) through a second section (14) of the bypass line (6) are the same and the throttle element with a predetermined pressure-volume flow characteristic curve (7) is predetermined by the pressure-volume flow characteristic curve (26) and the resulting position of the movable control element (9) is predetermined by the pressure-volume flow characteristic curve (25) of the throttle control (8) such that the flow-through throttle cross-section (4) is dependent on the pressure-volume flow characteristic curve (26) of the throttle element with a predetermined pressure-volume flow characteristic curve (7).

9. Hydraulic circuit (1) according to one of the preceding claims, wherein the throttle control (8) is designed with a notch (16) which interacts with the control element (9) in such a way that when the flow-through main throttle cross-section (4) is adjusted, an adjustment of a bypass cross-section of the throttle control (8) occurs simultaneously.

10. Hydraulic circuit (1) according to claim 9, wherein the notch (16) is arranged on the control element (9) or on a further component (29, 30), wherein the control element (9) and the further component (29, 30) together are designed to also adapt a bypass cross-section of the bypass line (6) when adapting the main throttle cross-section (4) through which flow can occur.

11. Hydraulic circuit (1) according to one of the preceding claims, wherein a pressure-volume flow characteristic curve (25) of the throttle control (8) has a disproportionate behavior at a predetermined position of the control element (9), so that a pressure loss occurring at the throttle control (8) increases disproportionately with an increasing volume flow of hydraulic fluid through the bypass line (6).

12. Hydraulic circuit (1) according to one of the preceding claims, comprising a pilot piston (29) which can be positioned by a control (20) in order to determine an operating point (27) of the hydraulic Circuit (1) which specifies an opening width of the main throttle cross-section (4) for a given pressure difference between the inlet connection (2) and the outlet connection (3).

13. Hydraulic circuit (1) according to one of the preceding claims, wherein a control valve (10) is arranged in a second section (14) of the bypass line (6) between the control chamber (5) and the outlet connection (3), with which a flow-through cross-section can be set and an operating point (27) of the hydraulic circuit (1) can be specified.

14. Hydraulic circuit (1) according to one of the preceding claims, wherein the hydraulic circuit (1) is designed such that when the pressure at the outlet connection (3) exceeds the pressure at the inlet connection (2), the movable control element (9) is movable such that a flowable main throttle cross-section (4) is released and a flow of the hydraulic fluid from the outlet connection (3) to the inlet connection (2) is permitted.

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