Hydraulic fill valve assembly and hydraulic assembly having a fill valve assembly

Abstract

The invention discloses a hydraulic filling valve assembly for resuction of pressure medium into a pressure chamber of a hydraulic cylinder and for releasing pressure medium therefrom, having a valve with a continuously adjustable throughflow cross section through which pressure medium can be resucked into the pressure chamber and pressure medium can be pressure-controlled or force-controlled released from the pressure chamber. Furthermore, the invention discloses a hydraulic assembly having such a filling valve assembly.

Description

Technical Field

[0001] The present invention relates to a hydraulic filling valve assembly for re-suction, particularly for hydraulic presses, especially large presses, according to the present invention, and to a hydraulic assembly, particularly for large presses, having a filling valve assembly and a hydraulic cylinder through which a pressure medium is supplied. Background Technology

[0002] Hydraulic components, such as hydraulic presses, have press cylinders whose pistons can be discharged during free fall to quickly shut down the press. Therefore, short cycle times are feasible. Here, the pressure medium must be replenished sufficiently quickly into the press cylinder, which increases in pressure upon discharge. The pressure medium flows from a loaded pressure medium container into the pressure chamber via one or more filling valves. Immediately following this is the rapid filling or rapid stroke of the piston, which applies force, especially during the forming process. In the case of large presses, the working pressure can exceed 450 bar, currently reaching approximately 700 bar, and this working pressure is also applied to the filling valves. Following the force stroke, the pressure chamber is depressurized according to a rated variation curve, thereby controlling the reduction of the clamping force. Here, these filling valves perform the necessary task of releasing the pressure medium from the pressure chamber. To enable precise control according to the rated variation curve, conventional filling valves are designed as spool valves. This requires sufficient pressure resistance for the aforementioned pressure range, but it is costly.

[0003] Furthermore, the construction of fixed conventional filling valves on large presses is costly. Summary of the Invention

[0004] In contrast, the objective of this invention is to provide a hydraulic filling valve assembly and a hydraulic assembly incorporating the hydraulic filling valve assembly, which reduces the technical cost of the device while maintaining the same quality of filling and depressurization control.

[0005] The first task is solved by a hydraulic filling valve assembly according to the invention, and the second task is solved by a hydraulic assembly according to the invention.

[0006] Advantageous improvements to the invention are described in other parts of this disclosure.

[0007] A filling valve assembly, particularly for hydraulic components such as hydraulic presses, especially large presses with operating pressures greater than 450 bar to about 700 bar, is configured to control the re-drawing (Nachsaugen) of pressure medium into the pressure chamber of the component's hydraulic cylinder, and to control the force-controlled and / or pressure-controlled release of pressure medium from the hydraulic cylinder. For this purpose, the filling valve assembly has at least one valve having a continuously adjustable flow cross-section through which re-drawing and release can be controlled. According to the invention, the valve has a logic valve, particularly an active logic valve, which is designed and / or controlled such that the continuously adjustable flow cross-section is formed by the logic valve.

[0008] Logic valves have a simpler structure than traditional spool valves designed for re-suction, filling, and release, thus reducing costs.

[0009] In one improved embodiment, the valve has a pre-control valve associated with the logic valve, the pre-control valve being continuously adjustable and capable of continuously controlling the flow cross-section of the logic valve. The pre-control valve is preferably designed as a spool valve and / or as a proportional valve.

[0010] In one improvement, the filling valve assembly has a valve block into which a logic valve arrangement, at least in the form of a cartridge or cylindrical structure, is inserted or screwed. This reduces the fixed costs of the logic valve. Furthermore, a simple and reliable connection is achieved between the pressure chamber and the pressure medium container, particularly a low-pressure source (from which the pressure medium can be re-drawn and / or into which the pressure medium can be released), and the logic valve.

[0011] In one improved embodiment, the filling valve assembly, particularly in parallel with the logic valve mentioned above, has at least one additional logic valve that can draw the pressure medium back into the pressure chamber through the additional flow cross-section of the additional logic valve.

[0012] A filling valve assembly having at least one additional logic valve arranged in a switching configuration and at least one continuously adjustable, especially pre-controlled, logic valve is used in an advantageous manner to replace a conventional filling valve assembly.

[0013] In one improved embodiment, the logic valves are designed to have the same or different nominal values. Therefore, it is advantageous to use equivalent components or highly variable control, or combinations thereof.

[0014] In one improved scheme, the logic valve structure is the same for the same or different nominal values.

[0015] The nominal quantities can vary so much that they exist in ratios of 1:2, 1:4, 1:8, and so on. Therefore, the re-suction volume flow can be easily adjusted by selectively choosing or manipulating the logic valves to be opened and kept closed.

[0016] In one improvement, an additional logic valve, or at least one of the additional logic valves, is equipped with a pre-control valve capable of continuous adjustment as described above. Therefore, the additional logic valve in question is configured with a continuously adjustable flow cross-section, particularly as a proportional valve, which enables finer control.

[0017] Alternatively or supplementally, at least one of the additional logic valves is configured to have a switchable flow cross-section, particularly configured as a switching valve.

[0018] In one improved embodiment, at least one of the logic valves is configured as an openable check valve.

[0019] In order to enable the rapid stroke of the hydraulic cylinder, and especially to maximize the rapid and / or cavitation-free re-suction or filling of the pressure chamber of the hydraulic cylinder, it is preferable to open one or more logic valves with the full flow cross-section.

[0020] The pre-control valve of the additional logic valve can be constructed as a simple switching valve, which keeps the technical cost of the device low.

[0021] Preferably, the corresponding logic valve is a seat valve.

[0022] Preferably, the pre-control valve of the logic valve mentioned for the first time is constructed in the form of a spool valve.

[0023] Preferably, the corresponding pre-control valve is configured to be electromagnetically operable, and the pre-control valve of the logic valve mentioned first is preferably also proportionally operable to ensure continuous regulation of the logic valve mentioned first. The pre-control valve of the logic valve configured only as a switching valve is preferably configured as an electromagnetically operable switching valve.

[0024] In one improved embodiment, the pre-control valve of the logic valve mentioned for the first time has a control pressure medium chamber, which is fluidly connected, in particular, to a control pressure medium source. Furthermore, the pre-control valve has a low-pressure chamber, which is fluidly connected, in particular, to a pressure medium tank. Additionally, the pre-control valve has a first control chamber, which is fluidly connected, in particular, to a first control surface of the valve body of the logic valve mentioned for the first time, acting in the direction of decreasing flow cross-section. In this way, the logic valve can be operated towards the closed position via the pre-control valve.

[0025] In one improved embodiment, the first control chamber is fluidly connected to, and in particular to, the smaller second control surface of the valve body of the logic valve mentioned for the first time, which acts in the direction of increasing flow cross-section.

[0026] In one improved embodiment, the first control room is fluidly, particularly permanently, or fixedly connected to the first control surface and the second control surface.

[0027] In an alternative improvement, the first control chamber is fluidly separated from the particularly small second control surface of the valve body, which acts in the direction of increasing flow cross-section.

[0028] In one improved embodiment, the pre-control valve of the logic valve mentioned for the first time has a second control chamber that is fluidly connected to a second control surface of the valve body of the logic valve mentioned for the first time, which functions in the direction of increasing flow cross-section, or the second control chamber is switched to not function with respect to the flow cross-section, in particular by means of fluid separation of the second control chamber from the second control surface, in particular by means of the second control chamber being closed.

[0029] Therefore, the second control room can be configured without a pressure medium pipeline leading into the second control room or configured with a pressure medium pipeline leading into the second control room, wherein the pressure medium pipeline is shut off, for example, by a plug or valve.

[0030] In one improved embodiment, the pre-control valve of the logic valve mentioned for the first time has a second control chamber, which is fluidly connected, and in particular connected, to a second control surface of the valve body of the logic valve mentioned for the first time, acting in the direction of increasing flow cross-section. In this way, a finer adjustment of the flow cross-section is achieved by the pre-control valve against the closing force of the first control surface.

[0031] In one improved embodiment, the pre-control valve of the logic valve mentioned for the first time has a first end position in which a first control chamber is connected to a control pressure medium chamber and separated from a low-pressure chamber, and in the same first end position, a second control chamber is connected to the low-pressure chamber and separated from the control pressure medium chamber. Therefore, in the first end position, a clear correspondence is established between applying pressure medium to the first control surface at control pressure and applying low pressure to the second control surface.

[0032] In one improved embodiment, the pre-control valve has a second end position in which the first control chamber is connected to the low-pressure chamber and separated from the control pressure medium chamber, and in the second end position, the second control chamber is connected to the control pressure medium chamber and separated from the low-pressure chamber. Therefore, in the second end position, the first control surface is loaded with low pressure, and the second control surface is loaded with control pressure.

[0033] In an improved embodiment of the pre-control valve of the logic valve mentioned earlier, the pre-control valve has a position, particularly between two end positions, in which the two control chambers are fluidly connected not only to the control pressure medium chamber but also to the low-pressure chamber. In this way, the pressure in the two control chambers can be precisely and in opposite directions adjusted between the two end positions by changing the position of the pre-control valve.

[0034] In one improved embodiment, the logic valve, mentioned for the first time, has a pre-control valve with a first throttling cross-section, through which a first fluid connection between the pressure medium chamber and the first control chamber can be controlled. Furthermore, the pre-control valve has a second throttling cross-section, through which a second fluid connection between the low-pressure chamber and the second control chamber can be controlled. Additionally, the pre-control valve has a third and a fourth throttling cross-section; the third throttling cross-section controls the fluid connection between the pressure medium chamber and the second control chamber, and the fourth throttling cross-section controls the fourth fluid connection between the low-pressure chamber and the first control chamber.

[0035] In particular, the changes in the first and second throttling cross sections are opposite to the changes in the third and fourth throttling cross sections.

[0036] Correspondingly, the changes in the first and second throttling cross sections are in the same direction as each other, and the changes in the third and fourth throttling cross sections are in the same direction as each other.

[0037] In one improved embodiment, the valve body of the logic valve, mentioned at least for the first time, has a first control surface that acts particularly in the direction of decreasing flow cross-section and a particularly smaller second control surface that reacts to the first control surface. These two control surfaces can be selectively fluidly connected to a pressure medium container or a pressure medium tank, or both, via a pre-control valve of the logic valve. Furthermore, the valve body of the logic valve mentioned for the first time has a third control surface that acts against the first control surface and can be fluidly connected to the pressure medium container.

[0038] The second and third control surfaces act in the direction of increasing flow cross-section. Here, the pressure of the pressure medium container acts particularly persistently on the third control surface, while the second control surface can be loaded by a pre-control valve with a smaller low pressure and control pressure, as well as pressure values ​​in between.

[0039] In an alternative improvement, the valve body of the logic valve mentioned at least for the first time has a first control surface and a counteracting, particularly smaller, second control surface. Here, only the first control surface can be selectively fluidly connected to a control pressure medium source or a pressure medium reservoir, or both, via the pre-control valve. Conversely, the second control surface is permanently fluidly connected to the control pressure medium source. Furthermore, the valve body of the logic valve mentioned for the first time has a third control surface that acts in opposition to the first control surface and can be fluidly connected to a pressure medium container.

[0040] In this alternative, the second and third control surfaces thus function in the direction of increasing flow cross-section. Here, as in the aforementioned alternative, the pressure of the pressure medium container acts particularly consistently on the third control surface, while the second control surface is always loaded to control the pressure. Consequently, the logic valve mentioned for the first time opens in a controlled manner.

[0041] In one improved embodiment, the logic valve mentioned for the first time has a second pressure chamber that is fluidly connected to, and in particular to, the pressure chamber of a hydraulic cylinder.

[0042] In one improved design, the second pressure chamber of the logic valve is partially defined by a face of the valve body that does not affect the flow cross-section. In this way, the partially high operating pressures, particularly up to 700 bar, which operate in the pressure chamber of the hydraulic cylinder, do not affect the opening or closing of the logic valve mentioned earlier, thus eliminating the need for a reaction to the high operating pressures of the hydraulic cylinder with respect to the logic valve, especially its pre-control.

[0043] The last surface mentioned is constructed such that it has no active components in the regulating direction of the valve body, and is specifically constructed as a circumferential surface. Therefore, the working pressure in the pressure chamber acts only radially on the valve body.

[0044] A hydraulic assembly, particularly a hydraulic press, especially a large press, as already mentioned, includes a filling valve assembly according to the invention. Furthermore, the hydraulic assembly also includes a hydraulic cylinder, particularly a press cylinder, with a piston defining a pressure chamber. This pressure chamber is fluidly connected to a logic valve, through which it can be supplied for re-drawing and releasing pressure media. Additionally, the assembly includes, in particular, a pressure media container for loading. The pressure chamber is fluidly connected on one hand to the logic valve of the filling valve assembly, and the pressure media container is fluidly connected on the other hand. In this way, pressure media can be re-drawn into and released from the pressure chamber, at least through the continuously adjustable flow cross-section of the logic valve of the filling valve assembly, particularly controlled according to the rated variation curve of the pressure in the pressure chamber and / or the force of the piston.

[0045] In an improved embodiment, to enable adjustment of the force in the hydraulic cylinder, the component includes a force detection unit and / or a pressure detection unit, through which the force of the piston and / or the pressure in the pressure chamber of the hydraulic cylinder can be detected. In this way, the measured values ​​of force and / or pressure can be used to control the hydraulic cylinder via one or more valves during re-suction and / or depressurization.

[0046] In one improved embodiment, the component has a control unit in which rated variation curves of force and / or pressure, particularly time-related, are stored.

[0047] In one improved embodiment, the pre-control valve of at least the logic valve mentioned above can be controlled by a control unit based on the rated variation curve and the detected pressure or force.

[0048] In one improved embodiment, the pressure medium container is composed of a loaded hydraulic reservoir or pressure medium tank. By loading, the pressure medium can be readily replenished from the pressure medium container for re-drawing into the pressure chamber, and upon release or depressurization, the pressure medium flows back from the pressure chamber through a logic valve.

[0049] When fixed in the closed position, the corresponding logic valve is held in place by a spring that preloads the valve body to its closed position.

[0050] Regardless of other design options for the filling valve assembly or its components, the following improvement proves advantageous: in which the control pressure medium source is fluidly connected to or can be fluidly connected to the loaded pressure medium container, particularly a hydraulic storage tank. Therefore, for controlling one or more logic valves, especially for loading pressure medium onto the aforementioned first and / or second control surfaces or surfaces, a control pressure with minimal fluctuations can be provided, thereby improving the quality of pressure or force control or regulation of the hydraulic cylinder.

[0051] In particular, the container or the hydraulic storage device is connected to a flow path for the control pressure medium. In an improved embodiment, the container or the hydraulic storage device is connected to the flow path for the control pressure medium via a valve, particularly an adjustable throttling device.

[0052] Additionally, an evacuation flow path can be provided from the container or hydraulic storage tank to the pressure medium tank. Adjustable or switchable throttling devices can be arranged here to release the pressure medium from the container / hydraulic storage tank.

[0053] Optionally, a pressure relief valve may be provided for the protection of the container / hydraulic storage tank.

[0054] Optionally, a pressure detection unit is provided for detecting the pressure in the aforementioned container or hydraulic storage tank. Attached Figure Description

[0055] The accompanying drawings illustrate a hydraulic assembly according to the invention, configured as a large hydraulic press according to two embodiments. The invention will now be described in detail with reference to the illustrations in these drawings. Wherein are shown: Figure 1 The hydraulic components of a large press configured hydraulically according to the first embodiment are shown, and Figure 2 The hydraulic components of a large press configured as hydraulic according to the second embodiment are shown. Detailed Implementation

[0056] Figure 1 A hydraulic circuit diagram of a large hydraulic press according to a first embodiment is shown. The large press has one or at least one hydraulic cylinder 2 with a pressure chamber 4, which is partially defined by a piston 6. In the illustrated embodiment, gravitational acceleration g acts on the piston 6 such that gravitational acceleration causes the piston to accelerate toward the stretching pad (Ziehkissen) (not shown) to form a rapid stroke, wherein the pressure chamber 4 increases.

[0057] To control the filling and release of pressure medium from pressure chamber 4, the pressure chamber can be fluidly connected to a loaded pressure medium container or pressure medium storage 34 via valves 8, 16, and 24.

[0058] To apply the clamping force of hydraulic cylinder 2, the large press has a high-pressure medium source 36 in an open hydraulic circuit, which is fluidly connected to pressure chamber 4 via working line 38. In the illustrated embodiment, the high-pressure medium source 36 is constructed as an axial piston pump with an adjustable extrusion volume. Other designs are also feasible.

[0059] Valves 8, 16, and 24 have a structure consisting of pre-control valves 12, 20, and 28 and logic valves 10, 18, and 26. In the illustrated embodiment, the second valve 16 and the third valve 24 are designed identically in terms of their pre-control valves 20 and 28 and logic valves 18 and 26 and their nominal values. In contrast, the nominal values ​​can be designed differently.

[0060] The pre-control valves 20 and 28 are configured as 4 / 2 switching valves with four connections and two switching positions. The logic valves 10, 18, and 26 are configured as the applicant's LC2A logic valves, as is known in the prior art.

[0061] Unlike the second and third pre-control valves 20 and 28, the pre-control valve 12 is configured as a 4 / 2 directional valve capable of continuous, and especially proportional, adjustment. This is used to continuously adjust the flow cross-section 14 of the logic valve 10 according to the invention.

[0062] according to Figure 1The large press also has a pressure medium tank, which is constructed as a box T.

[0063] In order to control the pressure control logic valves 10, 18, and 26, the large press has a control pressure medium source 32, which is constructed as an adjustable axial piston pump in an open hydraulic circuit.

[0064] In order to detect the pressure in pressure chamber 4, the large press has a pressure detection unit 40.

[0065] Logic valves 10, 18, and 26 have valve bodies 42, 44, and 46, respectively. Because of their structural similarity, only logic valve 10 will be used to describe the logic valve.

[0066] The valve body 42 has a first control surface 48 defining a rear chamber of the valve body, a smaller second control surface 50 (designed as an annular surface) that reacts to the first control surface 48, and a third control surface 52 that acts in the same orientation as the second control surface. Through the valve body 42, in the logic valve 10, a first pressure chamber A, fluidly connected to the pressure medium container 34, can be fluidly separated from and connected to a second pressure chamber B, fluidly connected to the pressure chamber 4. Here, the valve body 42 is located on the valve seat of the logic valve 10. When the valve body 42 is lifted from the seat, the flow passage section 14 of the logic valve 10 opens. Then, the pressure medium container 34 is fluidly connected to the pressure chamber 4 through the flow passage section 14, or otherwise separated.

[0067] The pre-control valve 12, provided to the logic valve 10, has a control pressure medium chamber P, which is fluidly connected to a control pressure medium source 32 via a control pressure medium flow path 54. The pre-control valve also has a low-pressure chamber T, which is fluidly connected to a pressure medium tank T via a low-pressure flow path 56. Furthermore, the pre-control valve has a first pressure chamber 58, which, in the illustrated embodiment, is permanently fluidly connected to a first control surface 48 and a second control surface 50. Additionally, the pre-control valve has a second control chamber 60, which, in the illustrated embodiment, is permanently switched with respect to the flow cross-section 14. This switching is achieved via a plug 62 in the path from the second control chamber 60 to the second control surface 50. If the plug is removed and, for example, arranged in the region of path Z1, then the second control chamber 60 is fluidly connected to the second control surface 50 and the first control chamber 58 is fluidly separated from the second control surface 50.

[0068] The pre-control valve 12 has a first end position 12a, in which the control pressure medium chamber P is fluidly connected to the first control chamber 58, and the low-pressure chamber T is fluidly connected to the second control chamber 60. The first end position 12a is the basic position of the pre-control valve 12 with its spring preload. Furthermore, the pre-control valve has a second end position 12b, in which the control pressure medium chamber P is fluidly connected to the second control chamber 60, and the low-pressure chamber T is fluidly connected to the first control chamber 58. Between end positions 12a and 12b, the pre-control valve 12 can be proportionally and continuously adjusted to the intermediate position 12c by an electromagnet.

[0069] In the illustrated embodiment, the first control chamber 58 is permanently connected not only to the first control surface 48 but also to the second control surface 50 via control lines. Because the second control chamber 60 is permanently switched off (see above), the same pressure acts on control surfaces 48 and 50. Here, the combined closing force of the first control surface 48 is greater than the opening force of the second control surface 50 according to the area ratio. The pressure mentioned last is approximately the control pressure in the control pressure medium chamber P, i.e., the control pressure of the control pressure medium source 32, in the first end position 12a, and approximately the pressure in the low-pressure space T, i.e., the tank pressure, in the second end position 12b. In the intermediate position 12c, the pressure has a value in between that can continuously change.

[0070] Because the area of ​​the first control surface 48 is larger than that of the second control surface 50, which acts in the opposite direction, the pressure generated in the first control chamber 58 always acts in the direction of decreasing flow cross-section. Furthermore, the valve body 42 of the logic valve 10 is pre-tensioned to the closed position (flow cross-section 14 equals zero) via a spring.

[0071] The pressure of the pressure medium container 34 reacts to the closing pressure on the valve body 42 because the pressure medium container is permanently fluidly connected to the third control surface 52 of the valve body 42 via the storage line 61.

[0072] The following describes the filling of pressure chamber 4 during the rapid stroke, in which piston 6 is discharged during free fall, and the force application stroke in which piston 6 applies a forming force, and the pressure-controlled or force-controlled decompression of pressure chamber 4 after the force application stroke.

[0073] The piston 6 is arranged in its initial position above the pressure chamber 4 according to the accompanying drawings, wherein the pressure chamber 4 has its minimum volume. In this position, it is held by a hydraulically operated device (not shown). If the piston 6 is to move toward the tension pad (not shown), this is done with maximum speed by eliminating the aforementioned holding force and by accelerating the piston 6 by gravitational acceleration g. Here, the pressure medium must be drawn back into the pressure chamber 4 at a sufficient speed in order to avoid cavitation in particular.

[0074] To this end, the valve pistons 42, 44, and 46 of valves 8, 16, and 24 are rapidly adjusted to the maximum flow cross sections 14, 22, and 30. This is achieved by rapidly reducing the pressure acting on the valve bodies 42, 44, and 46 during closure, which is applied to the corresponding first control surface 48.

[0075] This is achieved for valve 8 by electromagnetically switching pre-control valve 12 from its spring-preloaded basic position 12a to its second end position 12b. The first control surface 48 then connects to the low-pressure chamber T of the pre-control valve 12 and thus to the pressure medium tank T. The same applies to the second control surface 50. Because the third control surface 52 is permanently connected to the pressure medium container 34 preloaded to 5 bar, the valve body 42 of valve 8 is lifted from the valve seat, and the flow cross section 14 reaches its maximum value. Regarding the second valve 16 and the third valve 24, the pre-control valves 20 and 28 are also electromagnetically actuated, thereby connecting the first control surface 48 of logic valves 18 and 26 to the pressure medium tank T. Therefore, valve bodies 44 and 46 also open, releasing the flow cross sections 22 and 30. Then, as piston 6 descends, the maximum pressure medium volume flow is replenished into pressure chamber 4 via the storage line 61 through the flow cross sections 14, 22, and 30.

[0076] Just before reaching the stretching pad, the piston 6 is braked by a hydraulic mechanical device (not shown).

[0077] Next is the force application stroke, in which pressure chamber 4 is supplied with a pressure medium having an operating pressure of approximately 630 bar in the illustrated embodiment via high-pressure medium source 36.

[0078] Here, advantageously, no regulating force is generated by the operating pressure on the valve pistons 42, 44, and 46 of the logic valves 10, 18, and 26. This is because no axially acting, i.e., non-regulating, control surface is provided on the valve bodies 42, 44, and 46 regarding the second pressure chamber B of the logic valves 10, 18, and 26 with the operating pressure. The high pressure (630 bar) therefore acts only radially, rather than axially, on the valve pistons 42, 44, and 46. Correspondingly, only a relatively small control pressure is required to keep the logic valves 10, 18, and 26 closed (which is necessary during the force application stroke), the control pressure existing on the first control surface 48 of the respective logic valves 10, 18, and 26. Therefore, despite the high operating pressure of the filling valve assembly 1, the spool valves 10, 18, and 26, which are advantageously simple in device technology because they cannot be designed for such high pressures, can be used instead of the spool valves.

[0079] Next, pressure chamber 4 is depressurized. Here, the pressure in pressure chamber 4 is continuously monitored by pressure detection unit 40. This pressure should follow the rated change curve over time so that the pressed part or product achieves its specified quality and grade. Therefore, the large press has a control unit (not shown) in which the rated change curve of force, and especially the pressure in pressure chamber 4, is stored in relation to time. Here, the control unit compares the actual pressure change curve detected by detection unit 40 with the rated change curve and intervenes in a controlled manner. During depressurization, the force control of the hydraulic cylinder is performed only through pre-control valve 12 and logic valve 10. Instead, pre-control valves 20 and 28 switch to their spring-preloaded basic position, in which the control pressure at the control pressure medium chamber P acts fully on the first control surface 48 of valve bodies 44 and 46, thereby closing logic valves 18 and 26.

[0080] To precisely stop the force of piston 6, or the pressure variation curve in pressure chamber 4, the control unit manipulates the solenoid of pre-control valve 12. This is based on the rated variation curve and the detected pressure. Depending on the deviation from the rated variation curve, the flow cross section 14 must be increased (pressure in pressure chamber 4 is too high, pressure reduction is too low) or decreased (pressure in pressure chamber 4 is too low, pressure reduction is too strong). For this purpose, in particular, the intermediate position 12c of pre-control valve 12 is activated, which allows for fine control of the pressure applied on the first control surface 48, which operates in a closed state, and the second control surface 52, which operates in an open state.

[0081] according to Figure 2 The second embodiment of the hydraulic large press 101 largely corresponds to that according to Figure 1 A large hydraulic press. Therefore, in the embodiments, the same components are given the same reference numerals in the drawings. The large hydraulic press 101 differs from the large press in the area of ​​its valve 8, more precisely in the area of ​​the logic valve 10. Therefore, the large press 101 has a valve 108, which is similar to... Figure 1 Valve 8, but differs in terms of pressure medium loading on the second control surface 50. Here, the difference lies in... Figure 2 The logic valve 110. Rather than in Figure 1 Unlike the corresponding components, logic valve 110 has an additional plug 63 through which the first control surface 48 and the second control surface 50 are fluidly separated. Furthermore, the latter is in a persistent pressure medium connection with the control pressure medium source 32 via a control pressure medium flow path 54. Therefore, the second control surface 50 is persistently loaded to control the preferred constant control pressure of the pressure medium source 32.

[0082] This enables the flow passage cross section 14 to be opened controllably when the pressure on the first control surface 48, which is in a closed state, decreases.

[0083] The shut-off pressure applied to the first control surface 48 is preferably less than 100 bar.

[0084] The control pressure is preferably between 100 bar and 200 bar, especially between 100 bar and 180 bar.

[0085] The working pressure in pressure chamber 4 during the force application stroke is preferably greater than 400 bar, especially 450 bar, particularly in the range of 600 bar to 650 bar, or higher, especially 630 bar up to 700 bar.

[0086] A filling valve assembly with a logic valve is disclosed, through which a pressure medium can be drawn back into and released from the pressure chamber of an actuator. Here, the logic valve is pre-controlled by a continuously adjustable proportional valve, so that its flow cross-section can not only be switched but also proportionally adjusted. In this way, especially when releasing the pressure medium, precise control of the actuator's force is achieved using a logic valve that is technically simple.

[0087] Furthermore, a hydraulic assembly, particularly a large press, with a filling valve assembly is disclosed, having an actuator through which a pressure medium is supplied, a control pressure medium source for controlling a logic valve, and a pressure medium container that provides pressure medium for re-suction and absorbs the pressure medium upon release.

Claims

1. A hydraulic filling valve assembly for re-drawing a pressure medium into and from a pressure chamber (4) of a hydraulic cylinder (2), the hydraulic filling valve assembly having a valve (8, 108) having a continuously adjustable flow cross-section (14) through which the pressure medium can be re-drawn into the pressure chamber (4) and released from the pressure chamber (4) in a pressure-controlled or force-controlled manner, characterized in that, The valves (8, 108) have logic valves (10, 110) forming a continuously adjustable flow cross section (14) of the valves (8, 108). A second pressure chamber of the logic valves (10, 110), which is fluidly connected to the pressure chamber (4) of the hydraulic cylinder (2), is partially defined by a face of the valve body (42) of the logic valves (10, 110), which does not function with respect to the flow cross section (14). The valves (8, 108) also have a pre-control valve (12) that can be continuously adjusted, and the logic valves (10, 110) can be controlled in a continuously adjustable manner via the pre-control valve. The flow cross section (14) of the pre-control valve (110) has a control pressure medium chamber (P) that can be fluidly connected to a control pressure medium source (32), a low pressure chamber (T) that can be fluidly connected to a pressure medium tank, and a first control chamber (58) that can be fluidly connected to a first control surface (48) of the valve body (42) of the logic valve (10, 110) that acts in the direction of decreasing flow cross section (14), wherein the pre-control valve (12) has a first end position (12a) in which the first control chamber (58) is connected to the control pressure medium chamber (P) and separated from the low pressure chamber (T).

2. The filling valve assembly according to claim 1, wherein, The valves (8, 108) have a pre-control valve (12) that can be proportionally adjusted and through which the flow cross section (14) of the logic valves (10, 110) can be controlled in a proportionally adjustable manner.

3. The filling valve assembly according to claim 2, having one or more additional logic valves (18, 26) fluidly connected in parallel with the logic valves (10, 110), capable of re-drawing the pressure medium into the pressure chamber (4) through their flow cross-section or their additional flow cross-sections (22, 30).

4. The filling valve assembly according to claim 3, wherein, The additional logic valve or at least one of the additional logic valves (18, 26) is configured to have a switchable flow cross section (22, 30), or wherein the additional logic valve or at least one of the additional logic valves is configured to have a continuously adjustable flow cross section.

5. The filling valve assembly according to claim 4, characterized in that, At least one of the additional logic valves or the additional logic valves (18, 26) is configured as an openable check valve.

6. The filling valve assembly according to claim 4, wherein, The additional logic valve or at least one of the additional logic valves (18, 26) is configured as a switching valve.

7. The filling valve assembly according to claim 6, wherein, The pre-control valve has a second control chamber that is fluidly connected to a second control surface of the valve body that acts in the direction of increasing flow cross-section, or wherein... The pre-control valve (12) has a second control chamber (60) that switches inactively with respect to the flow cross section (14).

8. The filling valve assembly according to claim 7, wherein, The pre-control valve (12) has a first end position (12a) in which the second control chamber (60) is connected to the low-pressure chamber (T) and separated from the control pressure medium chamber (P).

9. The filling valve assembly according to claim 7, wherein, The pre-control valve (12) has a second end position (12b) in which the first control chamber (58) is connected to the low-pressure chamber (T) and separated from the control pressure medium chamber (P), and in the second end position, the second control chamber (60) is connected to the control pressure medium chamber (P) and separated from the low-pressure chamber (T).

10. The filling valve assembly of claim 7, wherein, The pre-control valve (12) has a first end position (12a) and a second end position (12b), and the pre-control valve (12) has a position (12c) between the first end position (12a) and the second end position (12b), in which the two control chambers (58, 60) are fluidly connected not only to the control pressure medium chamber (P) but also to the low pressure chamber (T).

11. The filling valve assembly of claim 10, wherein, The pre-control valve (12) has a first throttling cross section and a second throttling cross section. The first throttling cross section controls the first fluid connection between the regulating pressure medium chamber (P) and the first control chamber, and the second throttling cross section controls the second fluid connection between the low-pressure chamber (T) and the second control chamber. The pre-control valve also has a third throttling cross section and a fourth throttling cross section. The third throttling cross section controls the fluid connection between the regulating pressure medium chamber (P) and the second control chamber, and the fourth throttling cross section controls the fourth fluid connection between the low-pressure chamber (T) and the first control chamber.

12. The filling valve assembly according to any one of claims 1 to 11, wherein, The valve body (42) of the logic valve (10) has a first control surface (48) and a second control surface (50) that acts opposite to the first control surface. The first control surface and the second control surface can be selectively fluidly connected to the control pressure medium source (32) or the pressure medium tank or both via the pre-control valve (12). The valve body (42) also has a third control surface (52) that acts opposite to the first control surface (48) and can be fluidly connected to or connected to the pressure medium container (34).

13. The filling valve assembly according to any one of claims 1 to 11, wherein, The valve body (42) of the logic valve (10) has a first control surface (48) and a smaller second control surface (50) that acts opposite to the first control surface. The first control surface and the second control surface can be selectively fluidly connected to the control pressure medium source (32) or the pressure medium tank or both via the pre-control valve (12). The valve body (42) also has a third control surface (52) that acts opposite to the first control surface (48) and can be fluidly connected to or connected to the pressure medium container (34).

14. The filling valve assembly according to any one of claims 1 to 11, wherein, The valve body (42) of the logic valve (110) has a first control surface (48) and a second control surface (50) that acts opposite to the first control surface. The first control surface (48) can be selectively fluidly connected to the control pressure medium source (32) or the pressure medium tank or both via the pre-control valve (12), and the second control surface (50) is permanently fluidly connected to the control pressure medium source (32). The valve body (42) has a third control surface (52) that acts opposite to the first control surface (48) and can be fluidly connected to or connected to the pressure medium container (34).

15. The filling valve assembly according to any one of claims 1 to 11, wherein, The valve body (42) of the logic valve (110) has a first control surface (48) and a smaller second control surface (50) that acts opposite to the first control surface. The first control surface (48) can be selectively fluidly connected to the control pressure medium source (32) or the pressure medium tank or both via the pre-control valve (12), and the second control surface (50) is permanently fluidly connected to the control pressure medium source (32). The valve body (42) has a third control surface (52) that acts opposite to the first control surface (48) and can be fluidly connected to or connected to the pressure medium container (34).

16. A hydraulic assembly having a filling valve assembly (1, 101) constructed according to any one of claims 1 to 15 and a hydraulic cylinder (2) having a piston (6) defining a pressure chamber (4), wherein, The logic valve (10) of the filling valve assembly (1, 101) is fluidly connected to the loaded pressure medium container (34) and the pressure chamber (4) of the assembly, and wherein the pressure medium can be drawn back into the pressure chamber (4) by the continuously adjustable flow cross section (14) of the logic valve (10) of the filling valve assembly (1, 101) and the pressure medium can be released from the pressure chamber (4) in a manner controlled according to the pressure of the pressure chamber (4) and / or the force of the piston (6).

17. A hydraulic press comprising a filling valve assembly (1, 101) constructed according to any one of claims 1 to 15 and a hydraulic cylinder (2) having a piston (6) defining a pressure chamber (4), wherein, The logic valve (10) of the filling valve assembly (1, 101) is fluidly connected to the loaded pressure medium container (34) and the pressure chamber (4) of the assembly, and wherein the pressure medium can be drawn back into the pressure chamber (4) by the continuously adjustable flow cross section (14) of the logic valve (10) of the filling valve assembly (1, 101) and the pressure medium can be released from the pressure chamber (4) in a manner controlled according to the pressure of the pressure chamber (4) and / or the force of the piston (6).

18. A large press comprising a filling valve assembly (1, 101) constructed according to any one of claims 1 to 15 and a hydraulic cylinder (2) having a piston (6) defining a pressure chamber (4), wherein, The logic valve (10) of the filling valve assembly (1, 101) is fluidly connected to the loaded pressure medium container (34) and the pressure chamber (4) of the assembly, and wherein the pressure medium can be drawn back into the pressure chamber (4) by the continuously adjustable flow cross section (14) of the logic valve (10) of the filling valve assembly (1, 101) and the pressure medium can be released from the pressure chamber (4) in a manner controlled according to the pressure of the pressure chamber (4) and / or the force of the piston (6).

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