EP2183096A1 - Système d'entraînement pour presses hydrauliques - Google Patents

Système d'entraînement pour presses hydrauliques

Info

Publication number
EP2183096A1
EP2183096A1 EP08801211A EP08801211A EP2183096A1 EP 2183096 A1 EP2183096 A1 EP 2183096A1 EP 08801211 A EP08801211 A EP 08801211A EP 08801211 A EP08801211 A EP 08801211A EP 2183096 A1 EP2183096 A1 EP 2183096A1
Authority
EP
European Patent Office
Prior art keywords
force
counter
plunger
pressure
holding
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Withdrawn
Application number
EP08801211A
Other languages
German (de)
English (en)
Inventor
Christian Wieber
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Individual
Original Assignee
Individual
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Individual filed Critical Individual
Publication of EP2183096A1 publication Critical patent/EP2183096A1/fr
Withdrawn legal-status Critical Current

Links

Classifications

    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B30—PRESSES
    • B30B—PRESSES IN GENERAL
    • B30B15/00—Details of, or accessories for, presses; Auxiliary measures in connection with pressing
    • B30B15/16—Control arrangements for fluid-driven presses
    • B30B15/24—Control arrangements for fluid-driven presses controlling the movement of a plurality of actuating members to maintain parallel movement of the platen or press beam
    • B30B15/245—Control arrangements for fluid-driven presses controlling the movement of a plurality of actuating members to maintain parallel movement of the platen or press beam using auxiliary cylinder and piston means as actuating members
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B30—PRESSES
    • B30B—PRESSES IN GENERAL
    • B30B15/00—Details of, or accessories for, presses; Auxiliary measures in connection with pressing
    • B30B15/16—Control arrangements for fluid-driven presses
    • B30B15/24—Control arrangements for fluid-driven presses controlling the movement of a plurality of actuating members to maintain parallel movement of the platen or press beam
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F15—FLUID-PRESSURE ACTUATORS; HYDRAULICS OR PNEUMATICS IN GENERAL
    • F15B—SYSTEMS ACTING BY MEANS OF FLUIDS IN GENERAL; FLUID-PRESSURE ACTUATORS, e.g. SERVOMOTORS; DETAILS OF FLUID-PRESSURE SYSTEMS, NOT OTHERWISE PROVIDED FOR
    • F15B11/00—Servomotor systems without provision for follow-up action; Circuits therefor
    • F15B11/16—Servomotor systems without provision for follow-up action; Circuits therefor with two or more servomotors
    • F15B11/22—Synchronisation of the movement of two or more servomotors
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F15—FLUID-PRESSURE ACTUATORS; HYDRAULICS OR PNEUMATICS IN GENERAL
    • F15B—SYSTEMS ACTING BY MEANS OF FLUIDS IN GENERAL; FLUID-PRESSURE ACTUATORS, e.g. SERVOMOTORS; DETAILS OF FLUID-PRESSURE SYSTEMS, NOT OTHERWISE PROVIDED FOR
    • F15B2211/00—Circuits for servomotor systems
    • F15B2211/70—Output members, e.g. hydraulic motors or cylinders or control therefor
    • F15B2211/71—Multiple output members, e.g. multiple hydraulic motors or cylinders
    • F15B2211/7114—Multiple output members, e.g. multiple hydraulic motors or cylinders with direct connection between the chambers of different actuators

Definitions

  • the invention relates to a drive system for hydraulic presses. These are versatile because of their usually large working stroke and the forming force available throughout the stroke, but also have a number of disadvantages. For example, presses are used with a large stroke for forming tasks that require only a short stroke, such as cutting or punching, so make the compressibility of the hydraulic fluid and the elastic deformation of the press frame negative impact, which must be required to build up the required forming force additionally required pressure fluid volume provided by the pump, thus increasing the cycle time.
  • a parallel control device is further known in the Schmidthaltezlinder are connected to the pressure chambers of two rigidly connected Gleichgangzylinder, whereby in this way in conjunction with a servo valve, a parallel movement of the plunger is achieved.
  • this device ensures no constant bias of the press frame, both when used on mechanical presses and on hydraulic presses thus subject to the press frame during the stroke elastic deformations.
  • the invention is based on the object to provide a drive system for hydraulic presses, which allows independent of the particular forming force constant bias of the press frame and thus precise guidance of the plunger, independent of the respective forming force high efficiency especially for short strokes offers , a force-neutral parallel control allows a high eccentric loading of the plunger allows, and in addition has a significantly reduced cutting energy.
  • a drive system presses offer compared to prior art hydraulic presses thus a universal applicability for a variety of forming processes, reduced wear and good accessibility of the tools, reduced energy consumption and increased output, especially in short-stroke forming processes. It can be dispensed with a particularly rigid design of the press frame, which in addition material can be saved.
  • the effective direction of which is opposite to the closing force acting on the ram.
  • the transmission of the counter-holding forces on the plunger can be done, for example, by corresponding pressure-resistant force-transmitting components that allow easy replacement or by force and / or positive-acting adjustment adjustment to the respective tool installation height, by acting directly on the plunger piston rods of the counter-holding cylinder or, in the event that the counter-holding cylinders are an integral part of the tool, through the upper tool connected to them.
  • the drive system according to the invention has at least one hydraulic coupling device, which has two pressure chambers which are separated from one another as free of leakage as possible, at least by a movable separating element.
  • the hydraulic coupling device has at least one device for introducing an external force, which allows a transmission of this force to the movable separating elements or the.
  • a pressure chamber of the hydraulic coupling device is connected to the pressurized space or chambers of the ram cylinder subjected to constant pressure, while the other pressure chamber is connected to the pressure space or chambers of the counter-holding cylinder or cylinders.
  • Pressure chambers prevailing pressures thus act two forces or force components on the one or more separators, and thus also on the associated device for introducing an external force.
  • the respective pressure chambers do not necessarily have to be directly connected with each other here, this connection can also be indirectly, e.g. via additional pressure booster.
  • additional pressure booster can e.g. be advantageous if the counter-holding cylinders are an integral part of the tool and they are to be operated to reduce the size of a higher pressure than the plunger cylinder, the pressure booster allow this the use of hydraulic coupling devices in which the movable separating element has the same effective areas for both pressure chambers.
  • the press if necessary, initially closed so far until the plunger rests on the piston rods or other components of the counter-holding cylinder, which may be made by appropriate means a mechanical and / or hydraulic adjustment to the installation height of the tool can. Subsequently, the pressure build-up takes place in the ram circle, whereby this pressure is kept constant or at least approximately constant by corresponding devices during a complete stroke as well as over several successive strokes.
  • the closing force generated thereby by the plunger cylinder now also acts on the pistons of the counter-holding cylinder, neglecting friction, gravitational and deformation forces and with the same active surfaces of the pressure in the ram circle thus generates an equal pressure in the counter-holding cylinders.
  • the movable separating element has the same size effective areas in both pressure chambers and the effective areas of ram cylinder and counter-holding cylinders are also the same size is, apart from the pressure differences in the Counter-holding cylinders caused volume changes, the plunger circuit neither removed nor supplied pressurized fluid, whereby the design of the means for keeping constant the pressure in the ram circle simplified accordingly.
  • Fig. 1 shows an embodiment of the drive system in which the required force is hydraulically generated on the movable separating elements and which enables a force-neutral parallel control of the plunger;
  • Fig. 2 shows an exemplary embodiment of the drive system in which the force required on the movable separating elements is mechanically and / or hydraulically generated and in which the plunger movement can be effected by the superposition of the movements of multiple drives;
  • Fig. 3 shows an embodiment of the drive system in which the required force is hydraulically generated on the movable separating elements, the press is used for deep drawing in return method and while the force introduced by the drawing punch in the plunger force can be at least partially compensated by the movable separating elements;
  • Fig. 4 shows an embodiment of the drive system which is designed for large working strokes and also allows fast closing and opening movements of the plunger without the need for movement of the movable separating elements is required;
  • Fig. 5 shows an embodiment of the drive system which is very efficient especially in the operation of cutting tools and also can easily be retrofitted to existing, single or multiple acting conventional hydraulic presses.
  • the illustrated in Fig. 1 hydraulic press consists of a press frame 1, a movably guided in this plunger 2 and connected to this, located in the press main double-acting plunger cylinder 6, the forces required for the closing and ⁇ ffhungsterrorism and the forming operation in conventional operation generated and introduced into the plunger 2, while the control of the plunger cylinder 6 via a conventional hydraulic press control 7 in conjunction with a main pump 8, this control is shown here greatly simplified.
  • the press shown here is basically also suitable for forming processes with a long forming path, such as thermoforming, the here usually on universally applicable hydraulic presses existing auxiliary equipment such as pulling device, ejector, etc. are not shown here for reasons of clarity.
  • the plunger 2 is first lowered by means of the conventional press control 7 until it is supported by the force-transmitting components 10 on the piston rods of the counter-holding cylinders 9, wherein these are here in the press bed and their piston rods by appropriate Cutouts in the press table 3 protrude.
  • An adaptation to different mounting heights of the forming tools 4 can be done here, for example, by simple replacement or force and / or positive acting adjustment of the force-transmitting components 10, corresponding devices are known, for example, for adjusting the cutting impact damping from conventional press construction.
  • these hydraulic coupling devices 17 consist of two flanged-parallel cylinders, which are connected via a common piston rod rigidly interconnected pistons same annular surfaces here as movable separating elements 18a, 18b, further serves the common piston rod as a device for the introduction of an external force 19c on the separating elements 18th
  • the generation of external force on the movable separating elements 18 by a hydraulic drive cylinder 20 this is carried out here as Differentialzy cylinder and flanged directly to the two coupling devices 17 a, 17 b, resulting from the use of the common piston rod 19 c thus an advantageous, extremely compact and stiff drive unit.
  • the control of the drive cylinder 20 via the control valve 21, the pressure fluid flow required for this is provided in the embodiment shown here by the already existing for the conventional operation of the press main pump 8
  • the gravitational force acts on the plunger 2 in the illustrated here upper piston press, this is additionally introduced via the force-transmitting components 10 in the counter-holding cylinder 9, whereby the pressure in the counter-holding cylinders 9 by a certain amount the pressure in the ram 13 increases.
  • the pressures in the counter-holding cylinder 9 now act respectively on the left sides of the two pistons 18a, 18b, while the pressure in the ram circle 13 acts on the right sides.
  • the pressure fluid volumes removed by the movement of the movable separating elements 18 from the counter-holding cylinders 9 and supplied to the ram circle 13 correspond exactly to the product of the respectively connected active surfaces and this stroke, with the given design of the active surfaces of the ram cylinder 6, counter-holding cylinders 9 and movable Separating elements 18 is the pressure accumulator 16 thus removed at constant pressures neither pressure fluid nor supplied. If a force acting in the direction dl is exerted on the common piston rod 19c by corresponding activation of the control valve 21 by the drive cylinder 20, this force leads to an increase in volume and thus to a relaxation or pressure reduction of the pressure fluid in the counter-holding cylinders 9, the pressure accumulator 16 takes while the the the pressure accumulator 16
  • Plunger circuit supplied pressure fluid quantity and thus keeps the pressure in the ram circuit 13 at least approximately constant.
  • the height of the pressure difference depends on the active surfaces of the piston 18 and the force introduced by the drive cylinder 20, while the force exerted on the forming tool 4 and thus on the workpiece S force of the difference between the closing force and counter-holding force and thus the product of the generated pressure difference and the active surfaces of the counter-holding cylinder 9 depends. If the force exerted on the workpiece 5 now exceeds the required forming force, the force generated by the drive cylinder 20 shifts the common piston rod 19c further in the direction d1, and the plunger 2 carries out the working stroke.
  • the force exerted on the forming tool 4 and thus on the workpiece 5 in this case depends only on the hydraulic mechanismsssens and the force introduced into the movable separating elements 18 force, a regulation and limitation of the force exerted on the workpiece 5 force can thus via a corresponding control of Forces of the drive cylinder 20 take place, the pressure in the ram circle 13 and thus the closing force generated by the plunger cylinder 6 has no influence and can thus be kept at a constant, at least sufficiently high value for the forming process, causing the
  • Another significant advantage of the embodiment shown here is the use of two hydraulic coupling devices 17a, 17b with rigid coupling and common drive 20 for generating the external force and the separate assignment of a group of counter-holding cylinders 9a, 9b to each of these hydraulic coupling devices 17, this arrangement ensures a largely parallel closing of the plunger 2 during the forming process.
  • the forming tool 4 for example, a composite tool, while one-sided is driven to block, gravitational and frictional forces are neglected.
  • the force to be applied by the drive cylinder 20 regardless of the degree of off-center loading, continues to be proportional to the actual forming force required.
  • the forming force to be applied by the counter-holding cylinders 9a is 50% and that of the
  • Counteracting cylinders 9b applied forming force 0% of the press nominal force, so the force acting on the movable partition member 18a pressure difference reaches its maximum value, while the acting on the movable partition member 18b pressure difference is zero.
  • the applied by the drive cylinder 20 and introduced into the common piston rod 19c force is thus also only 50% of the force required to generate the press rating, resulting in optimum efficiency.
  • the compensation cylinder 25 here consists of two piston rod side fixedly interconnected differential cylinders with a common piston rod 25b, the two sealed annular spaces are each connected to a group of Gegenhaltezylindern 9a, 9b, while the two piston-side connections are guided to the corresponding terminals 26 of the control valve , If an off-center load now leads to different pressures in the groups of counter-holding cylinders 9a, 9b, the resulting different compression of the
  • the control electronics detects this ram tilting and compensates for the difference in volume caused by the pressure difference by a corresponding displacement of the piston 25a connected via the common piston rod 25b of the compensation cylinder 25.
  • Decreases due to off-center loading e.g. the pressure in the two left counter-holding cylinders 9a, there is a displacement of the piston 25a in direction d2 the two right Jacobhaltezylindern 9b is thus supplied to a certain pressure fluid volume, while the two left Jacobhaltezylindern 9a at the same time a corresponding amount is removed, by the different pressure In the two groups of counter-holding cylinders 9a, 9b caused plunger tilt is thus compensated.
  • the active parallel control must compensate only in the groups of counter-holding cylinders 9a, 9b and the associated pressure chambers caused by compression or decompression volume changes, with correspondingly low pressure fluid volumes thus only small compensation volumes are needed, creating a highly dynamic control is possible.
  • the pressure fluid supply for the control valve 26 takes place in the embodiment shown here from the ram 13, by the large compression volume and the already existing pressure accumulator 16 this supports the dynamics of the control process, the feed pump 14 in this case consumes the consumed during the control process pressure fluid to the ram circuit 13 again ,
  • both the passive and the active parallel control can act in more than one plane.
  • the pressure fluid volumes present in the counter-holding cylinders 9 and the associated pressure chambers are reduced to a minimum, since a shorter cycle time and higher efficiency are achieved due to the reduced compression volumes. In the embodiment shown here, this is done by the common
  • Piston rod 19 is first moved through the drive cylinder 20 until it stops in direction d2. After opening the check valves 24, the pressure fluid present in the counter-holding cylinders 9 is now displaced into the tank by the force acting on the plunger 2 gravitational force or the spring return, until the pistons are at the bottom stop. Will now, with still open check valves 24, the common
  • Piston rod 19 as far as in the direction dl process by the drive cylinder 20, as is required for each required ram stroke, the required pressure fluid is sucked through the open check valves 24 from the tank, after closing the check valves 24 is thus a defined, for the required ram stroke just sufficient amount of pressure fluid in the counter-holding cylinders 9 and the associated pressure chambers.
  • the required e.g. located on the drive cylinder 20 displacement sensor and the corresponding control device for controlling the control valve 21 are not shown here for reasons of clarity. Any necessary adaptation to different tool installation heights can be done by replacing or adjusting the force-transmitting components 10. It is also understood that the pressure fluid volumes in the pressure medium lines between the counter-holding cylinders 9 and the hydraulic coupling devices 17 should also be reduced to a minimum.
  • the drive cylinder 20 can continue to be used for a controlled reduction of the cutting impact energy. Is brought as soon as possible after the material has broken off, for example, by corresponding, not shown, or acceleration sensors, the control valve 21 for the drive cylinder 20 in the locked center position, then increases as the displacement of the common piston rod 19 in the direction dl the pressure on the annulus side of Drive cylinder 20 except for the pressure set on the pressure relief valve 22, while at the same time the pressure drops on the piston side.
  • the common housing of the two hydraulic coupling devices 17a, 17b is supported here also on the piston rod 29a of a double-acting, also fixedly mounted and here designed as a differential cylinder force limiting cylinder 29, whereby a common piston rod 19c axial displacement of the hydraulic coupling devices 17 is made possible.
  • Piston rod 19c is now transmitted by the two associated movable separating elements 18 on the counter-holding cylinder 9 and thus on the plunger 2, the path-time diagram of the plunger movement, the energy available per stroke and the dependent on the position of the eccentric 28a on the plunger. 2 available power thus largely correspond to a mechanical eccentric press.
  • a favorable ratio between the force generated by the eccentric 28 and the plunger 2 available force can be achieved in this case, designed for the case of the eccentric 28 for a large stroke at relatively small forces this can be designed according to cost Nevertheless, the hydraulic transmission ratio still allows a high forming force at a correspondingly shorter ram stroke.
  • the force limiting cylinder 29 serves in this case.
  • the annular space side is connected to the tank, to limit the force this is thus operated here as a single-acting cylinder.
  • the force introduced via the connecting rod 28c into the common piston rod 19c of the two hydraulic coupling devices 17a, 17b also acts on the common housing and, via the piston rod 29a connected thereto, on the pressure differences caused thereby at the movable separating elements 18a, 18b Piston of the force limiting cylinder 29. If this force exceeds the product of the piston surface and the pressure set on the pressure limiting valve 30, then the piston displaces the hydraulic fluid contained therein, and the piston rod 29a moves in the direction dl.
  • the effect of the force limit can also be used particularly advantageous for certain forming processes, such as a displacement of the bottom dead center in the direction of the closed forming tool 4 can be achieved when embossing by adapting the force-transmitting components 10, thereby in the eccentric drive 28 shown here, the forming tool 4 are kept closed for a determinable time with a constant force. If in this case the piston side of the force limiting cylinder 29 connected to a corresponding biased pressure accumulator, not shown, the force applied during the closing phase by the eccentric 28 energy for displacement of the piston rod 29a in the direction dl this can be supplied again during the opening phase. Except by the force limiting cylinder 29 shown here, the limit of the
  • Eccentric drive 28 in the hydraulic coupling devices 17 introduced force also carried elsewhere, e.g. by mechanical friction clutches.
  • the press can thus be used for example during operation on the conventional press control 7 for deep drawing, while in operation by means of the drive system according to the invention the ram drive either via the eccentric 28 with additional force limit, the eccentric 28 with superimposed movement of the actively operated force limiting cylinder 29 or, by setting the eccentric 28a, for example in the 180 ° position, can be done only on the actively operated force limiting cylinder 29.
  • the stroke rate, stroke, ram kinematics as well as the force available on the plunger 2 can thus be optimally adapted to the particular forming task and enable maximum output with simultaneously high efficiency.
  • the required external force can also be introduced by other known from the mechanical press construction types of drive in the movable separating elements 18, for example by Articulated drives, toggle or modified toggle drives, etc., whereby the kinematics of the plunger movement can be optimized for the respective forming task.
  • Another advantage of the drive system according to the invention can be achieved in that the ratio of the active surfaces between plunger cylinder 6 and counter-holding cylinders 9 is changed.
  • the gravitational force in addition to the closing force, the gravitational force also acts on the plunger 2 and thus on the counter-holding cylinders 9, which leads to an increase in pressure in the pressure chambers of the counter-holding cylinders 9.
  • this leads to a force in the direction d 1 on the common piston rod 19 c, which was used there for rapid closing of the tappet 2 in the case of corresponding area ratios.
  • FIG. 3 illustrates a further advantageous embodiment of the drive system according to the invention.
  • This press shown here is equipped with a forming tool 4 for the combined cutting-train process, the drawing die 4c serves as a cutting punch, while the lower die 4a the function of cutting die and Sheet holder takes over. in the
  • Press bed is the drawing device 33, which is shown here as a differential cylinder, which is connected via the piston rod with the drawing punch 34, the control via the associated directional control valve 35, the auxiliary devices shown in the other embodiments, such as active parallel control 25, 26, check valves 24 for the counter-holding cylinder 9, etc. are not shown here for reasons of clarity, but an additional hydraulic device for cutting impact damping, consisting of the two creeper valves 37 for flow limitation and the associated pressure relief valves 38. In the off state, the creep valves 37 allow free flow in both Directions and have no influence on the operation. But if these, e.g.
  • valves 37, 38 should be connected via the shortest possible pressure medium lines with the counter-holding cylinders 9, preferably therefore each counter-holding cylinder 9 own valves 37, 38 are assigned, the pressure build-up in the counter-holding cylinders 9 and thus the delay of the plunger 2 thus happens almost immediately after the material is broken.
  • this type of cutting shock damping if after cutting further forming operations are to take place, such as here the deep drawing.
  • the piston-side pressure chamber of the pulling device 33 is connected to the annulus of the device for compensating the punching force 36, this is designed as a differential cylinder wherein the piston 36a is connected to the common piston rod 19c of the hydraulic coupling devices 17, the piston-side pressure chamber the device for compensating the punching force 36 is connected to the surrounding atmosphere and can therefore be neglected in terms of power.
  • the cutting operation by means of the counter-holding cylinders 9 has already taken place, the cut-out blank 5a is located between the drawing die 4c and the lower tool 4b serving as a blank holder.
  • the pistons 18a, 18b, 36a have the same annular surfaces, the sum of the active surfaces of the counter-holding cylinders 9 in the counter-holding direction equal to the effective area of the plunger cylinder 6 in the closing direction, as well as the effective surface of the pulling device 33 in the drawing direction equal Half of the effective surface of the plunger cylinder 6 in the closing direction.
  • This pressure now also acts on the annular surface of the Piston 36a and thus generates in the common piston rod 19c a force in the direction dl which, in still missing introduction of an external force, a pressure drop in the counter-holding cylinder 9 and thus a reduction in the Holding force causes.
  • the pressure in the pulling device 33 caused by the drawing process increases, for example, to the value of the pressure in the ram circle 13, the pressure in the counter-holding cylinders 9 drops to half the pressure in the ram circle 13 at the given active surfaces, as a result of which the counter-holding force is exactly equal to that of the drawing device 33 generated stamping force is reduced.
  • the force introduced by the pulling device 33 in the plunger 2 force can be compensated by the force on the piston 36 a.
  • This can also be achieved, for example, by enlarging the annular surface of the piston 36a, that the reduction in the counter-holding force caused by the pressure in the pulling device 33 is greater than the stamping force generated by the pulling device, characterized practicing the plunger 2 during the drawing process additionally one of Stamping force proportional sheet holding force on the blank 5a, without the introduction of an external force by the drive cylinder 20 is required here.
  • the active parallel control 25, 26 shown in the exemplary embodiment according to FIG. 1 is furthermore used, this can be used to specifically change the pressures and thus the sheet holding forces in the individual groups of counter-holding cylinders 9a, 9b and thus, for example, the deep-drawing of asymmetrical To enable sharing. Due to the small compression volumes, rapid pressure changes are possible with small volume flows.
  • the press shown here can thus, with a suitable design of the hydraulic control 35 for the pulling device 33 and the stroke of the ram cylinder 6, both for conventional deep drawing me passive die cushion, deep drawing inelleszugvon with active die cushion, deep drawing in the cutting-train process , as well as for the operation of cutting, punching, compounding, progressive tools, etc., ensuring in all applications high efficiency, high output and high flexibility in terms of permissible installation heights and good accessibility of the forming tools 4.
  • Fig. 4 shows an embodiment of the drive system according to the invention, which is also suitable for large forming paths and in which fast closing and / or opening movements of the plunger 2 can be done without the movement of the movable separating elements 18 is required for this purpose.
  • the generation of the external force, in this case a torque is effected here by two electric motors 39, wherein each motor is associated with a respective hydraulic coupling device 17a, 17b.
  • the two coupling devices 17a, 17b exist here from two adjustable axial piston pumps for the closed circuit, the volume flow and conveying direction can be controlled by a corresponding adjustment.
  • the movable separating elements 18 thus consist of the piston of the axial pump engines, not shown here, the introduction of external force on the separating elements via the introduced into the drive shafts 19 a, 19 b torque in conjunction with the swash plates, shoes, etc. also not shown here
  • the differential check valve 11 instead, this embodiment has a proportional control valve 40 for controlling the fast closing and opening movements, which takes place here via the annulus side of the plunger cylinder 6.
  • this embodiment has two lock-up valves for the hydraulic coupling devices 42 which produce a direct connection between the ram circle 13 and the counter-holding cylinders 9 in the controlled state, and two pressure relief valves 41, which the maximum difference between the pressure in the ram circle 13 and the pressure in the Limit counter-holding cylinders 9.
  • section I shows the press in a wide open condition, as may be required for insertion or transfer operations.
  • the lock-up valve 42 is opened here, whereby the pressure fluid between the ram circle 13 and the counter-holding cylinders 9 regardless of the hydraulic
  • Coupling devices 17 can be freely exchanged. At the same area ratios of plunger cylinder 6 and counter-holding cylinders 9, the forces generated by them are in equilibrium, which in addition to the plunger 2 and the parts connected to it such as upper tool 4a and piston rod and piston of the plunger cylinder 6 acting gravitational force generated at locked control valve 40, a pressure increase in the annular space of the plunger cylinder 6, the plunger 2 is thereby held in the open position.
  • Pressure limiting valves 41 here two functions. On the one hand they limit the maximum pressure difference between ram circle 13 and counter-holding cylinders 9 and thus, regardless of the pressure in the ram circle 13, the maximum forming force, on the other hand they prevent cavitation in the axial piston pumps used here as hydraulic coupling 17 cavitation due to a low pressure in the counter-holding cylinders 9 occurs.
  • the opening of the press can be done in two ways. If greater forces are required for opening, e.g. due to existing Abstreifin, first, the conveying direction of the hydraulic coupling devices 17 can be reversed, the opening force is generated by the resulting pressure increase in the counter-holding cylinders 9, after the stripping operation then the lock-up valves 42 are opened again and the rapid opening stroke takes place by the pressurization of the annulus side the plunger cylinder 6 via the control valve 40, the hydraulic fluid is thereby circulated again by the plunger cylinder 6 via the lock-up valves 42 in the counter-holding cylinder 9.
  • the rapid opening movement can be initiated directly by opening the lock-up valves 42 and pressurizing the annular space side of the ram cylinder 6, in which case a reversal of the conveying direction of the hydraulic coupling devices 17 is not required.
  • the hydraulic coupling devices 17a, 17b can thus be positioned closer to the respective counter-holding cylinder or the groups of counter-holding cylinders 9a, 9b, which a further reduction of the compression volume leads.
  • the maximum available replacement volume of the hydraulic coupling devices 17 is not limited by the mechanical dimensions of the coupling devices, as e.g. when using hydraulic cylinders is the case. This allows a correspondingly compact construction of the hydraulic coupling devices 17, in particular for large forming paths, a conventional press control 7 can therefore be omitted in this embodiment, even when used for forming operations with a long stroke.
  • Volumetric flow and conveying direction can be controlled by appropriate control of the servo motors and these can be used simultaneously for the compensation of leaks between the two pressure chambers of the hydraulic coupling device 17. Furthermore, there is the possibility, as already mentioned in the description of Fig.2, by appropriate Changing the area ratios between the plunger cylinder 6 and the counter-holding cylinders 9 to vary the forces generated thereby.
  • Fig. 5 shows a further embodiment of the drive system according to the invention, which has a very high efficiency, especially when using cutting tools.
  • the hydraulic coupling device 17 here consists of two stationary mounted single-acting differential cylinders, serving as movable separating elements piston 18a, 18b are firmly connected to each other by means of the piston rod 19.
  • the generation of the external force is done here by a likewise fixedly mounted and designed as a servo motor electric drive 45, wherein the torque generated by it is introduced here via the pinion in the toothing serving here as means for introducing an external force piston rod 19 and so on corresponding force in the movable separating elements, that is, the two pistons 18a, 18b, is introduced, the limitation of the maximum forming force can thus be effected by a corresponding limitation of the torque of the servomotor 45.
  • the generation and transmission of the force can of course be done differently, for example by means of a torque motor in conjunction with a ball screw and a corresponding nut. As in the embodiment of FIG.
  • the movable dividing elements 18 are here only on one side pressurized, the force balance is in this case via the piston rod 19.
  • the two of the pistons 18a, 18b generated and acting on the piston rod 19 forces cancel each other at different effective surfaces of plunger cylinder 6 and counter-holding cylinders 9 and the associated different pressures at the same closing and Jacobhalte practitionern, an additional pressure booster is not needed in this case.
  • the counter-holding cylinders 9 are in this embodiment an integral part of the tool, so are located between the upper tool 4a and lower tool 4b, preferably here again four counter-holding cylinder 9 to install in the corner regions of the tool.
  • the passive parallel control is also omitted in this exemplary embodiment. Furthermore, there are in the pressure lines between the coupling device 17 and those associated with their counter-holding cylinders 9 each a burst safety valve 46 and, in parallel, depending a pilot-operated check valve 47, only two counter-holding cylinder 9 and two respective valves 46, 47 shown due to the section here ,
  • the burst safety valves 46 are set so that they just do not trigger at the desired forming speed, they can be bridged by controlling the pilot-operated check valves 47, which allows a fast closing of the tool 4 without a premature response of the pipe safety valves 46.
  • the valves 46, 47 are to be arranged as close as possible to the respective counter-holding cylinders 9 in order to reduce the incipient cutting energy.
  • the press is just at the beginning of Umformhubes, the pilot-operated check valves 47 are closed, the servo motor 45 rotates clockwise, thus generating a force on the piston rod 19, which moves the two movable separating elements 18a, 18b in the direction d2 , The counter-holding cylinders 9 is thereby removed via the still open pipe safety valves 46 pressure fluid, the pressure difference thus generated reaches a sufficient value of the associated with the upper tool 4a cutting punch in the material. In the course of the cutting process, the material is now torn off, due to the force difference acting on the tappet 2, it is abruptly accelerated and the cutting stroke takes place.
  • the maximum pressure occurring in the counter-holding cylinders 9 depends mainly on the pressure in the ram circle 13, the pressure difference required between the pressure in the ram circle 13 and the pressure in the counter-holding cylinders 9 and the response speed of the burst safety valves 46 to generate the forming force. In unfavorable cases, the occurring maximum pressure can exceed the operating pressure of the components acted upon therewith, that is to say counter-holding cylinders 9, burst-break safety valves 46 as well as unlockable check valves 47. To avoid this in the embodiment shown here each counter-holding cylinder 9 is assigned a respective differential cylinder 48, due to the sectional view here again only two differential cylinders 48 are shown.
  • the pistons of the differential cylinder 48 are at the stop in the direction dl and have no influence on the operation of the inventive drive system. However, if, due to a cutting stroke, an increase in the pressure exceeds the value calculated above, the pressure fluid is displaced from the counter-holding cylinders 9 into the two differential cylinders 48, with the pistons moving in the direction d2. The occurring in the counter-holding cylinders 9 maximum pressure is thus on a limited fixed value and the plunger 2 with a constant force further delayed.
  • the combination of servo motor 45 and hydraulic coupling device 17 should be considered.
  • the servomotor 45 first initiates a force in the direction d2 via the piston rod 19 into the two movable separating elements 18a, 18b.
  • the separating element 18b in the direction d2 thus takes place a decompression of the hydraulic fluid in the right pressure chamber of the hydraulic coupling device 17 and the associated counter-holding cylinders 9, for which a corresponding energy is needed.
  • Pipe burst safety valves 46 the connection between the counter-holding cylinders 9 and the hydraulic coupling device 17 is suddenly blocked, which leads to a sudden increase in pressure in the counter-holding cylinders 9.
  • the cut cut can now be detected and the servo motor are switched off, this can be done simply via a differential pressure measurement, the pressure in the counter-holding cylinders 9 exceeds the pressure in the right pressure chamber of the hydraulic coupling device 17 by a corresponding value , this means that the pipe burst safety valves 46 are closed and thus the cutting stroke is done.
  • the drive system according to the invention can be easily retrofitted to existing single or multiple-acting presses, without the need for modification on the press frame are necessary.
  • the hydraulic transmission ratio between the movable separating elements 18 and the counter-holding cylinders 9 is advantageous, whereby e.g. acting on the movable separating elements 18 small forces at a large stroke can produce a large forming force at a correspondingly small stroke.
  • the transfer of external force to the movable dividers 18 can not only be mechanical but also otherwise, e.g. magnetic or electromagnetic.
  • the volume changes required for the plunger movement in the pressure chambers connected to the hydraulic coupling device 17 can also be achieved by an elastic deformation of the separating element 18, e.g. a pressure-resistant membrane can be achieved.
  • Counter-holding cylinders can be dispensed with the accumulator 16.
  • the erf ⁇ ndungshiele drive system could in the presence of several plunger cylinder 6 also have a plurality of ram circuits 13, each ram circuit 13 with its own hydraulic Coupling device 17 could be connected.
  • this has the disadvantage over the parallel connection of the plunger cylinders 6, which would also require a plurality of pressure accumulators 16.
  • the drive system according to the invention can also be operated instead of liquids with other pressure means, e.g. with gases or gas mixtures.
  • a particularly advantageous embodiment results here, when the drive of the plunger cylinder 6 is pneumatic, which is in the counter-holding cylinders 9 and the associated pressure chambers pressure fluid is a liquid, and the generation of external force for the drive system according to the invention by a mechanical drive 28 according to In Fig. 2 illustrated embodiment takes place.
  • the plunger cylinder 6 is thus a large travel for the plunger 2 available, resulting in a good accessibility of the forming tools 4 and a large range for the allowable installation height.
  • the ram drive can be done alone by the mechanical drive 28 without this pneumatic valves are necessary, a hydraulic pump 8, 14 is also not needed. Due to the low compressibility of the hydraulic fluid in the counter-holding cylinders 9 and the associated pressure chambers, the press operates in a highly efficient manner and can be operated with high stroke rates. Furthermore, the passive parallel control described in the exemplary embodiment according to FIG.

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  • Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • Physics & Mathematics (AREA)
  • Fluid Mechanics (AREA)
  • General Engineering & Computer Science (AREA)
  • Control Of Presses (AREA)
  • Press Drives And Press Lines (AREA)

Abstract

Système d'entraînement pour presses hydrauliques, permettant une précontrainte du bâti (1) symétrique, constante et indépendante de la force de déformation nécessaire et, par conséquent, un guidage précis du coulisseau (2), l'entraînement (20) ne devant développer que l'énergie réellement nécessaire pour le processus de déformation. Le couplage (19c) rigide de plusieurs éléments de séparation (18a, 18b) mobiles à un entraînement (20) commun permet, lorsque les cylindres de maintien antagonistes (9a, 9b) sont associés aux dispositifs de couplage hydrauliques (17a, 17b), d'obtenir un réglage parallèle passif et neutre du coulisseau (2), ce qui se traduit, d'une part, par une limitation du basculement du coulisseau maximal lorsque la charge est excentrée et, d'autre part, par une proportionnalité entre la force développée par l'entraînement (20) et la force de déformation réellement nécessaire. A cette force peut se superposer, en cas de contraintes accrues imposées au parallélisme du coulisseau (2), une régulation parallèle (25, 26) active qui présente une dynamique élevée, vu les faibles débits volumiques. La précontrainte constante du bâti (1) pendant toute la course de la presse permet de réduire les déformations élastiques à un minimum. En outre, la pression dans le piston du coulisseau (6) étant constante, le volume de liquide de pression contenu n'influe ni sur l'efficacité ni sur les cycles. Les volumes de liquides de pression contenus dans les cylindres de maintien antagonistes (9a, 9b) et dans les espaces de pression directement reliés étant réduits à un minimum, l'efficacité est élevée et les cycles sont courts, notamment lorsque les courses sont réduites, et l'énergie de la force de coupe est faible lors d'opérations de coupe et d'estampage.
EP08801211A 2007-08-24 2008-08-21 Système d'entraînement pour presses hydrauliques Withdrawn EP2183096A1 (fr)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
DE200710040286 DE102007040286A1 (de) 2007-08-24 2007-08-24 Hydraulische Presse
PCT/DE2008/001388 WO2009026893A1 (fr) 2007-08-24 2008-08-21 Système d'entraînement pour presses hydrauliques

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EP2183096A1 true EP2183096A1 (fr) 2010-05-12

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ITVI20090286A1 (it) * 2009-11-27 2011-05-28 Omera S R L Metodo di lavorazione di componenti idraulici per mezzo di una pressa idraulica e pressa idraulica per l'esecuzione di detto metodo di lavorazione.
EP2492027B1 (fr) * 2011-02-23 2014-06-25 Siemens Aktiengesellschaft Dispositif d'emboutissage d'une pièce
DE102012102594B4 (de) * 2012-03-26 2014-05-08 Siempelkamp Maschinen- Und Anlagenbau Gmbh & Co. Kg Verfahren zum Herstellen von Formteilen aus Kunststoff
DE102014006729A1 (de) * 2014-05-08 2015-11-12 Kolbus Gmbh & Co. Kg Pressstempel mit Bremseinrichtung
CN109910354B (zh) * 2017-12-13 2021-03-26 宝沃汽车（中国）有限公司 压力机
CN108838260A (zh) * 2018-07-18 2018-11-20 重庆双龙机械配件有限公司 摩托车踏板冲压装置
WO2020097699A1 (fr) * 2018-11-14 2020-05-22 Drausuisse Brasil Comercio E Locacao De Unidades Hidraulicas Inteligentes S.A. Unité hydraulique avec pompes parallèles au cylindre pneumatique relié à un servomoteur et son utilisation
CN110695188A (zh) * 2019-09-23 2020-01-17 山东铭润电站装备有限公司 一种多用途龙门压力机和拼装式冲孔模具组成的冲孔设备
CN112605182A (zh) * 2020-12-30 2021-04-06 马鞍山博通数控模具有限公司 一种折弯机的钣金模具柔性使用方法
CN114019841A (zh) * 2021-09-27 2022-02-08 深圳市信成医疗科技有限公司 一种电动推杆控制电路

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WO2009026893A1 (fr) 2009-03-05

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