Two-stage hydraulic press system and method for operating a two-stage hydraulic press system

Abstract

The present invention relates to a two-stage hydraulic press system (100) having a first drive mode and a second drive mode, the two-stage hydraulic press system (100) comprises: a movable pressing component (104); a first hydraulic cylinder (110) comprising a first piston (112); a second hydraulic cylinder (120) comprising a second piston (122) defining two chambers (124a, 124b) of the second hydraulic cylinder (120); a first servo-driven pump (130) configured to deliver a first fluid to the first hydraulic cylinder (110); a second servo-driven pump (140) configured to deliver a second fluid to the second hydraulic cylinder (120); and a flow control valve (150), connected to the chambers (124a, 124b) of the second hydraulic cylinder (120), configured to engage and disengage the second piston (122), wherein the first piston (112) and the second piston (122) are coaxially mechanically interconnected and configured to move in unison to induce a movement of the movable pressing component (104); wherein, in the first drive mode, the second piston (122) is configured to be disengaged and at least the first servo-driven pump (130) is configured to induce a movement of the movable pressing component (104) with a first speed; and wherein, in the second drive mode, the second piston (122) is configured to be engaged and at least the second servo-driven pump (140) is configured to induce a movement of the movable pressing component (104) with a second speed.

Description

Technical field

[0001] The present description realates to a hydraulic press system, a method for operating a hydraulic press system, and a control unit for performing the steps of said method. In particular, the inventive concept relates to a two-stage hyraulic press system.Background

[0002] Hydraulic presses are widely used for various applications, for example in metal forming and bending, owing to their ability to exert controlled force in a precise manner. However, despite their extensive utilization, existing hydraulic press systems have limitations.

[0003] Many existing hydraulic press systems suffer from inefficiencies in energy consumption. Pressure fluctuations and inadequate control systems may result in wasteful energy usage, thereby contributing to higher operational costs.

[0004] In addition, existing solutions often employ a servo-driven pump to control a small piston area, along with a switching valve (on / off) to change over to a larger piston area at a given pressure. This switching from a small to a larger area can result in a pressure collapse, interrupting the piston speed and potentially causing pressure peaks in the system.

[0005] In light of these challenges, there is a need for an improved hydraulic press system that addresses these disadvantages while enhancing versatility.Summary

[0006] An objective of the present description is to provide a hydraulic press system for facilitated manufacturing across various products and processes.

[0007] Another objective is to provide a method for operating a hydraulic press system.

[0008] A further objective is to provide a control unit for controlling operation of a hydraulic press system.

[0009] These and other objectives are at least partly met by the invention as defined in the independent claims. Preferred exemplifying embodiments are set out in the dependent claims.

[0010] According to a first aspect, there is provided a two-stage hydraulic press system having a first drive mode and a second drive mode, the system comprising: a movable pressing component; a first hydraulic cylinder comprising a first piston defining two chambers of the first hydraulic cylinder; a second hydraulic cylinder comprising a second piston defining two chambers of the second hydraulic cylinder; a first servo-driven pump configured to deliver a first fluid to the first hydraulic cylinder; a second servo-driven pump configured to deliver a second fluid to the second hydraulic cylinder; and a flow control valve, connected to the chambers of the second hydraulic cylinder, configured to engage and disengage the second piston, wherein the first piston and the second piston are mechanically interconnected and configured to induce a movement of the movable pressing component in unison; wherein, in the first drive mode, the second piston is configured to be disengaged and at least the first servo-driven pump is configured to induce a movement of the movable pressing component with a first speed; and wherein, in the second drive mode, the second piston is configured to be engaged and at least the second servo-driven pump is configured to induce a movement of the movable pressing component with a second speed.

[0011] Hence, the two-stage hydraulic press system facilitates switching between drive modes of a hydraulic press while maintaining full speed control of the movable pressing component during the switching. Hereby, the two-stage hydraulic press system may enable precise and efficient forming and shaping of materials, and a high machine output and long service life may be achieved. In other words, a smooth transition between drive modes of the hydraulic press is provided.

[0012] The two hydraulic cylinders may have mechanically connected piston rods so that the piston rods always move together as one unit for controlling the speed of the movable pressing component.

[0013] The movable pressing component may be a movable forming component. The movable pressing component may be any suitable tool, such as a tool configured for exerting a force on an object or a material, e.g. a ram. The movable pressing component may encompass a range of elements configured for specific applications. Such movable pressing components may include, but are not limited to, die sets for shaping materials, molds for molding, rams or plungers for applying force, V-blocks for securing cylindrical workpieces, blank holders for sheet metal forming, punches for cutting or piercing, pressure plates for even pressure distribution, forming tools for various operations, and / or bolster plates providing a stable work surface.

[0014] The movable pressing component may be interchangeable. Hence the two-stage pressing system may serve in diverse industries, e.g. in plastics and / or metalworking. In other words, the two-stage pressing system may be configured for use in pressing and / or forming various kinds of materials.

[0015] The chambers of the first hydraulic cylinder may be smaller than the chambers of the second hydraulic cylinder. In particular, a radius of the chambers of the first hydraulic cylinder may be smaller than a radius of the chambers of the second hydraulic cylinder. In other words, a piston area of the first piston may be smaller than a piston area of the second piston, and / or the first hydraulic cylinder may be a smaller hydraulic cylinder than the second hydraulic cylinder. Hence, the flow control valve may be used to disengage the larger piston area such that that the smaller hydraulic cylinder may move both pistons with a low resistance.

[0016] The first fluid and / or the second fluid may be hydraulic fluid. The first fluid and / or the second fluid may, e.g., comprise oil, mineral oil-based fluids, synthetic hydraulic fluids, and / or water-glycol mixtures.

[0017] The flow control valve may be a proportional flow control valve and / or an electrical flow control valve. The flow control valve may be configured to control and / or regulate a flow rate of the second fluid, e.g. by varying the size of the flow passage via a restrictor. The flow control valve may, e.g., control and / or regulate a flow rate in response to an electrical signal.

[0018] The regulated flow rate may adjust a fluid level in the chambers of the second hydraulic cylinder and / or a pressure on the second piston. The flow control valve may use a valve spool for controlling the flow. An electrical signal may be supplied valve spool such that a shift in the valve spool is provided. Thus, the flow control valve may provide precise regulation of a variable flow of the second fluid. In particular, an electrically controlled flow control valve may allow for a precise control of the opening and closing of the flow control valve and good repeatability. The flow of the second fluid between the chambers of the second hydraulic cylinder may, in the first drive mode with the flow control valve disengaging the second piston, be provided by the first piston moving in the first speed. The second piston may then move together with the first piston. During such movement, the second fluid may flow between the two chambers of the second hydraulic cylinder. When switching to the second drive mode, the first hydraulic cylinder may first be changed, e.g. lowered, in speed to the second speed. The second servo-driven pump may be configured to operate in the second speed. In the first drive mode, the second servo-driven pump may be inactive, and may thereby be activated when the movement of the pistons are controlled to the second speed. The flow control valve may then be operated to engage the second piston. The flow control valve may be closed when operated to engage the second piston. The second servo-driven pump may then induce movement of the second piston, and thereby also the movable pressing component, in the second speed.

[0019] Some components of the two-stage hydraulic press system may be connected by pipes, conduits, and / or hoses, which in turn may, e.g., allow for the first and second fluids to travel between the components. The components between which the fluid flow may be the servo-driven pumps and the hydraulic cylinders. Thus, transmission of force and movement may be enabled.

[0020] The first and second servo-driven pumps may provide the ability to vary a direction and / or speed of the respective first and second fluids. The variable speed may allow for precise control over the flow rate of the pump. Hence, a speed of operation of the first and second servo-driven pumps may be quickly adjusted. In other words, adjustments and / or fine-tuning in position, speed, and / or force of the first and second pistons may be provided.

[0021] The first and second pistons may be coaxially mechanically interconnected, and thereby configured to move in unison to induce the movement of the movable pressing component. The pistons may then be arranged in series on top of each other, preferably with the first piston arranged above the second piston. In another embodiment, the two pistons may be arranged next to each other, in parallel. Together they may operate on the same movable pressing component. The two pistons may be configured to operate on and / or be attached to different portions of the movable pressing component. The two pistons arranged in parallel next to each other may be mechanically interconnected such that they in unison induce the movement of the movable pressing component. The mechanical interconnection may be provided by a direct attachment or coupling to each other at ends of the pistons, or via an interconnection member to which both pistons are attached, and which is connected or attached to the movable pressing component.

[0022] The two-stage hydraulic press system may further comprise a first and second hydraulic valve system configured to respectively control a fluid compression volume of the first and second fluids to and from the first and second hydraulic cylinders.

[0023] The first and second hydraulic valve systems may, respectively, control a necessary fluid compression volume to and from each hydraulic cylinder with a changing load. In other words, the first and second hydraulic valve systems may each handle a compression volume required to build a pressure in the respective first and second hydraulic cylinder and / or a force of the respective first and second pistons. Hence, there may be an improved accuracy in the movement of the movable pressing component. Additionally, the ability to modulate the compression volume of the fluid within the hydraulic cylinders may enable efficient energy utilization and / or reduced energy consumption.

[0024] The first speed may be larger than the second speed. In other words, the movable pressing component may move with a faster speed when the two-stage hydraulic press system is in the second drive mode than when the two-stage hydraulic press system is in the first drive mode.

[0025] Hence, in the two-stage hydraulic press system, the movable pressing component may operate at two different speeds. When the system is in the first drive mode, the speed of the movable pressing component, referred to as the first speed, may be higher than its speed in the second drive mode, referred to as the second speed.

[0026] These speeds may essentially be magnitudes of a velocity vector, indicating that the velocity of the movable pressing component may vary. The first and second speeds may undergo gradual changes, either increasing or decreasing over time.

[0027] The maximum speed achieved by the movable pressing component in the first drive mode may exceed that in the second drive mode. In particular, the highest speed of the movable pressing component may be attained when the system operates in the first drive mode.

[0028] The first drive mode may correspond to a high-speed low-force movement of the movable pressing component, and the second drive mode may correspond to a high-force low-speed movement of the movable pressing component.

[0029] In other words, the two-stage hydraulic press system may in the first drive mode move the movable pressing component with a greater speed while being configured to exert a smaller force on an object or workpiece than when the two-stage press system is in the second drive mode. Similarly, the two-stage hydraulic press system may in the second drive mode move the movable pressing component with a smaller speed while being configured to exert a greater force on an object or workpiece than when the two-stage press system is in the first drive mode. Hence, the two-stage hydraulic press system may be utilized in applications requiring both high force and precise control.

[0030] The first drive mode may correspond to a rapid advance stage and / or an initial stage. In the first drive mode, the first servo-driven pump may advance the movable pressing component with a high speed towards the workpiece. The rapid advance stage may allow for quick positioning of the movable pressing component and thereby reduce non-productive time of the two-stage press system.

[0031] The second drive mode may correspond to a slow pressing stage and / or a second stage. In the second drive mode, the movable pressing component may, when in close proximity to the object or workpiece to be pressed, be switched to a slower speed. The slow pressing stage may provide accurate control over the force applied to the object or workpiece. In particular, the two-stage press system may, when in the second drive mode, provide a desired pressure or force such that a task may be performed, e.g., pressing, stamping, and / or forming an object or workpiece.

[0032] Hence, the use of two stages or modes may allow the hydraulic press system to provide both diverse speed and force control. The rapid advance stage may minimize idle time, while the slow pressing stage may ensure accurate force application.

[0033] The second piston may be configured to be: disengaged when the flow control valve is in an open state, allowing for the second fluid to flow between the chambers of the second hydraulic cylinder via the flow control valve, and the first and second pistons to move with low resistance; and engaged when the flow control valve is in a closed state. In other words, the second hydraulic cylinder may be disengaged when the flow control valve is open and engaged when the flow control valve is closed.

[0034] The flow control valve may operate by regulating the flow of the fluid between the chambers of the second hydraulic cylinder. The flow control valve may comprise an inlet and an outlet. The flow control valve may further comprise a throttle mechanism which may adjust and / or control a size of a flow opening in the flow control valve. The flow control valve may be configured to control the flow of the second flow between on and off, i.e. between open and closed states.

[0035] The open flow control valve may prevent the second fluid from interfering with the movement of the second piston, i.e. cause a pressure release. The flow control valve may thus function as a short-cut for the second fluid and / or a by-pass of the second piston. In other words, the second fluid may flow through the flow control valve and between the chambers of the second hydraulic cylinder. Hence the second piston may move freely. Contrary, the closed flow control valve may force the second fluid to exert a pressure on the second piston.

[0036] The two-stage hydraulic press system may comprise a first and second closed hydraulic circuit. In other words, the two-stage hydraulic press system may comprise a first closed hydraulic loop and a second closed hydraulic loop. In particular, the two-stage hydraulic press system may form a first and second closed hydraulic circuit.

[0037] The first closed hydraulic circuit may comprise the first hydraulic cylinder, the first piston, the first fluid, the first servo-driven pump, and / or the first hydraulic valve system. The second closed hydraulic circuit may comprise the second hydraulic cylinder, the second piston, the second fluid, the second servo-driven pump, the second hydraulic valve system, and / or the flow control valve.

[0038] Hence, each servo-driven pump may independently influence the motion of its corresponding piston. Thus, the two-stage hydraulic press system may facilitate control over the movement of the movable pressing component and / or the force exerted by the movable pressing component, which may lead to more precise operations of the two-stage hydraulic press system.

[0039] The first closed hydraulic circuit and / or the second closed hydraulic cylinder may correspond to a hydraulic circuit with variable load. The first and second closed hydraulic circuits may be synchronized. The first and second closed hydraulic circuits may be speed control loops. In other words, each closed hydraulic circuit may control a speed of the corresponding hydraulic cylinder / piston and / or the movable pressing component. In particular, the hydraulic valve system of a closed hydraulic circuit may control a fluid compression volume to and from the closed hydraulic circuit with a changing load.

[0040] Similarly, a third closed hydraulic circuit (sharing the benefits of the first and / or second closed hydraulic circuits) may be added to the two-stage hydraulic press system. Hence, a three-stage hydraulic press system may be provided. The hydraulic press system may particularly be scaled to any two or more stages.

[0041] The movement of the movable pressing component in the second drive mode may be configured to be induced by the first servo-driven pump and the second servo-driven pump acting on the first and second pistons, respectively. In other words, the motion of the movable pressing component, when the two-stage press system is in the second drive mode, may be caused by the combined action of the first and second servo-driven pumps on the respective first and second pistons. Thus, in the second drive mode, each closed hydraulic circuit may simultaneously be utilized to move the movable pressing component. Hence, the first closed hydraulic circuit may be synchronized with the second closed hydraulic circuit. In other words, the first and second closed hydraulic circuits may synchronously induce a movement of the movable pressing component.

[0042] Hereby, efficient use of energy may be enabled as both servo-driven pumps may work in tandem, thus reducing a load on each individual servo-driven pump. Further, the first and second servo-driven pumps acting on separate pistons may increase the force exerted by the movable pressing component and / or increase reliability of the two-stage hydraulic press system.

[0043] Alternatively, the movement on the movable pressing component, in the second drive mode, may be induced only by the second servo-driven pump, i.e. only the second closed hydraulic circuit. Hence, the first servo-driven pump and / or the first hydraulic cylinder may be disengaged when the two-stage hydraulic press system is in the second drive mode.

[0044] The first servo-driven pump may be driven by a first servomotor, and the second servo-driven pump may be driven by a second servomotor. In other words, the first servomotor may be comprised by the first closed hydraulic circuit and / or the second servomotor may be comprised by the second closed hydraulic circuit. The first servomotor may be dedicated to the first closed hydraulic circuit and / or the second servomotor may be dedicated to the second hydraulic circuit. Thus, the first closed hydraulic circuit may be driven by the first servomotor and / or the second closed hydraulic circuit may be driven by the second servomotor.

[0045] The first servo-driven pump may comprise the first servomotor and / or the second servo-driven pump may comprise the second servomotor. Hereby, the first and / or second servo-driven pump and corresponding servomotor may, respectively, form one entity.

[0046] The first and second servo motors may, respectively, enable the first and second servo-driven pumps to provide a variable direction and / or speed of the respective first and second fluids.

[0047] The first and second servomotors may provide high control over speed, position, and acceleration. Each servomotor may further provide a more energy-efficient operation than other types of motors.

[0048] The first and / or second servo-driven pump may, respectively, be a first and / or second servomotor driven pump. Moreover, the two-stage hydraulic press system may comprise a two-stage closed hydraulic transmission cylinder with servo drive.

[0049] The first servo-driven pump may be a first plurality of servo-driven pumps, and / or the second servo-driven pump may be a second plurality of servo-driven pumps. In other words, the first hydraulic cylinder / circuit may be driven by a plurality of servo-driven pump, and / or the second hydraulic cylinder / circuit may be driven by a plurality of servo-driven pumps. Hence, a greater pressure, flow, and / or flow rate of the first and / or second fluid may be achieved. In particular, a plurality of servo-driven pumps connected to the second closed hydraulic circuit may, in the second drive mode of the two-stage hydraulic press system, facilitate movement of the movable pressing component. Thus, the movable pressing component may achieve a higher speed.

[0050] The first plurality of servo-driven pumps may be driven by a first plurality of servomotors, and / or the second plurality of servo-driven pumps may be driven by a second plurality of servomotors. In other words, each servo-driven pump in first and / or second plurality of servo-driven pumps may have a corresponding servomotor. Each servo-driven pump in the first and / or second plurality of servo-driven pumps may comprise a servomotor.

[0051] The first plurality of servo-driven pumps and the first plurality of servomotors may induce the movement of the first fluid in the first closed hydraulic circuit. Similarly, the second plurality of servo-driven pumps and the second plurality of servomotors may induce the movement of the second fluid in the first closed hydraulic circuit. Thus, the first and second hydraulic cylinders / circuits may, respectively, be driven by the first and second plurality of servomotors. Hence, the movement of the movable pressing component may be induced by the first and / or second plurality of servomotors. In the first drive mode, the movable pressing component may be moved by running the first plurality of servomotors. In the second drive mode, the movable pressing component may be moved by running the second plurality of servo-driven pumps. Moreover, the movable pressing component may be moved by both the first and second plurality of servomotors, in either of the first and second drive modes.

[0052] The first plurality of servomotors may be dedicated to the first hydraulic cylinder and / or the second plurality of servomotors may be dedicated to the second hydraulic cylinder. Hereby, the first and second hydraulic cylinders / circuits may be controlled independently. Thus, the two-stage hydraulic press system may allow for precise adjustments of each hydraulic cylinder and / or corresponding piston.

[0053] The second servo-driven pump may be configured to be controlled at a rotational speed corresponding to the second speed in the second drive mode. Similarly, the first servo-driven pump may be configured to be controlled at a rotational speed corresponding to the first speed in the first drive mode. In other words, the speed at which each or some servo-driven pumps rotate, to induce a movement of the fluid running through the servo-driven pump, may correspond to the speed of the two-stage hydraulic press in the first and / or second drive mode.

[0054] The speed at which the first servo-driven pump, or the plurality of first servo-driven pumps, operate may correspond to the speed of the movable pressing when the two-stage hydraulic press system is in the first drive mode. Similarly, the speed at which the second servo-driven pump, or the plurality of second servo-driven pumps, operate may correspond to the speed of the movable pressing component when the two-stage hydraulic press system is in the second drive mode.

[0055] Moreover, the two-stage hydraulic pressing system may be scaled to a two or more staged hydraulic pressing system. In particular, an n-staged hydraulic pressing system may be provided such that n hydraulic cylinders, with corresponding pistons and servo-driven pumps, allow for n different drive modes.

[0056] According to a second aspect, there is provided a method for operating a two-stage hydraulic press system according to the first aspect, the method comprises operating a first drive mode and a second drive mode, operating the first drive mode comprises: opening the flow control valve to disengage the second piston by allowing free passage of the second fluid between the chambers of the second hydraulic cylinder via the flow control valve; driving the first servo-driven pump to deliver the first fluid to the first hydraulic cylinder; and moving, by the first piston, the movable pressing component with the first speed, and operating the second drive mode comprises: closing the flow control valve to engage the second piston; driving the second servo-driven pump to deliver the second fluid to the second hydraulic cylinder; and moving, by at least the second piston, the movable pressing component with the second speed.

[0057] It is appreciated that, the second aspect benefits from similar advantages and features as the first aspect.

[0058] In a sense, the method for operating the two-stage hydraulic press system may comprise a first drive mode, a switching drive mode, and a second drive mode. The first drive mode may be a high speed and low force drive mode and / or the second drive mode may be a high force and low speed drive mode.

[0059] In the first drive mode, the first servo-driven pump may control the first hydraulic cylinder with the first speed. The flow control valve may be open to allow free passage of second fluid between the cylinder chambers of the second hydraulic cylinder. Further, the second servo-driven pump may be deactivated and / or disengaged.

[0060] In the switching mode, and / or in a transition between the first and second drive modes, the speed of the first hydraulic cylinder may be controlled (e.g. reduced) to the second speed and the second servo-driven pump may be started and controlled to a rotational speed corresponding to the second speed. Further, the flow control valve may be closing. In some embodiments, the second servo-driven pump may be activated to operate corresponding to the second speed before the flow control valve is closed to engage the second piston.

[0061] In the second drive mode, the speed of the combined first and second hydraulic cylinders may be controlled by the first and second servo-driven pumps.

[0062] The step of moving the movable pressing component with the second speed may comprise driving the first servo-driven pump and the second servo-driven pump simultaneously, acting on the first and second pistons, respectively. In other words, the first servo-driven pump and the second servo-driven pump may, simultaneously and respectively, engage the first and second hydraulic cylinders in the second drive mode. Hence, in the second drive mode, the first and second servo-driven pump may induce the movement of the movable pressing component.

[0063] Hereby, enhanced performance of the two-stage hydraulic press system may be achieved by an increased total flow rate of the fluids and a consequently increased pressure acting on the first and second pistons. Hence, the movable pressing component may exert a greater and more controlled force on an object or workpiece.

[0064] Closing the flow control valve may comprise gradually closing the flow control valve. In other words, the closing of the flow control valve may comprise gradually restricting the flow of fluid through the flow control valve. The flow control valve may be closed gradually by gradually decreasing a size of an inlet and / or outlet of the flow control valve.

[0065] Hereby, a smoother transition between the first and second drive modes may be achieved. In particular, the transition from the first speed of the movable pressing component to the second speed of the movable pressing component may occur incrementally or progressively. Thus, a gradual shift in the speed of the movable pressing component may be achieved, hence allowing for smoother operation of the two-stage hydraulic press system.

[0066] In an example, firstly, the first servo motor driven pump controls the first hydraulic cylinder with a high speed, and the flow control valve is open to allow free passage of fluid between the cylinder chambers of the second hydraulic cylinder, whereas the second servo motor driven pump is not active or operates at a low speed. Secondly, the high speed of the first hydraulic cylinder is reduced to a lower speed and the second servo motor driven pump is started and controlled to a rotational speed translating to the second hydraulic cylinder and corresponding to the lower speed on the first hydraulic cylinder, whereas the flow control valve is closing. Thirdly, the lower speed induced by the first and second hydraulic cylinders is controlled by two closed hydraulic circuits (i.e., hydraulic drives) comprising a respective servo motor driven pump and hydraulic cylinder, wherein the two closed hydraulic circuits function as synchronized speed control loops.

[0067] According to a third aspect, there is provided a control unit configured to perform the steps of the method according to the second aspect. The control unit may be a control panel. The control unit may be for operating parameters such as pressure, speed, and / or timing. In other words, the control unit may control and / or initiate the steps of the method of the second aspect. The control unit may particularly instruct the two-stage hydraulic press system to perform a certain action and / or step.

[0068] Hereby, control and coordination of the steps and actions performed by the system may be achieved.

[0069] The control unit may be communicatively connected the respective components of the two-stage hydraulic press system. The control unit may, e.g., be connected to the flow control valve, the first servo-driven pump, the second servo-driven pump, the first servomotor, the second servomotor, the first hydraulic valve system, and / or the second hydraulic valve system.

[0070] The control unit may communicate directly or indirectly with the system of the first aspect. The control unit and / or system may, e.g., be connected to a server. The control unit and / or server may provide the system, or a plurality of systems according to the first aspect, with instructions to perform a set of steps and / or actions. The control unit and / or server may, e.g., be connected to a network of two-stage hydraulic press systems.

[0071] The control unit and / or server may initiate the first drive mode and / or switch the two-stage hydraulic system to the second drive mode. The second drive mode may be automatically initiated. The second drive mode may, e.g., be initiated when the first drive mode (i.e. first servo-driven pump and / or first hydraulic cylinder) reaches a workload threshold.

[0072] The control unit and / or server may control the flow control valve, the first servo-driven pump, the second servo-driven pump, the first servomotor, the second servomotor, the first hydraulic valve system, and / or the second hydraulic valve system. Consequently, the control unit and / or server may control an operation of the movable pressing component.Brief Description of Drawings

[0073] The above, as well as additional objects, features, and advantages of the present description, will be better understood through the following illustrative and non-limiting detailed description, with reference to the appended drawings. In the drawings like reference numerals will be used for like elements unless stated otherwise. Figure 1 schematically illustrates a two-stage hydraulic press system. Figure 2 also schematically illustrates a two-stage hydraulic press system. Figure 3 also schematically illustrates a two-stage hydraulic press system. Figure 4 also schematically illustrates a two-stage hydraulic press system. Figure 5 shows a communication diagram of a two-stage hydraulic press system, a control unit, and a server. Figure 6 shows a flowchart of a method for operating a two-stage hydraulic press system. Detailed description

[0074] In Figure 1, a schematic of a two-stage hydraulic press system 100 is illustrated. The system 100 comprises two closed hydraulic circuits 101, 102, a movable pressing component 104, a first hydraulic cylinder 110, a second hydraulic cylinder 120, a first servo-driven pump 130, a second servo-driven pump 140, and a flow control valve 150.

[0075] The first closed hydraulic circuit 101 comprises the first hydraulic cylinder 110 and the first servo-driven pump 130. The second closed hydraulic circuit 102 comprises the second hydraulic cylinder 120, the second servo-driven pump 140, and the flow control valve 150. The components of each closed hydraulic circuit 101, 102 are here interconnected via conduits such as pipes or hoses.

[0076] The first hydraulic cylinder 110 comprises a first piston 112 defining two chambers 114a, 114b of the first hydraulic cylinder 110, and the second hydraulic cylinder 120 comprises a second piston 122 defining two chambers 124a, 124b of the second hydraulic cylinder 120.

[0077] The first servo-driven pump 130 is here configured to deliver a first fluid to the first hydraulic cylinder 110, and the second servo-driven pump 140 is configured to deliver a second fluid to the second hydraulic cylinder 120.

[0078] The flow control valve 150 is connected to the chambers 124a, 124b of the second hydraulic cylinder 120. Furthermore, the flow control valve is configured to engage and disengage the second piston 122.

[0079] The movable pressing component 104 is connected to the pistons 112, 122. The movable pressing component 104 is here shown to have a square shape, however, the movable pressing component 104 may have any suitable shape. The movable pressing component 104 may be adapted to the specific object or workpiece to be pressed or shaped by the two-stage hydraulic press system 100.

[0080] Further, in Figure 1, the first hydraulic cylinder 110 is smaller than the second hydraulic cylinder 120. In particular, the first piston 112 has a smaller radius and area than the second piston 122. Hence, a movement induced by the first hydraulic cylinder 110 may be faster than a movement induced by the second hydraulic cylinder 120.

[0081] The smaller piston area of the first piston 112 and smaller volume of the chambers 114a, 114b of the first hydraulic cylinder 110 implies that less of the first fluid needs to be displaced to move the first piston 112 a certain distance. The speed of movement is inversely proportional to the volume of fluid being displaced. Since less fluid needs to be moved, the first piston 112 achieves a full stroke more quickly. This leads to faster movement of the movable pressing component 104.

[0082] Consequently, a smaller hydraulic cylinder also decreases the force that can be generated by the first hydraulic cylinder 110. In particular, the force exerted is directly proportional to the piston area. Hence, a smaller piston area means less force is available to move the movable pressing component 104.

[0083] Analogously, the second hydraulic cylinder 120 being larger implies a slower movement of the movable pressing component 104 with a higher force. Thus, the first hydraulic cylinder 110 here induces a first speed of the movable pressing component 104 which is higher than a second speed induced by the second hydraulic cylinder 120. In other words, the first hydraulic cylinder 110 provides a high-speed low-force movement of the movable pressing component 104, and the second hydraulic cylinder 120 provides a high-force low-speed movement of the movable pressing component 104.

[0084] Alternatively, for the opposite effect, the first hydraulic cylinder 110 may be larger than the second hydraulic cylinder 120.

[0085] The first piston 112 and the second piston 122 are coaxially mechanically interconnected. The pistons 112, 122 are configured to move in unison to induce a movement of the movable pressing component 104. In particular, the pistons rods of the first piston 112 and second piston 122 are coaxially and mechanically interconnected.

[0086] The pistons 112, 122 may be telescopically or rigidly interconnected. The pistons 112, 122 may be attached to a shared central shaft. Each piston rod may extend from each piston 112, 122 and connect to the central shaft. A pressure or force applied to one piston is thus transmitted to the central shaft and, consequently, to the other piston through the interconnected piston rods.

[0087] The two-stage hydraulic press system 100 is configured to provide a first and second drive mode. In the first drive mode, the second piston 122 is configured to be disengaged by the flow control valve 150, and the first servo-driven pump 130 is configured to move the movable pressing component 104 with the first speed. In the second drive mode, the second piston 122 is configured to be engaged by the flow control valve 150, and at least the second servo-driven pump 140, or the second servo-driven pump 140 and the first servo-driven pump 130, is configured to move the movable pressing component 104 with the second speed. The second servo-driven pump 140 may be configured to operate at a rotational speed corresponding to the second speed of the movable pressing component.

[0088] In particular, the second piston 122 is configured to be disengaged when the flow control valve 150 is in an open state. Thus, the second fluid will flow between the chambers 124a, 124b of the second hydraulic cylinder 120 via the flow control valve 150 and the first and second pistons 112, 122 will move with low resistance. Contrary, the second piston 122 will be engaged when the flow control valve 150 is in a closed state.

[0089] In a sense, as seen in Figure 1, the flow control valve 150 may function as a free-flow or bypass valve. The open flow control valve 150 creates an unrestricted path for the second fluid to flow in and effectively bypass the second piston 122. The second fluid can thus flow into or out of the second hydraulic cylinder 120 without restriction, thus allowing the second piston 112 to move freely.

[0090] Figure 2 show a schematic illustration of a two-stage hydraulic press system 100. The two-stage hydraulic press system 100 of Figure 2 benefits from the same discussion as the two-stage hydraulic press system 100 of Figure 1.

[0091] In Figure 2, two-stage hydraulic press system 100 further comprises a first servomotor 132 and a second servomotor 142. In particular, the first servo-driven pump 130 is here driven by the first servomotor 132, and the second servo-driven pump 140 is driven by the second servomotor 132. Thus, the first closed hydraulic circuit 101 comprises a first servomotor 132 and the second closed hydraulic circuit 102 comprises a second servomotor 142.

[0092] The first and second servomotors 132, 142 are depicted as separate entities connected to the first servo-driven pump 130 and second servo-driven pump 140. However, the first servo-driven pump 130 may comprise the first servomotor 132 and / or the second servo-driven pump 140 may comprise the second servomotor 142.

[0093] Figure 3 shows a schematic illustration of a two-stage hydraulic press system 100. The two-stage hydraulic press system 100 of Figure 3 benefits from the same discussions as the two-stage hydraulic press systems 100 of Figure 1 and Figure 2.

[0094] In Figure 3, the two-stage hydraulic press system 100 comprises a first hydraulic valve system 160 and a second hydraulic valve system 170. The first and second hydraulic valve systems 160, 170 may be provided to respectively control a fluid compression volume of the first and second fluids to and from the first and second hydraulic cylinders 110, 120.

[0095] The first hydraulic valve system 160 is connected to the first closed hydraulic circuit 101. The first hydraulic valve system 160 is arranged to be connected to a first chamber 114a of the first hydraulic cylinder 110 on one end and connected to a second chamber 114b of the first hydraulic cylinder 110 on the other end. Similarly, the second hydraulic valve system 170 is connected to the second closed hydraulic circuit 102 and arranged such that it is connected to a first chamber 124a of the second hydraulic cylinder 120 on one end and connected to a second chamber 124b of the second hydraulic cylinder 120 on the other end.

[0096] In Figure 3, a hydraulic valve system is connected to each closed hydraulic circuit 101, 102. However, it is appreciated that both closed hydraulic circuits 101, 102 may not necessarily have a hydraulic valve system. The first closed hydraulic circuit 101 may have a hydraulic valve system 160, or the second closed hydraulic circuit 102 may have a hydraulic valve system 170.

[0097] Although not shown, the first and second hydraulic valve systems 160, 170 may comprise components such as valves, pipes, and / or actuators for managing the flow of the first and second fluids into and out of the first and second hydraulic cylinders 110, 120, respectively.

[0098] Figure 4 shows a schematic illustration of a two-stage hydraulic press system 100. The two-stage hydraulic press system 100 of Figure 4 benefits from the same discussions as the two-stage hydraulic press systems 100 of Figure 1, Figure 2, and Figure 3.

[0099] In Figure 4, the second servo-driven pump 140 is comprised by two servo-driven pumps 140. In particular, the second closed hydraulic circuit 102 of the two-stage hydraulic press system 100 comprises a plurality of servo-driven pumps 140. Although not shown, the first servo-driven pump 130 may be a first plurality of servo-driven pumps 130. Hence, the first closed hydraulic circuit may comprise a plurality of servo-driven pumps 130.

[0100] Here, the first and second hydraulic valve systems 160, 170 are comprised by the two-stage hydraulic press system 100. However, it is appreciated that the two-stage hydraulic press system 100 may comprise a first and / or second plurality of servo-driven pumps 130, 140 independently of the presence of the first and second hydraulic valve systems 100.

[0101] Although not shown, the second plurality of servo-driven pumps 140 may be driven by a plurality of servomotors 142. Each servo-driven pump 140 in the second plurality of servo-driven pumps 140 may have a corresponding servomotor 142. In other words, the second plurality of servo-driven pumps 140 may be driven by a plurality of servomotors 142. In particular, each servo-driven pump 140 may comprises a servomotor 142. Alternatively, the plurality of second servo-driven pumps 140 may be driven by a single servomotor 142. The single servomotor 142 may be connected to each of the servo-driven pumps 140 in the second plurality of servo-driven pumps 140.

[0102] Similarly, although not shown, a first plurality of servo-driven pumps 130 may be driven by a first plurality of servomotors 132.

[0103] Figure 5 shows a communication diagram of a two-stage hydraulic press system 100, a control unit 2000, and a server 3000. The control unit 2000 may control the two-stage hydraulic press system 100 by communicating directly with the two-stage hydraulic press system 100, and / or via a server 3000.

[0104] In particular, Figure 5 shows how data, commands, and / or instructions may be exchanged between the different elements 100, 2000, 3000. The two-stage hydraulic press system 100 may here convey operational data to the server 3000 through the intermediary role of the control unit 2000. Bidirectional communication mediated by the control unit 2000 may enable remote control capabilities.

[0105] The two-stage hydraulic press system 100 may transmit operational data to the server 3000 while also receiving instructions, including commands, from the control unit and / or the server 3000.

[0106] The control unit 2000 may be designed to manage and oversee operation of the two-stage hydraulic press system 100 and its communication with the server 3000. The control unit 2000 may be a hardware device, a software-based controller, or a combination of both. The control unit 2000 may serve to coordinate the actions of the two-stage hydraulic press system 100 and / or the server 3000. The control unit 100 may ensure that data is transmitted, commands are executed, and / or that instructions are carried out by the two-stage hydraulic press system 100.

[0107] The server 3000 may be any computer or network of computers designed to receive, store, process, transmit data, and / or transmit commands. The server 3000 may be a cloud-based server or an on-premises server. The server 3000 may further manage data, analyze data, and / or exchange any suitable information with the control unit 2000 and / or the hydraulic press system 100.

[0108] Figure 6 shows a flowchart of a method 1000 for operating a two-stage hydraulic press system 100. The method 1000 may be provided by the two-stage hydraulic press system 100. The method comprises operating a first drive mode 1010 and operating a second drive mode 1020.

[0109] Operating the first drive mode 1010 comprises: opening 1100 the flow control valve 150 to disengage the second piston 122 by allowing free passage of the second fluid between the chambers 124a, 124b of the second hydraulic cylinder 120 via the flow control valve 150; driving 1200 the first servo-driven pump 130 to deliver the first fluid to the first hydraulic cylinder 110; and moving 1300, by the first piston 112, the movable pressing component 104 with the first speed.

[0110] Operating the second drive mode 1020 comprises: closing 1400 the flow control valve 150 to engage the second piston 122; driving 1500 the second servo-driven pump 140 to deliver the second fluid to the second hydraulic cylinder 120; and moving 1600, by at least the second piston 122, the movable pressing component 104 with the second speed.

[0111] It is to be understood that the method 1000 may be performed reversibly. In other words, operation of the first drive mode 1010 may be conducted after having executed the operation of the second drive mode 1020.

[0112] The step of closing 1400 the flow control valve 150 may comprise gradually closing the flow control valve 150. Moreover, the step of moving 1600 the movable pressing component 104 with the second speed may comprise driving the first servo-driven pump 130 and the second servo-driven pump 140 simultaneously, thus acting on the first and second pistons 112, 122, respectively.

[0113] In the above the inventive concept has mainly been described with reference to a number of non-limiting examples. However, as is readily appreciated by a person skilled in the art, other examples than the ones disclosed above are equally possible within the scope of the inventive concept, as defined by the appended claims.

Claims

1. A two-stage hydraulic press system (100) having a first drive mode and a second drive mode, the two-stage hydraulic press system (100) comprising: a movable pressing component (104); a first hydraulic cylinder (110) comprising a first piston (112) defining two chambers (114a, 114b) of the first hydraulic cylinder (110); a second hydraulic cylinder (120) comprising a second piston (122) defining two chambers (124a, 124b) of the second hydraulic cylinder (120); a first servo-driven pump (130) configured to deliver a first fluid to the first hydraulic cylinder (110); a second servo-driven pump (140) configured to deliver a second fluid to the second hydraulic cylinder (120); and a flow control valve (150), connected to the chambers (124a, 124b) of the second hydraulic cylinder (120), configured to engage and disengage the second piston (122), wherein the first piston (112) and the second piston (122) are mechanically interconnected and configured to in unison induce a movement of the movable pressing component (104); wherein, in the first drive mode, the second piston (122) is configured to be disengaged and at least the first servo-driven pump (130) is configured to induce a movement of the movable pressing component (104) with a first speed; and wherein, in the second drive mode, the second piston (122) is configured to be engaged and at least the second servo-driven pump (140) is configured to induce a movement of the movable pressing component (104) with a second speed.

2. The two-stage hydraulic press system (100) according to claim 1 further comprising: a first and second hydraulic valve system (160, 170) configured to respectively control a fluid compression volume of the first and second fluids to and from the first and second hydraulic cylinders (110, 120).

3. The two-stage hydraulic press system (100) according to claim 1 or 2, wherein the first speed is larger than the second speed.

4. The two-stage hydraulic press system (100) according to any one of the preceding claims, wherein the first drive mode corresponds to a high-speed low-force movement of the movable pressing component (104), and the second drive mode corresponds to a high-force low-speed movement of the movable pressing component (104).

5. The two-stage hydraulic press system (100) according to any one of the preceding claims, wherein the second piston (122) is configured to be: disengaged when the flow control valve (150) is in an open state, allowing for the second fluid to flow between the chambers (124a, 124b) of the second hydraulic cylinder (120) via the flow control valve (150), and the first and second pistons (112, 122) to move with low resistance; and engaged when the flow control valve (150) is in a closed state.

6. The two-stage hydraulic press system (100) according to any one of the preceding claims, wherein the two-stage hydraulic press system (100) comprises a first and second closed hydraulic circuit (101, 102).

7. The two-stage hydraulic press system (100) according to any one of the preceding claims, wherein the movement of the movable pressing component (104) in the second drive mode is configured to be induced by the first servo-driven pump (130) and the second servo-driven pump (140) acting on the first and second pistons (112, 122), respectively.

8. The two-stage hydraulic press system according to any one of the preceding claims, wherein the first servo-driven pump (130) is driven by a first servomotor (132), and the second servo-driven pump (140) is driven by a second servomotor (132).

9. The two-stage hydraulic press system (100) according to any one of the preceding claims, wherein the first servo-driven pump (130) is a first plurality of servo-driven pumps (130), and / or the second servo-driven pump (140) is a second plurality of servo-driven pumps (140).

10. The two-stage hydraulic press system (100) according to claim 9, wherein the first plurality of servo-driven pumps (130) is driven by a first plurality of servomotors (132), and / or the second plurality of servo-driven pumps (140) is driven by a second plurality of servomotors (142).

11. The two-stage hydraulic press system (100) according to any one of the preceding claims, wherein the second servo-driven pump (140) is configured to be controlled at a rotational speed corresponding to the second speed in the second drive mode.

12. A method (1000) for operating a two-stage hydraulic press system according to any one of the preceding claims, the method (1000) comprising operating a first drive mode (1010) and a second drive mode (1020), operating the first drive mode (1010) comprising: opening (1100) the flow control valve to disengage the second piston by allowing free passage of the second fluid between the chambers of the second hydraulic cylinder via the flow control valve; driving (1200) the first servo-driven pump to deliver the first fluid to the first hydraulic cylinder; and moving (1300), by the first piston, the movable pressing component with the first speed, and operating the second drive mode (1020) comprising: closing (1400) the flow control valve to engage the second piston; driving (1500) the second servo-driven pump to deliver the second fluid to the second hydraulic cylinder; and moving (1600), by at least the second piston, the movable pressing component with the second speed.

13. The method according to claim 12, wherein the step of moving (1600) the movable pressing component with the second speed comprises driving the first servo-driven pump and the second servo-driven pump simultaneously, acting on the first and second pistons, respectively.

14. The method according to claim 12 or 13, wherein closing (1400) the flow control valve comprises gradually closing the flow control valve.

15. A control unit (2000) configured to perform the steps of the method (1000) according to any one of claims 12-14.

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