Hydraulic circuit for providing a spring characteristic

Abstract

The invention relates to a hydraulic circuit (1) for generating a force that varies with stroke, having a hydraulic working chamber (2) that can be pressurized with hydraulic fluid in order to exert a force on a working piston (3), wherein the working piston (3) has a second active face (4) at which the pressure acting in the hydraulic working chamber (2) acts on the working piston (3), an output element (5) being fastened to the working piston (3), by means of which the force generated by the hydraulic fluid in the working chamber (2) can be provided as a force that varies with stroke, the hydraulic working chamber (2) having at least one inflow opening (7) and at least one outflow opening (8), a working flow of hydraulic fluid being able to flow into the working chamber (2) via the inflow opening (7) and a working flow of hydraulic fluid being able to flow out of the working chamber (2) via the outflow opening, wherein the flow resistance of the outflow opening (8) and / or the flow resistance of the inflow opening (7) is controlled as a function of the position of the working piston (3) in such a way that the pressure built up in the hydraulic working chamber (2) is controlled in a manner that varies with stroke as a function of the position of the working piston (3), so that the pressure rises as the working chamber (2) is reduced.

Description

Technical Field

[0001] This invention relates to a novel hydraulic circuit capable of providing elastic properties. In particular, this circuit eliminates the need for very large mechanical springs used to generate large forces, and replaces such springs with the hydraulic circuit described herein. Background Technology

[0002] In many applications of hydraulic technology, very strong (and therefore large) springs are required to provide the necessary spring force and spring travel. Such applications include, for example, actuators for adjustable throttle valves. These actuators typically require a relatively large actuation stroke, as well as very large actuation force. The size and weight of such springs are generally considered disadvantages. Summary of the Invention

[0003] The object of this invention is to at least partially solve the problems described with reference to the prior art. In particular, a special novel hydraulic circuit is proposed that eliminates the need for very large springs in many situations and applications.

[0004] This objective is achieved by the invention according to the features of the independent claims. Other advantageous improvements are described in the claims set forth in the dependent claims and in the description of the specification, and especially in the description of the drawings. It should be noted that those skilled in the art will combine the various features in a technically meaningful manner, thereby obtaining other improvements to the invention.

[0005] This document aims to describe a hydraulic circuit for generating a stroke-varying reaction force, the hydraulic circuit having a hydraulic working chamber capable of pressurizing the hydraulic working chamber with hydraulic fluid to apply force to a working piston, wherein the working piston has a second effective surface, the pressure acting in the hydraulic working chamber acts on the working piston at the second effective surface, and wherein an output element is fastened to the working piston and is capable of providing the force generated by the hydraulic fluid in the working chamber as a stroke-varying reaction force, wherein the hydraulic working chamber has at least one inlet opening and at least one outlet opening, and wherein the working flow of hydraulic fluid can flow into the working chamber through the inlet opening and the working flow of hydraulic fluid can flow out of the working chamber through the outlet opening, wherein the flow resistance of the outlet opening and / or the flow resistance of the inlet opening are adjusted according to the position of the working piston, such that the pressure established in the hydraulic working chamber is adjusted in a stroke-varying manner according to the position of the working piston, thereby increasing the pressure as the size of the working chamber decreases.

[0006] The hydraulic circuit described herein is intended to generate a stroke-varying reaction force that can be used in a variety of applications. Possible applications include hydraulic actuators, in which springs are typically used, and these springs can be replaced by the hydraulic circuit described herein.

[0007] For example, conventional mechanical springs (e.g., torsion springs) generate a reaction force that varies with stroke, where the spring has a spring characteristic curve describing the relationship between the stroke through which the spring is compressed or stretched / opened and the spring force generated by the spring. For conventional springs (e.g., for the torsion spring mentioned above), this relationship is linear. This means that, starting from the relaxed state of the spring, the spring force gradually increases linearly as the spring is compressed or stretched / opened. The hydraulic circuits described herein can be used to simulate or replace springs with such linear spring characteristic curves, in particular. In this case, the hydraulic circuits described herein are especially suitable for replacing springs that are compressed in their application. For springs used in a manner capable of withstanding both tensile and compressive loads, the characteristics cannot be simulated using the hydraulic circuits described herein. This would require an arrangement of multiple circuits described herein interacting, and / or an arrangement of other devices (e.g., mechanical devices) that can convert pulling motion into pushing motion. Such devices could be, for example, levers, steering mechanisms, or other devices.

[0008] The output element is, for example, a mechanical element connected to the working piston via a rod, which can output a spring-like force generated by the hydraulic circuit, or provide the force for the intended application.

[0009] The hydraulic fluid used to operate the circuit described herein is preferably substantially incompressible. The hydraulic device described herein is driven by the working flow of hydraulic fluid. The working flow of hydraulic fluid enters the working chamber through an inlet opening and exits the working chamber again through an outlet opening. The volume of the working chamber can change by displacing or changing the position of the working piston. Therefore, different volumetric flow rates may temporarily occur at the inlet and outlet openings. When the working piston is in a fixed position, the working flow of hydraulic fluid through the inlet and outlet openings is the same.

[0010] The working flow of hydraulic fluid necessary to operate the hydraulic circuit described herein is preferably provided by a hydraulic fluid source connected to the inlet opening. The working flow exiting the outlet opening is preferably discharged via a tank opening into a reservoir for "used" hydraulic fluid. The hydraulic fluid is preferably pumped from such a reservoir and pressurized by a hydraulic pump to supply the hydraulic circuit described herein (and possibly other hydraulic circuits in a larger system). For example, such a hydraulic pump can form a hydraulic fluid source. In other variant embodiments, the working flow may also be supplied to a throttled hydraulic fluid flow. The hydraulic circuit described herein functions as a hydraulic throttle for the working flow itself.

[0011] The hydraulic working chamber is preferably disposed within a housing, which is particularly cylindrical. A working piston is movably mounted within the housing. The housing preferably provides a cylinder chamber in which the working piston is movably mounted. Therefore, the working chamber is preferably formed by a portion of the cylinder chamber defined by the working piston. The working chamber can be enlarged or reduced in size by movement of the working piston. The working chamber is defined, in particular, by the housing and the working piston. A second effective surface on the working piston preferably forms the wall / boundary of the working chamber. Other walls / boundaries of the working chamber are preferably formed by the housing. The term "second effective surface" is used herein with the ordinal number "two" because in preferred embodiments of the hydraulic circuit described herein, the working piston also has an additional first effective surface arranged on the side of the working piston opposite to the second effective surface. In these variant embodiments, which will be described in more detail below, the working flow preferably flows first through the first effective surface and then through the second effective surface. However, a first effective surface is not required in all variant embodiments of the hydraulic circuit described herein. Therefore, the ordinal number "two" does not imply that a first effective surface must also be present. Functionally, the second effective surface can also be referred to as the effective surface at the working cavity, or as the effective surface subjected to the force of the hydraulic spring.

[0012] The inlet and / or outlet openings are designed such that their flow resistance to the hydraulic fluid flowing through them, or particularly their cross-sectional area through which the fluid can flow, varies depending on the position of the working piston. Particularly preferably, the inlet or outlet opening is arranged on the housing forming the working chamber, or within / on the cylinder cavity, such that the working piston is located near the opening (inlet or outlet opening) during operation of the hydraulic device. Particularly preferably, the working piston sweeps across the inlet or outlet opening as it changes position or moves. Particularly preferably, different interactions exist with the inlet or outlet opening depending on the position of the working piston. Preferably, this interaction achieves or at least assists in achieving the influence on the working flow of the hydraulic fluid through the inlet, outlet, and working chamber.

[0013] The hydraulic circuit described herein is configured such that the working flow of hydraulic fluid increases or becomes larger when the volume of the working chamber decreases and the force provided by the hydraulic circuit increases. In particular, the working flow of hydraulic fluid is preferably smaller when the force generated by or output from the hydraulic circuit is smaller. These characteristics of the hydraulic circuit are advantageous because the loss or throttling of the supplied pressurized hydraulic fluid is smaller when the applied force is smaller. Therefore, the hydraulic circuit described herein can be used efficiently, especially when a large force is only temporarily required from the hydraulic circuit.

[0014] Particularly preferably, if a throttling control unit operably connected to the working piston is arranged at the inlet opening, and the throttling control unit is configured such that when the working piston reduces the size of the working chamber, the working flow into the working chamber increases.

[0015] In other words, when the working piston is moved and the size of the working chamber of the hydraulic circuit decreases, the throttling control unit opens further, and when the working piston is moved and the size of the working chamber of the hydraulic circuit increases, the throttling control unit closes further.

[0016] Specifically, the throttling control is configured to open an enlarged inflow cross-section at the inflow opening when the working piston is moved, reducing the size of the working chamber. In a preferred variant of this circuit, this is achieved through a groove on the working piston and a specially configured inflow opening. The inflow opening is preferably arranged on the circumferential surface of the cylinder chamber in which the working piston is movably mounted and the working chamber is disposed. The inflow opening is preferably located in the region of the circumferential surface where the working piston is located. The working piston preferably sweeps across the inflow opening when changing its position. The throttling control is particularly preferably formed by a structure formed on the working piston. Particularly preferably, the operable connection between the working piston and the throttling control is achieved by the working piston sweeping across the inflow opening when changing its position.

[0017] Preferably, if the throttling control is designed as a groove, the groove opens a variable inflow cross section into the working chamber depending on the position of the working piston.

[0018] The groove is particularly preferably formed on the working piston. More preferably, depending on the position of the working piston, the groove overlaps with the inflow opening to varying degrees or at different locations. In a preferred variant embodiment, the groove is oriented along or parallel to the direction of movement of the working piston and is elongated in shape. More preferably, the groove has different depths along the direction of movement of the working piston. More preferably, depending on the position of the working piston, the inflow opening partially overlaps with the groove at different depths. More preferably, the depth of the groove at the location where it overlaps with the inflow opening further defines the inflow cross-section into the working chamber.

[0019] Furthermore, preferably, the outflow opening is provided with a throttling element having a predetermined pressure-volume flow rate characteristic curve, which is configured such that the volume flow rate through the outflow opening increases with increasing pressure.

[0020] A throttling element with a predetermined pressure-volume flow rate characteristic curve predetermines the pressure loss of the hydraulic fluid as it flows out of the working chamber. The greater the volumetric flow rate of the hydraulic fluid flowing into the working chamber through the inlet opening and the throttling control section, the more hydraulic fluid must flow out of the working chamber through the outlet opening and the throttling element.

[0021] Therefore, the predetermined pressure-volume flow characteristic curve of the throttling element further increases the pressure in the working chamber. This necessitates the application of a greater force to hold the working piston in a specific position. This is achieved using the spring force or spring-like force generated by the hydraulic circuit described in this paper.

[0022] In this case, the throttling control unit is particularly preferably designed to have a pressure-volume flow rate characteristic curve in which the pressure loss increases proportionally with increasing volumetric flow rate, at a given opening width or at a given position of the working piston. This is preferably applied to every position of the working piston, wherein the pressure-volume flow rate characteristic curve is preferably compressed and / or shifted by the displacement of the working piston and the volume change of the working chamber. A decrease in the size of the working chamber and a corresponding change in the position of the working piston preferably causes the pressure-volume flow rate characteristic curve of the throttling control unit to decrease / compress. An increase in the size of the working chamber and a corresponding change in the position of the working piston preferably causes the pressure-volume flow rate characteristic curve of the throttling control unit to increase / stretch.

[0023] The interaction between the pressure-volume flow rate characteristic curve of the throttling element and the pressure-volume flow rate characteristic curve of the throttling control unit, and the dependence of the pressure-volume flow rate characteristic curve of the throttling control unit on the volume of the working chamber and the position of the working piston, preferably produces a dependence of the pressure in the working chamber on the volume of the working chamber and the position of the working piston, thereby producing a spring force or spring-like force at the output element of the hydraulic circuit described herein.

[0024] Preferably, the throttling element at the outlet opening is a spring-loaded check valve.

[0025] The spring characteristic curve of the check valve spring is preferably predefined by the pressure-volume flow characteristic curve of the throttling element. In particular, the hydraulic circuit described herein amplifies the spring characteristic curve of the check valve spring of the throttling element in such a way that the characteristic curve of the spring force or spring-like force induced at the output element by the circuit described herein varies with stroke and is proportional to the spring characteristic curve of the check valve spring.

[0026] In a preferred embodiment, the hydraulic circuit has a hydraulic control chamber that can be pressurized by hydraulic fluid, and the hydraulic control chamber is arranged on the side opposite to the working piston at the working piston. The working piston has a first effective surface, and the pressure acting on the hydraulic control chamber acts on the working piston at the first effective surface, opposite to the pressure acting on the working chamber. The control chamber can be connected to a control pressure source, and the inflow opening of the working chamber is connected to the control chamber, so that the hydraulic fluid flowing out of the control chamber flows into the working chamber.

[0027] The control chamber is particularly preferably formed within the housing, in which the working chamber of the circuit described herein is also arranged. The housing preferably provides a cylinder chamber in which a working piston is movably mounted, wherein the working piston separates the working chamber from the control chamber. Preferably, the pressure present in the control chamber acts on the working piston in the opposite direction to the pressure in the working chamber. The control chamber and the working chamber are preferably connected in series hydraulically. Thus, the control pressure source for providing hydraulic fluid to pressurize the control chamber preferably also serves as a hydraulic fluid source for operating the hydraulic circuit formed via the working chamber to simulate elastic properties.

[0028] A throttling control section is preferably formed between the control chamber and the working chamber. The inflow cross-section of the throttling control section predefines the contact resistance of the hydraulic fluid flowing from the control chamber into the working chamber. The inflow cross-section preferably increases as the pressure in the control chamber increases. This is preferably achieved by the displacement of the working piston, which opens up a larger inflow cross-section.

[0029] If hydraulic fluid from the control pressure source is used to pressurize the control chamber to a greater extent, the working piston will be displaced. As the flow resistance of the throttling control unit decreases, and because a throttling element is arranged at the outlet opening of the working chamber, the pressure in the working chamber subsequently increases, and a force balance is established. This force balance places the working piston in a definite position, thereby also placing the output element attached to the working piston in a definite position.

[0030] The structure described in this paper provides a specific possibility for designing a compact actuator with a hydraulic spring, which is suitable for generating very large actuating force within a compact structural volume. In this case, the structure behaves as if it had a very large / strong mechanical spring arranged inside.

[0031] Preferably, if the pressure acting in the working chamber acts on the working piston at the second effective surface, and the pressure acting in the control chamber acts on the working piston at the first effective surface, and the second effective surface is greater than the first effective surface.

[0032] Preferably, if the differential surface located on one side of the first effective surface of the working piston is connected to the outflow opening of the working chamber, the first effective surface is smaller than the differential surface than the second effective surface.

[0033] Because of the structure that positions the working chamber downstream of the control chamber along the flow direction of the hydraulic fluid, the pressure in the working chamber is always lower than the pressure in the control chamber (under any steady-state operating conditions). To still ensure the force balance required for the intended operation of the hydraulic circuit at the working piston, the second effective surface is preferably larger than the first effective surface. The effective surfaces (first effective surface, second effective surface, and / or differential surface) can also be further reduced or increased by an output element or by a rod that connects the output element to the working piston and extends out of the housing (or out of the cylinder chamber housed within the housing and accommodating the working piston).

[0034] Furthermore, the hydraulic circuit preferably has a tank pressure chamber adjacent to the differential surface, wherein at least one outflow opening of the working chamber is connected to the tank pressure chamber, so that the hydraulic fluid flowing out of the working chamber flows into the tank pressure chamber, wherein the tank pressure chamber also has a tank opening at which hydraulic fluid can be discharged from the tank pressure chamber.

[0035] The oil tank pressure chamber is preferably also located within the housing or within a cylinder chamber provided by the housing. The oil tank pressure chamber is preferably separated from the control chamber by an extension formed on the working piston. The cylinder chamber or housing preferably has a tapered section into which the extension on the working piston extends. The oil tank pressure chamber is particularly preferably formed within this tapered section of the cylinder chamber or housing. During operation of the hydraulic circuit, the pressure applied to the differential surface in the oil tank pressure chamber is preferably significantly lower than the pressure in the working chamber.

[0036] In a preferred variant embodiment, the outflow opening and the throttling element are hydraulically arranged between the working chamber and the oil tank pressure chamber, so that the hydraulic fluid leaving the working chamber and the outflow opening enters the oil tank pressure chamber.

[0037] Furthermore, preferably, the outflow opening is designed as a connecting pipe in the working piston.

[0038] This allows for a particularly compact design of the hydraulic circuit. In other variant embodiments, the throttling element can also be arranged outside the working piston, for example, within a housing that also provides a cylinder chamber in which the working piston is housed. Attached Figure Description

[0039] The invention and its technical environment are described in more detail below with reference to the accompanying drawings. The drawings illustrate preferred exemplary embodiments, but the invention is not limited to these exemplary embodiments. It should be particularly noted that the drawings, and especially the dimensions shown in the drawings, are merely schematic. In the drawings:

[0040] Figure 1 A mechanical device for generating a reaction force that varies with the stroke is shown;

[0041] Figure 2A mechanical device for generating manipulated variables based on control pressure is shown;

[0042] Figure 3 A variant embodiment of a hydraulic circuit for generating a reaction force that varies with stroke is shown;

[0043] Figure 4 Another variant embodiment of the hydraulic circuit for generating a reaction force that varies with stroke is shown;

[0044] Figure 5 A hydraulic circuit for generating manipulated variables in response to control pressure is shown; and

[0045] Figure 6 Another variant embodiment of a hydraulic circuit for generating manipulated variables based on control pressure is shown. Detailed Implementation

[0046] Figure 1 A mechanical device is shown in which a spring 14 generates a reaction force that varies with stroke. The spring force of spring 14 is provided at the output element 5. Spring 14 is clamped between plunger 22 and housing 23. Output element 5 is mechanically connected to plunger 22 via rod 6, and thus mechanically connected to spring 14, such that the spring force of spring 14 acts on output element 5. Depending on the force F acting on output element 5, spring 14 is compressed to different degrees. The spring characteristic curve of spring 14 provides the relationship between the position of output element 5 and the force acting on output element 5; for a conventional spring 14, this relationship is linear.

[0047] Figure 2 A mechanical device is shown for generating manipulated variables based on control pressure provided by control pressure source 19. Figure 2 The device with Figure 1The device is constructed based on this. Here, spring 14 is also braced between housing 23 and plunger 22. Furthermore, a control chamber 17 is provided, to which pressure from control pressure source 19 can act. The pressure in control chamber 17 acts on a first effective surface 18 on plunger 22, which is located on the side opposite to spring 14. Therefore, the pressure in control chamber 17 acts in the opposite direction to the spring force of spring 14. Under no-load conditions where the force F on output element 5 is 0 Newtons, the pressure in control chamber 17 and the spring characteristic curve of spring 14 allow the position of output element 5 to be set. Under load conditions where the force F on output element 5 is less than or equal to 0 Newtons, the volume of hydraulic fluid in control chamber 17 predetermines the position of output element 5. Depending on the magnitude of the force F on output element 5, a corresponding pressure is required in control chamber 17 to maintain the determined position of output element 5. Depending on the position of output element 5, spring 14 is compressed to different degrees. The greater the compression of spring 14, the greater its spring force. Therefore, the pressure required in the control chamber 17 to maintain the output element 5 in a specific position also depends on the spring force of the spring 14. The spring force of the spring 14 is superimposed on the force F acting on the output element 5.

[0048] Figure 3 and Figure 4 This paper illustrates the principle described herein, which enables the simulation of hydraulically based... Figure 1 The characteristics of spring 14 in the device. In this case, according to Figure 3 and Figure 4 Hydraulic circuit 1 can be used to generate very large forces, utilizing... Figure 1 Generating these forces using a purely mechanical structure would require a very large spring 14. Therefore, according to... Figure 3 and Figure 4 The hydraulic circuit 1 requires a continuous inflow of pressurized hydraulic fluid from the hydraulic fluid source 24, which is discharged into a reservoir (referred to herein as tank opening 16). However, this is perfectly acceptable for a variety of applications.

[0049] according to Figure 3 and Figure 4 Each hydraulic circuit 1 has a working piston 3, which is guided within a housing 23 and defines a working chamber 2 within the housing 23. During operation of the hydraulic circuit 1, the working chamber 2 is filled with hydraulic fluid. The working piston 3 forms a second effective surface 4, on which the hydraulic fluid in the working chamber 2 is pressed. The pressure of the hydraulic fluid in the working chamber 2 on the effective surface 4 corresponds to the pressure of the hydraulic fluid in the working chamber 2. Figure 1 The spring force of spring 14 in the mechanical device.

[0050] according to Figure 3 and Figure 4The hydraulic circuit 1 is configured such that the pressure of the hydraulic fluid in the working chamber 2 increases as the working piston 3 moves further downward. This corresponds to the characteristics provided by the spring 14 arranged in the working chamber 2, or on the second effective surface 4 on one side of the working chamber 2 at the working piston 3. The greater the compression of such spring 14, the stronger the spring force generated. Therefore, the hydraulic circuit 1 is configured such that the pressure in the working chamber 2 increases as the size of the working chamber 2 decreases.

[0051] The corresponding performance is achieved as follows: a continuous flow of hydraulic fluid flows from the hydraulic fluid source 24 into the working chamber 2 via the inlet opening 7, and then flows out of the working chamber 2 again via the outlet opening 8. A throttling control unit 9 is provided at the inlet opening 7, which is connected to the working piston 2, such that when the working piston 3 moves and the size of the working chamber 2 decreases, the inlet cross-section 11 of the inlet opening 7 increases. Therefore, the decrease in the size of the working chamber 2 increases the amount of hydraulic fluid flowing into the working chamber 2.

[0052] Figure 3 The diagram illustrates how such a throttling control unit 9 can be specifically implemented. The inflow opening 7 is arranged such that it is at least partially covered by the working piston 3. A groove 10 is arranged in the working piston 3, which connects to the working chamber 2 via a connecting channel 25, and opens an inflow cross-section 11 of varying sizes to the working chamber 2 depending on the position of the working piston 3. The lower the working piston 3 is, or the smaller the working chamber 2 is, the larger the opened inflow cross-section 11, and the more hydraulic fluid can flow into the working chamber 2 through the inflow opening 7.

[0053] Figure 4 The principle is illustrated more generally. Here, the operable connection 26 between the working piston 3 and the throttling control unit 9 is shown in dashed lines. This operable connection 26 is designed such that downward movement of the working piston 3 or a decrease in the size of the working chamber 2 increases the inflow cross-section 11.

[0054] A throttling element 12 is provided at the outlet opening 8, according to Figure 3 and Figure 4 In both variant embodiments, the throttling element is designed as a spring-loaded check valve 13. The greater the pressure in the working chamber 2 or at the outlet opening 8, the wider the throttling element 12 opens, and the more hydraulic fluid flows from the working chamber 2 into the tank opening 16 via the outlet opening 8. In this way, the throttling element 12 at the outlet opening 8 controls the pressure in the working chamber 2 and ensures that the pressure in the working chamber 2 increases as the volumetric flow rate of the hydraulic fluid passing through the working chamber 2 increases. Therefore, by means of the throttling control unit 9 and the throttling element 12, the volumetric flow rate of the hydraulic fluid is predetermined based on the position of the working piston 3, thereby establishing pressure in the working chamber 2 by means of the throttling element 12.

[0055] Figure 4 It is also shown that the inflow opening 7 and the outflow opening 8 can also jointly lead into the working chamber 2. Importantly, the interaction between the throttling control unit 9 at the inflow opening 7 and the throttling element 12 at the outflow opening 8 establishes the dependence of the pressure of the hydraulic fluid in the working chamber 2 on the position of the working piston 3. This pressure can also be transmitted to the working chamber 2 from the inflow opening 7 and the outflow opening 8 via the common inlet passage 27.

[0056] Figure 5 and Figure 6 A hydraulic circuit 1 is shown for generating manipulated variables based on the control pressure provided by the control pressure source 19. According to... Figure 5 and Figure 6 Hydraulic circuit 1 according to Figure 3 and Figure 4 It is constructed based on hydraulic circuit 1.

[0057] In terms of its operation, according to the device Figure 5 and Figure 6 Hydraulic circuit 1 in the middle provides and according to Figure 2 The corresponding functions of the mechanical / hydraulic devices.

[0058] In this case, according to Figure 5 and Figure 6 The hydraulic circuit 1 can be used to generate very large control forces, and by utilizing... Figure 2 The mechanical / hydraulic structure that generates these control forces will require very large springs 14. Therefore, according to... Figure 5 and Figure 6 The hydraulic circuit 1 requires a continuous inflow of pressurized hydraulic fluid from the hydraulic fluid source 24, which is discharged into a reservoir (here referred to as tank opening 16). In this respect, according to Figure 5 and Figure 6 Hydraulic circuit 1 according to Figure 3 and Figure 4 The hydraulic circuit 1 is designed or conceptualized based on these circuits.

[0059] The requirement for a continuous inflow of pressurized hydraulic fluid is perfectly acceptable, especially for Figure 5 and Figure 6 These hydraulic circuits 1. This is especially true because a control pressure source 19 for providing control pressure can be combined with a hydraulic fluid source 24 for providing a continuous flow of hydraulic fluid to operate the hydraulic circuit 1 and provide the resilient properties of the hydraulic circuit 1.

[0060] Figure 5 and Figure 6 Each of the hydraulic circuits 1 has a control chamber 17, which corresponds to Figure 2The control chamber 17 of the device. The control chamber 17 is located within the housing 23 in which the working piston 3 is arranged, such that the control chamber 17 is defined by a first effective surface 18 formed on the working piston 3, and such that the pressure of the hydraulic fluid present in the control chamber 17 acts on the working piston 3 at the first effective surface 18. This corresponds to Figure 2 The situation.

[0061] On the other side, the working piston 3 has a second effective surface 4 defining the working chamber 2. This working chamber 2 is also arranged within the housing 23. In other words, the working piston 3 divides the space within the housing 23 available for hydraulic fluid to occupy into the working chamber 2 and the control chamber 17. By displacing the working piston 3, the size of the control chamber 17 increases while the size of the working chamber 2 decreases, or vice versa. The output element 5 is fastened to the working piston 3 by a rod 6, by means of which the hydraulic circuit 1 described herein can be configured according to… Figure 2 The device is used to control the task.

[0062] According to Figure 5 and Figure 6 In hydraulic circuit 1, the control pressure source 19 and the hydraulic fluid source 24 are already connected. When using... Figure 5 and Figure 6 When hydraulic circuit 1 is in operation, hydraulic fluid continuously flows from hydraulic fluid source 24 or control pressure source 19 to oil tank opening 16, which results in... Figure 2 This will not occur in such devices. However, for many applications, such a continuous outflow of hydraulic fluid is acceptable, or even desirable, because in any case the pressure of the hydraulic fluid flow must be throttled, and the hydraulic fluid flow must be utilized to operate according to... Figure 5 and Figure 6 Hydraulic circuit 1.

[0063] According to Figure 5 and Figure 6 In the hydraulic circuit 1, along the flow direction of hydraulic fluid from hydraulic fluid source 24 or control pressure source 19 to tank opening 16, control chamber 17 is arranged upstream of working chamber 2. An inflow opening 7 leading into working chamber 2 is formed between control chamber 17 and working chamber 2. The throttling control part 9 at inflow opening 7 is specifically designed as a groove 10 on the working piston 3, such that the farther the working piston 3 moves towards working chamber 2, or the smaller the working chamber 2, the greater the amount of hydraulic fluid entering working chamber 2 from the inflow cross section 11 or from control chamber 17. Figure 3 and Figure 4 Similar to the hydraulic circuit 1, the outflow opening 8 is equipped with a throttling element 12 designed as a spring-loaded check valve 13.

[0064] according to Figure 5 and Figure 6In two variant embodiments, the second effective surface 4 of the working piston 3 oriented toward the working chamber 2 is larger than the first effective surface 18 of the working piston 3 oriented toward the control chamber 17. When hydraulic fluid flows through the inlet opening 7, or when hydraulic fluid enters the working chamber 2 from the control chamber 17, the throttling control unit 9 causes a pressure loss in the hydraulic fluid. Given this fact, the second effective surface 4 must be larger than the first effective surface 18; otherwise, the pressure acting on the first effective surface 18 would generate a greater force than the pressure acting on the second effective surface 4, and the elastic properties of the hydraulic circuit 1 would be impaired. For this reason, the hydraulic circuit 1 also has a tank pressure chamber 21, which is defined by a differential surface 20 formed on the working piston 3. The differential surface 20 corresponds to the surface difference between the first effective surface 18 and the second effective surface 4. The pressure at the tank opening 16 exists in the tank pressure chamber 21, which is significantly lower than the pressure in the working chamber 2. For this reason, the pressure applied to the differential surface 20 will not adversely affect the ratio of the forces acting on the working piston 3, which is necessary for the elastic characteristics of the hydraulic circuit 1, or will not adversely affect the ratio in a disruptive manner.

[0065] exist Figure 5 In a modified embodiment, the throttling element 12 is integrated into the working piston 3. For this purpose, a connecting pipe 15 is formed in the working piston 3, connecting the working chamber 2 to the oil tank pressure chamber 21, and the throttling element 12 is formed in this connecting pipe. An outlet opening 8 is formed using the connecting pipe 15. Figure 6 In a variant embodiment, the throttling element 12 is arranged outside the working piston 3 (e.g., inside the housing 23).

[0066] List of reference numerals

[0067] 1 Hydraulic circuit

[0068] 2 Working Chamber

[0069] 3 Working piston

[0070] 4 Second effective surface

[0071] 5 Output Components

[0072] 6 strokes

[0073] 7. Inflow Opening

[0074] 8. Outflow opening

[0075] 9. Throttling Control Section

[0076] 10 Grooves

[0077] 11. Inflow section

[0078] 12 Throttling elements

[0079] 13 Spring-loaded check valve

[0080] 14 Mechanical Springs

[0081] 15 Connecting pipes

[0082] 16 Fuel tank opening

[0083] 17 Control Chamber

[0084] 18 First effective surface

[0085] 19. Control the pressure source

[0086] 20 Differential Surfaces

[0087] 21 Oil tank pressure chamber

[0088] 22 plungers

[0089] 23. Shell

[0090] 24 Hydraulic fluid source

[0091] 25 Connection Channels

[0092] 26 Operable connections

[0093] 27. Entrance passage

Claims

1. A hydraulic circuit (1) for generating a reaction force that varies with stroke, having a hydraulic working chamber (2) pressurized by a hydraulic fluid to apply force to a working piston (3), wherein, The working piston (3) has a second effective surface (4), and the pressure acting on the hydraulic working chamber (2) acts on the working piston (3) at the second effective surface. An output element (5) is fastened to the working piston (3) and is capable of providing a force generated by the hydraulic fluid in the working chamber (2) as a reaction force varying with stroke. The hydraulic working chamber (2) has at least one inlet opening (7) and at least one outlet opening (8). A working flow of hydraulic fluid can flow into the working chamber (2) via the inlet opening (7), and the working flow of hydraulic fluid can flow out of the working chamber (2) via the outlet opening. The flow resistance of the outlet opening (8) and / or the flow resistance of the inlet opening (7) are adjusted according to the position of the working piston (3) so that the pressure established in the hydraulic working chamber (2) varies with stroke according to the position of the working piston (3), thereby increasing the pressure as the size of the working chamber (2) decreases.

2. The hydraulic circuit (1) according to claim 1, wherein, A throttling control unit (9) operably connected to the working piston (3) is arranged at the inflow opening (7), and the throttling control unit is configured such that when the working piston (3) reduces the size of the working chamber (2), the working flow into the working chamber (2) increases.

3. The hydraulic circuit (1) according to claim 1 or 2, wherein, The throttling control unit (9) is designed as a groove (10), which opens a variable inflow cross section (11) into the working chamber (2) according to the position of the working piston (3).

4. The hydraulic circuit (1) according to any one of the preceding claims, wherein, The outflow opening (8) is provided with a throttling element (12) having a predetermined pressure-volume flow rate characteristic curve, which is configured such that the volume flow rate through the outflow opening (8) increases with increasing pressure.

5. The hydraulic circuit (1) according to claim 4, wherein, The throttling element (12) at the outlet opening (8) is a spring-loaded check valve (13).

6. The hydraulic circuit (1) according to any one of the preceding claims, having a hydraulic control chamber (17), pressurizable by hydraulic fluid, and the hydraulic control chamber being arranged on the side of the working piston (3) opposite to the working chamber (2), wherein, The working piston (3) has a first effective surface (18), and the pressure acting on the hydraulic control chamber (17) acts on the working piston (3) at the first effective surface, opposite to the pressure acting on the working chamber (2), wherein the control chamber (17) can be connected to a control pressure source (19), and wherein the inflow opening (7) of the working chamber (2) is connected to the control chamber (17), such that the hydraulic fluid flowing out of the control chamber (17) flows into the working chamber (2).

7. The hydraulic circuit (1) according to claim 6, wherein, The pressure acting in the working chamber (2) acts on the working piston (3) at the second effective surface (4), and the pressure acting in the control chamber (17) acts on the working piston (3) at the first effective surface (18), and the second effective surface is larger than the first effective surface.

8. The hydraulic circuit (1) according to claim 7, wherein, The differential surface (20) located on one side of the first effective surface (18) of the working piston (3) is connected to the outflow opening (8) of the working chamber (2), and the first effective surface (18) is smaller than the differential surface than the second effective surface (4).

9. The hydraulic circuit (1) according to claim 8, having a tank pressure chamber (21) adjacent to the differential surface (20), wherein, The at least one outflow opening (8) of the working chamber (2) is connected to the oil tank pressure chamber (21), so that the hydraulic fluid flowing out of the working chamber (2) flows into the oil tank pressure chamber (21), wherein the oil tank pressure chamber (21) also has an oil tank opening (16) at which hydraulic fluid can be discharged from the oil tank pressure chamber (21).

10. The hydraulic circuit (1) according to any one of claims 6 to 9, wherein, The outflow opening (8) is designed as a connecting pipe (15) in the working piston (3).

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