• 专利附录
  • 专利说明
  • 权利要求
  • 类似技术
  • 同族专利
  • 引用文献
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  • 优先权
    • 专利摘要:
    Shown here is a hydraulic control device for a press, in particular for a deep-drawing machine, with a working cylinder with which a workpiece, in particular by means of a workpiece holder or a deep-drawing pad, can be supported against the force of an upper tool. A regulation of the force applied to the workpiece during a pressing process takes place by means of throttling of a pressure medium volume flow to a working chamber in the working cylinder. Pre-energy recovery is a hydromachine arranged in a parallel print media circuit, through which controllable proportion of the print media volume flow flows. Furthermore, a press, in particular a deep-drawing machine, is shown with such a hydraulic control device. Page 24 of 24
    公开号:SE1351162A1
    申请号:SE1351162
    申请日:2013-10-02
    公开日:2014-04-09
    发明作者:Rolf Heidenfelder
    申请人:Bosch Gmbh Robert；
    IPC主号:
    专利说明:

    The disadvantage of this concept is that the pressure medium flowing through the choke device to the pressure medium sink constitutes a significant hydraulic energy loss. In this way, the hydraulic energy in the choke device is converted into heat which is difficult to utilize. On the contrary: it proves necessary to cool the choke device and the pressure medium flowing through it, so additional energy must be made available.
    In summary, a low energy efficiency is obtained with this press and this control device, respectively.
    In order to achieve energy-optimal conditions for the press and the control device, there are solutions in the prior art which have a second supply medium of low-pressure medium, in addition to the usual high-pressure medium supply. In this case, pressure medium under high pressure is used, in particular for the pre-acceleration of the piston from its rest position in the direction of movement of the upper tool. For the other phases in the pressing process, the pressure medium under low pressure is used instead. This reduces the energy consumption of the press or hydraulic control device compared to the previously described case.
    However, it is still a disadvantage that the amount of pressure medium that is forced out of the working chamber is relieved to tank pressure only by the choke device, which is disadvantageous from an energy point of view.
    In comparison with this, the invention is based on the task of creating a hydraulic control device for a press and a press with such a control device with improved energy efficiency.
    This object is solved with a hydraulic control device with the features according to claim 1 as well as a press with such a control device with the features according to claim 15.
    Advantageous developments of the invention are described in the dependent claims.
    A hydraulic control device for a press, in particular for a press designed as a punching machine or forming machine or deep-drawing machine, has a working cylinder with Page 2 of 24 10 15 20 25 30 at least one working chamber which is limited by a piston which can directly or indirectly support one in the press machinable workpiece against a tool in the press. In this case, a particularly continuously adjustable choke device is arranged in the first pressure medium circuit of the control device, preferably a control valve, with which the working chamber can be connected to a pressure medium sink. Through the choke device and the control valve, respectively, a pressure in the working chamber is controllable, and thus in particular a force acting on the workpiece.
    According to the invention, a hydromachine for recycling press work and press energy is arranged in a second printing medium circuit in the control device, in particular parallel to the first, through which the working chamber can also be connected to the printing medium sink.
    If the upper tool of the press - in particular a stamp - acts on the workpiece, there is in particular during an abstinence phase in the machining process - in particular in the case of deep drawing - the requirement that the piston withstands a force with a predetermined time course.
    The force is then apparent from the ratio "pressure in the working chamber" X "piston area". Control size is preferably the pressure in the working chamber. The regulation takes place in the usual way with the aid of the choke device, which can meet very high requirements for dynamics in the regulation of the pressure and thus the force, since very short set-up times are possible with it. With the help of this dynamic, process safety and the quality of the workpiece are positively affected. The pressure in the working chamber is then regulated in relation to the time and / or position of the upper tool by sufficiently strong or weak throttling of the outlet flow from or the inlet flow to the working chamber. The control function is preferably obtained by a control unit which for this purpose preferably contains a special workpiece or process-specific setpoint course for the pressure as a function of the time or the position of the upper tool. If the pressure medium were to flow only through the choke device, as already stated, a significant amount of hydraulic energy would be lost and converted into heat. An additional disadvantage would be that this heat must be removed, which would require a cooling unit of sufficient size with sufficient cooling effect.
    Here, the hydromachine which according to the invention is arranged in the second printing medium circuit: through its use the advantage of a high control dynamics is obtained by means of the choke device with simultaneous energy recovery by means of the hydromachine.
    Since the pressure medium during the pressing, in particular during the pre-acceleration phase and the restraining phase, is pushed out of the working chamber also into the second pressure medium circuit of the invention, the hydromachine arranged therein is driven in motor operation, whereby its output shaft provides a torque and a speed, ie a mechanical effect, available.
    From the output shaft, press energy and press work can thus be taken out, and the cooling effect required for the choke device is reduced to a corresponding degree, whereby the efficiency of the control device and the press, respectively, is increased. Preferably, a predominant proportion, for example 60 to 95%, particularly preferably 80 to 90%, of the pressure medium which is forced out of the working chamber is conducted via the second pressure medium circuit and the hydromachine, respectively. The corresponding remaining share, ie. for example 5 to 40%, particularly preferably 10 to 20%, are conducted via the first pressure medium circuit and its choke device.
    The setting of the ratio between the volume flow in the two printing medium circuits preferably takes place via a control unit and its control of the hydromachine. For this purpose, the stroke volume of the hydromachine is particularly preferably controlled in relation to the time and / or the position of the upper tool, which presupposes that the hydromachine is preferably designed with an adjustable stroke volume. Alternatively, it is of course also possible for the hydromachine to be designed with a constant stroke volume. The actual regulation of the pressure takes place simultaneously with this control by means of the throttling of the remaining part which is led away via the first printing medium circuit. Since this remaining proportion is less than the total pressure medium volume flow from the working chamber, the choke device is adjustable to a smaller opening diameter than would be the case in a conventional control device without a hydromachine.
    With the described interaction of the choke device and the hydromachine, the energy recovery is ensured at the same time with unreduced high control dynamics and precise pressure-related power control. Since in this way smaller amounts of pressure medium must be cooled down by the cooling unit and a lower cooling effect is thus required, a cooling pump can also be dimensioned smaller. Consequently, since the size of a tank is mainly determined by the size of the cooling pump, a smaller tank can also be chosen. Both factors individually or together mean that the cooling unit can be smaller, which reduces the space requirement for the control device or a press with this control device. It turns out that the cooling pump can be about 50% smaller and thus also the tank about 50% smaller.
    Furthermore, an overload protection is more easily performed with the aid of the second printing medium circuit.
    Page 4 of 24 10 15 20 25 30 In addition to this, the control device according to the invention enables, compared with known technology, an unreduced large piston speed, piston force, stroke number and dynamics as well as an unreduced large piston stroke. In addition, the control accuracy in terms of piston position and piston power is improved.
    The working cylinder preferably has an operating load of about 75 t to about 190 t. However, the control device can also be used to advantage for working cylinders with larger or smaller operating loads.
    The pressure media sink can have different pressure levels, especially for several tanks, or only one. In the latter case, it is advantageous if the print media sink consists of only one tank.
    The workpiece can preferably be supported by a workpiece holder or a deep drawing pad. The hydraulic control device is preferably used in a deep-drawing press.
    In a preferred further development, the hydromachine can be connected via a drive shaft, in particular an output drive shaft, to a power converter, in particular. In this case, the power converter is preferably an electrical machine which is designed in such a way that it can at least be operated in generator operation.
    Preferably, the electric machine is connectable or connected to a mains, to which it can supply current. Particularly preferably, the electric machine is also designed so that it can also be operated in motor operation, so that it can drive the hydraulic machine or another unit in the control device or on the press, for example a radiator or a hydraulic pump. Alternatively, the power converter is in particular another hydraulic machine which can be connected or in particular connected via the drive shaft and which can at least be operated in pump operation. For the same reason, this hydromachine is also particularly preferably designed so that it can also be driven in motor rift.
    In a particularly advantageous further development, the control device comprises a valve with which the second pressure medium circuit can be blocked. As a result, a pressure medium volume flow via the hydromachine to the pressure medium sinker can on the one hand be switched off, on the other hand also opened with high dynamics. The valve is preferably arranged in the second pressure medium circuit between the working chamber and the first hydromachine or between the hydromachine and the pressure medium container. Particularly preferably, the valve is designed as a 2/2-way valve with a spring-loaded shut-off position for shut-off and an actuatable flow-through position for controlling the second pressure medium circuit.
    A further advantage is obtained if the control device comprises a circulation flow circuit, with which a pressure medium connection to the at least one working chamber connected to the hydromachine can be connected to a pressure medium connection connectable to the pressure medium sink on the hydromachine. With such a circulation flow circuit, the control device is technically prepared for a circulation flow operation, as no energy recovery should or can take place. In circulation flow operation, the hydromachine preferably operates in pump operation and circulates pressure medium through the circulation flow circuit with predetermined stroke volume. If you are now going to switch from circulation flow operation to energy recovery with the help of the hydromachine, the hydromachine does not need to be accelerated from a speed = 0 and also already has the predetermined stroke volume, which is an important advantage compared to hydromachines driven at variable speeds. With circulation flow operation and circulation flow circuit, respectively, the inertia effects of the hydromachine can thus be minimized or eliminated, which has a positive effect on the dynamics of the pressure control. Particularly preferably, the circulation flow circuit is arranged together with the valve for shutting off the second pressure medium circuit.
    In a particularly advantageous further development, the circulation flow circuit comprises a non-return valve which opens towards the pressure medium connection on the hydromachine which can be connected to the at least one working chamber. In this case, the non-return valve is preferably arranged together with the valve for shut-off of the second pressure medium circuit.
    A particularly compact control device in terms of apparatus technology is obtained if the working cylinder is designed as double-acting and an additional working chamber which works in the opposite direction to the at least one working chamber is limited by the piston. The working cylinder is then preferably designed as a differential cylinder, the further working chamber preferably being passed through by a piston rod which can directly or indirectly support the workpiece.
    With this further working chamber, with the aid of the working cylinder, in addition to the functions of the at least one working chamber - the holding and a piston movement upwards in the direction of the upper tool - a lowering movement of the piston is also possible. The lowering movement is then first of all a safety function, as it takes place in the direction of a separation of the functional connection between piston and upper tool. Secondly, the lowering movement can be used to increase the pre-acceleration of the piston and thus the workpiece, whereby the quality of the workpiece, the number of strokes and thus also the production can be increased.
    A particularly advantageous further development of the control device comprises at least one hydraulic accumulator which can be connected to the working chamber, i.e. to the at least one working chamber and / or the additional working chamber acting in the opposite direction.
    As a result, the supply of pressure medium to the corresponding working chamber can take place very dynamically with the aid of the hydraulic accumulator.
    Preferably, at least one safety valve, in particular a Si logic valve, is arranged in a pressure medium circuit which connects the hydraulic accumulator to the at least one working chamber, in order to prevent an unintentional pressurization of the working chamber with pressure medium from the hydraulic accumulator and thus an inadvertent carbon target. Particularly preferably, two of the safety valves are arranged in series in this pressure medium circuit, which further increases the safety.
    A particularly advantageous further development includes an additional hydraulic accumulator which can also be connected to the working chamber, i.e. to said at least one working chamber and / or the additional working chamber which acts in the opposite direction, and which has a lower pressure than said at least one hydraulic accumulator. With the lower pressure hydraulic accumulator, the working chamber and / or the additional working chamber can be pressurized with lower pressure pressure medium in phases when no high piston forces and / or piston speeds are required, which is even more favorable from an energy point of view.
    A particularly advantageous further development comprises a hydraulic pump which can be coupled or in particular connected to the hydromachine for supplying pressure medium of the hydraulic control device and / or the press. The connection then preferably takes place to the output shaft of the hydraulic machine and the input shaft of the hydraulic pump. The two axes can also be easily made in one piece from a technical point of view. Through the coupling, the extractable energy from the hydromachine can in an technically simple manner be used immediately for supplying pressure medium to the hydraulic control device or the press. In this case, it is possible to dispense with an electric motor intended solely for the hydraulic pump and use the previously described electric machine 7 for operating the hydraulic pump. Particularly preferably, a pressure medium outlet from the hydraulic pump can be connected to one and / or the additional hydraulic accumulator, so that the pump can charge the hydraulic accumulator and the accumulators, respectively. Alternatively or in addition, the pressure medium outlet from the hydraulic pump can be connected to the working chamber and / or the additional working chamber, so that the piston can be moved with a volume flow from the hydraulic pump. This is particularly advantageous when the hydraulic accumulator or accumulators are not charged or cannot be charged.
    The choke device is preferably designed as a directional valve with a locking position which closes the first pressure medium circuit, and at least with control positions for outlet flow which can connect the at least one working chamber with the pressure medium sink via the first pressure medium circuit. The directional valve is then preferably designed as at least one 2/2 directional valve.
    In a particularly advantageous further development, the directional valve is designed in such a way that the hydraulic pump's pressure medium connection to the working chamber or chambers and / or to the hydraulic accumulator or accumulators also takes place by means of it. It is then preferably a 3/2-way valve and comprises control positions for the inlet for the pressure medium connection.
    The directional valve is preferably electromagnetically actuated to its control positions. Its locking position is preferably spring-loaded.
    For reading the process quantities required for the previously described regulation and / or control, the control device in an advantageous further development comprises a pressure sensor and a position sensor with which the pressure in the working chamber and the stroke of the upper tool in the press or of the piston can be read. These sensor units can then preferably be brought into signal connection with a control unit in the control device.
    With the control unit, preferably a pressure medium volume flow from the hydromachine and the remaining part of the at least one working chamber displaced by the piston via the second pressure medium circuit can be controlled in relation to the time and / or the stroke.
    Page 8 of 24 10 15 20 25 30 Preferably, the stroke volume is at least in the hydromachine adjustable and controllable by means of the control unit. Furthermore, the stroke volume in the hydraulic pump is preferably adjustable and controllable by means of the control unit.
    The speed of the hydromachine is preferably constant. Preferably, the speeds of the hydromachine, power converter and hydraulic pump are equal.
    A press, in particular a deep-drawing machine or a punching machine or a forming machine, has a hydraulic control device according to the invention and according to at least one of the aspects in the above description. Furthermore, it has an upper tool which acts in the opposite direction to the piston, in particular a piston, whereby the workpiece can be applied a force through the interaction of the piston with the piston. With the hydromachine according to the invention and the pressure control through the choke device, the same distributor for the press is obtained as those already described above.
    In a particularly advantageous further development of the press, it is designed as a deep-drawing machine with a tool holder and a deep-drawing pad, respectively, which can be supported by the piston.
    Particularly preferably, the press comprises the hydraulic pump as previously described, wherein the hydraulic pump is connected directly to the hydromachine or via the power converter.
    In the following, with reference to five figures, two design examples of a press according to the invention are explained.
    Figure 1 shows a wiring diagram for a first design example of a press according to the invention with hydraulic control device according to the invention.
    Figure 2 shows a wiring diagram for a second design example of a press according to the invention with a hydraulic control device according to the invention.
    Figure 3 shows a detailed diagram of the first design example according to Figure 1.
    Figure 4 shows schematic processes for a piston stroke, a pressure medium volume flow in the working chamber, an opening diameter in the choke device and a pressure in the working chamber and a force of the piston, respectively, in relation to time, and Page 9 of 24 10 15 20 25 30 Figure 5 shows a simulated process for the volume of print media fl the fate of the working chamber, in relation to time.
    For the following captions, components and devices that remain the same in all design examples have been provided with the same reference numerals.
    A press 1 according to figure 1 has an upper tool 4, driven by an eccentric drive 2. The tool is connected to the drive 2 with a link rod 6. The press 1 is designed as a deep-drawing machine.
    For applying a force to a workpiece, the press 1 comprises a tool holder 10 and a deep-drawing pad, respectively. During a pressing process, a working force is applied to the workpiece 4 by the upper tool 4 by means of abutment from the deep-drawing pad 10.
    In order to be able to regulate the force, a holding force of tool holder 10 relative to the upper tool 4 is adjustable with a hydraulic control device 12. This has a working cylinder 14 with a piston 16, which defines a working or pressure medium chamber 18 which acts in the opposite direction to the upper tool 4. Piston 16 supports the tool holder 10 and thus also the workpiece placed between the tool holder and the upper tool 4. The working cylinder 14 is designed as a double-acting differential cylinder and comprises, in addition to working chamber 18, a further working chamber 20. On its side there is a piston rod 22 through the further working chamber 20 and stored on tool holder 10.
    For the supply of printing medium and for diverting printing medium, the working lines 24, 26 are connected to the working chambers 18, 20. Working line 24 is then divided into a first printing medium circuit 28 and into a second printing medium circuit 30. Via the two printing medium circuits 28, 30, working chamber 18 can be connected to a printing medium sink. respectively a tank T. In the first pressure medium circuit 28 a choke device 32 arranged as a 3/2-way valve is arranged and in the second pressure medium circuit 30 a hydraulic machine 34, designed as an adjustable axial piston machine in oblique disc design. Throttle device 32 has a stop position (a) and drain flow control positions (b). It is continuously adjustable and electromagnetically adjustable. Furthermore, it comprises the control modes for inlet (c) and has three connections: a pressure connection P, a tank connection T and a consumer connection A. The consumer connection A is connected to working chamber 18 via the consumer branch of the first pressure medium circuit 28 and the working line 24. The pressure connection P is via a high-pressure line 36 connected to a pressure medium outlet on a hydraulic pump 38, which is designed as an adjustable axial piston machine in oblique disc design. Tank connection T is connected to the tank T via the near-tank branch of the first pressure medium circuit. A tank branch of the second pressure medium circuit 30 is connected at one end to the tank and at the other end to a pressure medium connection on the hydromachine 34. The working branch near the chamber of the second pressure medium circuit 30 is connected to the second pressure medium connection on the hydraulic machine 34. A pressure medium inlet on the hydraulic pump 38 is connected to the tank.
    From the high-pressure line 36 a high-pressure line 40 is branched off, which is branched in partly a working line 26 and partly an accumulator line 42. To the accumulator line 42 are two gas-charged high-pressure accumulators HD connected. With a drive shaft 44, the hydraulic machine 34 is connected to an electric machine 46, which in turn is connected to the hydraulic pump 38 by a shaft 48. The electric machine 46 is connected to an electrical network via power lines.
    The following is an explanation of a press cycle by means of Figure 4 and Figure 1. Figure 4 shows four important properties of the press cycle in a simplified schematic form. Figure 4 at the top shows a movement ssl for a stamp belonging to the upper tool 4 according to figure 1 in relation to the time t as a dashed curve. Furthermore, a movement szk of the deep-drawing pad 10 according to Figure 1 is shown as a solid curve. Along the time axis, the diagram divides four different phases, I, ll, lll, IV and the recurring phase I. The phases are separated by vertical dashed lines that extend over all diagrams in Figure 4 for improved clarity. Below the guide time diagram at the top of Figure 4, a diagram with print media volume flow and time is shown. It shows the time course of the pressure medium volume flow Q as well as its direction in the working line 24 connected to the working chamber 18 according to Figure 1. Below this diagram, Figure 4 shows a course of the opening diameter of the choke device 32 according to Figure 1 in relation to time and said phases. The bottom diagram in Figure 4 shows the time course of a cylinder force and a pressure, respectively, in working chamber 18 according to Figure 1 in relation to the time and the phases. The following description of the press cycle is mainly based on Figure 4 and refers to components and reference numerals according to Figure 1.
    At a time = 0, the upper tool 4, respectively its stamp, and the deep-drawing pad 10 are separated from each other. This is shown in Figure 4 in that the curve sst runs above the curve szk. At this time, the choke device 32 is in its locked position (a), so that no pressure medium can flow in either direction through the working line 24.
    Consequently, the pressure medium volume flow Q = 0. The corresponding is shown in diagram A (t), which shows that the opening diameter A in the choke device 32 is equal to 0. In the lower diagram according to Figure 4 it is shown that a pressure in working chamber 18 at this time is constant. The pressure Page 11 of 24 10 15 20 25 30 prevails there is exclusively the result of the weight of the deep-drawing pad 10 and the piston 14 and, to a lesser extent, of the pressure medium in the further working chamber 20 and of the workpiece arranged on the deep-drawing pad 10. The force F formed by the pressure and the piston area of piston 16 then corresponds to the weight force of the said parts.
    At time t "a deepening of the deep drawing pad 10 takes place for a pre-acceleration of the workpiece with the aim of reducing a relative impact velocity of the piston of the upper tool 4 against the workpiece. Therefore the curve szk in figure 4 shows a negative slope. This phase is also called pre-acceleration phase. with ll. Approximately in the middle of the time span between the times t .. and t ". a downward movement of the piston of the upper tool 4 is also initiated, which is evident from the negative slope of the curve ssi. In order for the deep-drawing pad 10 to be able to perform the downward movement, the pressure medium must be able to flow out of the working chamber 18 via the working line 24. For this, the first pressure medium circuit 28 via the choke device 32 and according to the invention also the second pressure medium circuit 30 via the hydromachine 34 are available. In the second diagram from above according to Figure 4, the solid curve shows the entire print media volume flow exchanged with working chamber 18 via work line 24. The dashed, substantially linear curve shows the proportion of the total print media volume flow flowing through the second print media circuit 30. It is clear that a The proportion of the print media volume flow through the second print media circuit 30, independent of the phase of the test process at most times, is between about 70 and 80%. During phases l1 and lll, the pressure medium volume flow from working chamber 18 flows in the direction of the pressure medium depression T and is thus negative. During phase IV, when there is an upward movement of the piston 16 and thus the deep-drawing pad 14, the working chamber 18 is supplied with a positive pressure medium volume flow via the two pressure medium circuits 28 and 30 according to diagram Q (t) in Figure 4. Therefore, the solid and dashed curves run above the zero line in diagram Q (t).
    Looking at the third diagram in Figure 4, the A (t) diagram, it is clear how the opening diameter of the choke device 32 relates over time in phases I to IV. During the pre-acceleration phase II, the opening diameter A must first increase with the increasing demand for speed of the deep-drawing pad 10. At the same time, the stroke volume in the hydromachine 34 is controlled so that it increases approximately in proportion to the increase in the opening diameter.
    Page 12 of 24 10 15 20 25 30 At the time t. ", The piston of the upper tool 4 hits the deep-drawing pad 10, as can be seen from the coincident curves sst and sz., According to the diagram at the top of figure 4. From this time a force F and thus a pressure must Therefore, the working chamber 18 of the first pressure medium circuit 28 is connected via the control position of the choke device 32 to the outlet flow (b) to the pressure chamber of the first pressure circuit of the first pressure chamber 28 of the working chamber 18 in the working chamber 18, in this exemplary embodiment. As already in the pre-acceleration phase II, also during the resistance phase III pressure medium is diverted through both pressure medium circuits 28, 30 from the working chamber 18 via the working line 24. Thereby further pressure medium energy is recovered in the hydromachine 34 while the pressure in the working chamber is regulated by the drain position control mode (b) in the choke device 32.
    This regulation is clear from diagram A (t) with the slightly wavy curve in resistance phase III. Apart from a slight increase in the pressure in the working chamber 18 and of the abutment force F, respectively, which is shown as a peak in the diagram at the bottom of Figure 4 at the beginning of the abrasion phase, Figure 4 clearly shows that the pressure control produces a substantially constant pressure in the working chamber 18 and thus a essentially constant resistance.
    The restraint phase lll ends at a time t | v and transitions to an upward movement.
    At that time, the upper tool 4 according to Figure 1 moves upwards due to the eccentric drive. At the same time, the working cylinder 14 is controlled in such a way that pressure medium is returned to working chamber 18 via work line 24. Even during this phase, it is clear from the second diagram in Figure 4 that the proportion of the supplied pressure medium flow through the hydromachine 34 is approximately 70 to 80%. The remaining proportion comes via the choke device 32 and via its control positions for inlet (c), respectively. Consequently, the aperture diameter A in the control positions (c) of the inlet during the upward phase IV will first increase and towards the end of this phase at time t | again reduce to zero. At this time, the piston 16, the deep-drawing pad 10 and the plunger of the upper tool 4 are again in their initial positions as at time t = 0.
    The diagram in Figure 4 shows in a striking way that there is a great potential for energy recovery, in particular in phases I, III and IV.
    This potential is utilized by hydromachine 34, on the output shaft 44 of which figure 1 a speed and a torque can be taken out during phases 11 and III. If the electric machine 46 is then operated in Page 13 of 24 10 15 20 25 30 generator operation, it can supply electrical power to a network. This power can be used directly, for example to drive the hydraulic pump 38 or other units. In an alternative design example different from Figure 1, one can also eliminate the interconnected electromachine 46 and connect the hydraulic pump 38 directly to the hydromachine 34. In this way, the hydromachine 34 in phases 11 and / or III, when pressure medium flows from the working chamber 18, supports the operation of hydraulic pump 38 and thereby contributes to the recovery of energy. With the hydraulic pump 38, the two hydraulic accumulators according to Figure 1 can then be charged with hydraulic energy via the high-pressure line 36 and the accumulator line 42.
    Figure 2 shows a second design example of a press 101, which substantially corresponds to the press 1 according to Figure 1. Unlike press 1, a hydraulic control device 112 for press 101 comprises, in addition to the hydraulic pump 38, a hydraulic pump 138 coupled via a shaft 148. With hydraulic pump 138 thereby a low pressure circuit in the hydraulic control device and a low pressure accumulator ND are supplied with pressure medium.
    The low pressure accumulator ND is connected to a pressure medium outlet on the hydraulic pump 138 via an accumulator line 142. Analogously, a high pressure accumulator HD is connected to a pressure medium outlet on the hydraulic pump 38 via the high pressure line 36 and the accumulator line 42. For connecting the additional working chamber 20 to either the high pressure or the hydraulic control device 112 comprises a 3/2-way valve 150. It has a working connection B which is connected to the further working chamber 20 in working cylinder 14 via a working line 152 to the pressure connection P on the choke device 32 and a working line 154 branched therefrom. connected to a high pressure connection PH on the 3/2 directional valve 150. The low pressure line emanating from the hydraulic pump 138 is instead connected to a low pressure connection PN on the direction valve 150. The directional valve 150 is electromagnetically actuatable and has a locking intermediate position (a), in which In a high pressure position (c), on the other hand, the high pressure accumulator HD is connected to the working connection B via accumulator line 42 and the high pressure connection PH, so that the further working chamber 20 is pressurized with pressure medium. pressure via work line 154. This occurs in particular during the pre-acceleration phase ll. For all other mentioned phases, on the other hand, the directional valve 150 is actuated to its low-pressure position (b), where the low-pressure connection PN and thus the low-pressure accumulator ND and the hydraulic pump 138 are connected to the working connection B. In this state the lower pressure in the additional working chamber 20.
    In order that the working chamber 18 can also be pressurized with the different pressures, the choke device 32 must be actuated to its control positions for inlet (c), so that the pressure connection P is connected to the working line A.
    Figure 3 shows a very detailed representation of the first design example according to Figure 1. It serves as a description of the components required for the said control and regulation of the press 1; 101 and the hydraulic control device 12, respectively; 112. This description also applies to the second design example according to Figure 2. The components already described in Figure 1 are not treated here, they have the same reference numerals as in Figure 1.
    For the control of the hydromachine 34 and the control of the choke device 32, the hydraulic control device 12 according to Figure 3 has several sensors for reading the necessary process quantities as well as a control unit and the necessary signal connections and lines, respectively. It comprises a position and angle sensor unit 60 which can read the angle of rotation of the drive 2. The position sensor unit 60 is connected to the control unit 62 via a signal line 61. Furthermore, the control device has a pressure sensor unit 64 with which a pressure in the further working chamber 20 can be read and which is connected. to the control unit 62 with a signal line 65. Furthermore, it has a pressure sensor unit 66 with which a pressure in the working chamber 18 can be read and which is also connected to the control unit 62 via a signal line 67. Furthermore, it has a position sensor unit 68 with a distance and a position of the piston 16 can be read and which is connected to the control unit 62 with a signal line 69. The signal lines 61, 65, 67, 69 have for the sake of clarity been shown with interruptions.
    Control unit 62 thus obtains by means of the said sensor units and signal lines at each time of the pressing process information about the positions of the upper tool 4, the piston 16 and the deep drawing pad 10 and the workpiece, as well as information about the pressure prevailing in the working chambers 18, 20. mentioned, the control quantity is then the temporal course of the pressure in working chamber 18. This should course is stored in the control device 62.
    Page 15 of 24 10 15 20 25 30 To control the stroke volume of the hydromachine 34, the control unit 62 is connected to a control device 72 for the hydromachine 34 via a signal line 70. The control device 72 then acts via a signal line 73 on an electromagnet in a 3/2-way valve in a hydraulic actuator 74 for the hydromachine 34. The actuator 74 is connectable to a control pressure source 75 via the directional valve.
    The detailed representation of Figure 3 in the first design example according to Figure 1 further shows a valve 76, which is designed as a 2/2-way valve and which can block the second pressure medium circuit 30 against the tank T and the pressure medium sink, respectively. Valve 76 therefore has a capillary-loaded locking position and a flow-through position which can be actuated electromagnetically via signal line 79 from the control unit 62. Valve 76 is arranged between hydromachine 34 and the tank.
    To enable a circulation volume flow at the shut-off valve 76, a circulation flow circuit 80 is branched off from the branch of the second pressure medium circuit 30 on the tank side, i.e. at a location between the hydromachine 34 and the valve 76. The circulation flow circuit opens into the branch of the second pressure medium circuit 30 which is connectable to the working chamber 18. In the circulating flow circuit 80 a non-return valve 82 is arranged which opens towards the pressure medium connection of the hydromachine 34 connectable to the working chamber 18. Via the said circulation flow circuit 80, the non-return valve 82 and the valve 76, it is now possible to provide a circulation or bypass volume flow past the hydromachine 34 in those phases of the pressing process where no pressure medium volume flow should and / or can flow via the second pressure medium circuit 30 and the hydromachine 34. the hydraulic machine 34 goes into pump operation, driven by the electric machine 46, and has a stroke volume controlled by control unit 62 and a controlled speed. This operating condition is preferably maintained as long as there is no need to absorb a pressure medium volume flow flowing out of the working chamber.
    This is particularly possible and advantageous during the pre-acceleration phase II according to Figure 4, during which a pre-acceleration of the deep-drawing pad 10 for adaptation to the speed of the upper tool 4 takes place. During this pre-acceleration phase, the control unit 62 holds the valve 76 in the locked position shown in Figure 3. As soon as the upper tool 4 comes into contact with the workpiece, at time tm the pressure control in the control unit 62 for the pressure in the working chamber 18 begins. time be particularly advantageous, since the hydromachine 34 then already has the Page 16 of 24 10 15 20 25 30 Stroke volume required and does not need any time for an angle for increasing the stroke volume starting from 0. At the time t ". the control unit 62 is only ensured that the valve 76 is switched from the shut-off position to the flow-through position and the electric machine 46 is switched from motor operation to generator operation.
    The hydraulic control device 12 has a pressure relief valve 84, with which a pump pressure and thus a pressure in the pressure medium line 40 and the hydraulic accumulator HD can be limited.
    Furthermore, the hydraulic control device 12 has two series-connected safety valve devices 86, through which a pressurization of the working chamber 18, which is operative in the direction of a frictional connection of the deep-drawing pad 10 to the upper tool 4, is secured.
    Figure 5 shows the result of a simulation of the pressure medium volume flow Q via the first pressure medium circuit 28 and the choke device 32 for two conventional control devices according to the prior art and for the control device according to the invention according to the first design example. The dashed curve in the diagram shows a conventional control device, which operates only with one level for the pressure medium supply and without the second pressure medium circuit according to the invention. The dash-dotted line in Figure 5 shows a conventional hydraulic control device, which operates with two different pressure levels, analogous to the previous description of the second design example, but without the second pressure medium circuit according to the invention. The third, solid curve represents the pressure medium volume flow via the choke device 32 in the first design example according to Figures 1 and 3. However, it also applies qualitatively to the second design example according to Figure 2.
    Starting during rest phase I, the pressure medium volume flow via the choke device 32 - i.e. the remaining part which does not flow via the hydromachine of the pressure medium volume flow displaced from the working chamber - according to Figure 5 is equal to 0. With the pre-acceleration phase II the pressure medium volume flow decreases rapidly to all negative curves. . At time tm the resistance phase lll begins.
    Here the great advantage of the hydraulic control device according to the invention is now shown. It is clear that the pressure medium volume flow flowing via the choke device 32 in the hydraulic control device according to the invention (solid line) is considerably less than the flow in the usual control devices (dash-line and dashed line). In the choke device, therefore, relatively less energy is converted into heat than with known technology. The power that can be taken out of the output shaft 44 is approximately proportional to the difference between the pressure medium volume flows, which is represented by the double arrow in Figure 5.
    Shown here is a hydraulic control device for a press, in particular for a deep-drawing machine, with a working cylinder with which a workpiece, in particular by means of a workpiece holder or a deep-drawing pad, can be supported against the force of an upper tool. A control of the force applied to the workpiece during a pressing process takes place by means of a throttling of a pressure medium volume flow to a working chamber in the working cylinder. For energy recovery, a hydromachine is arranged in a parallel print media circuit, through which a controllable proportion of the print media volume flow flows. Furthermore, a press, in particular a deep-drawing machine, is shown with such a hydraulic control device.
    Page 18 of 24 10 15 20 25 30 List of reference numerals 1; 101 2 4 6 10 12; 112 14 16 18, 20 24, 26 28 30 32 34 36 38; 138 40 42; 142 44 46 48; 148 150 152, 154 60 61 62 64 65 66 67 68 69 70 Press Excenterd rift of tool Link Rod Toolholder Hydraulic control device Working cylinder piston work chamber Arbetsledning first fluid pressure circuit by fluid pressure circuit Drosselanordning Hydro Machine High-pressure line Hydraulic High-pressure line Ackumulatorledning shaft Electromagnetic machine axis Directional valve Supervision Area Sensor unit Signal line Controller Pressure Sensor unit Signal line Pressure Sensor unit Signal line Position sensor unit Signal line Page 19 of 24 10 72 73 74 75 76 79 80 82 84 86 Control unit Signal line Actuator Control pressure source Valve Signal line Circulation flow circuit Check valve Pressure relief valve Safety valve device Page 20 of 24
    权利要求:
    Claims (16)
    [1]
    Claims 1
    [2]
    Hydraulic control device for a press (1; 101) with a working cylinder (14) with at least one working chamber (18), which is limited by a piston (16), in which a workpiece directly or indirectly machinable in the press (1; 101) can be supported against an upper tool (4), wherein in the first pressure medium circuit (28), through which the working chamber (18) is connectable to a pressure medium sink (T), an adjustable choke device (32) is arranged with which a pressure in the working chamber (18) is adjustable, characterized in that a second printing medium circuit (30), through which the working chamber (18) is connectable to the printing medium sink (T), is provided with a hydromachine (34) for recycling press work.
    [3]
    Control device according to claim 1, wherein the hydromachine (34) can be connected to a power converter (46) via a drive shaft (44).
    [4]
    Control device according to claim 2, wherein the power converter is an electrical machine (46) which is designed in such a way that it can at least be operated in a generator operation.
    [5]
    Hydraulic control device according to at least one of the preceding claims with a valve (76), with which the second pressure medium circuit (30) can be blocked.
    [6]
    Control device according to at least one of the preceding claims, with a circulating flow circuit (80), with which a pressure medium connection connectable to said at least one working chamber (18) on the hydromachine can be connected to a pressure medium connection connectable to the hydromachine (34).
    [7]
    A control device according to claim 5, wherein a non-return valve (82) is arranged in the circulation flow circuit (80) which opens towards the pressure medium connection which can be connected to said at least one working chamber (18).
    [8]
    Control device according to at least one of the preceding claims, wherein the working cylinder (14) is designed as double-acting and the piston (16) delimits a further working chamber (20) which works in the opposite direction to said at least one
    [9]
    9. Page 21 of 24 10 15 20 25
    [10]
    10.
    [11]
    11.
    [12]
    12.
    [13]
    13.
    [14]
    14.
    [15]
    15. Chamber of Deputies (18). Control device according to at least one of the preceding claims with a hydraulic accumulator (HD, ND), which can be connected to the working chamber (18). Control device according to at least one of the preceding claims with a hydraulic pump (38; 38, 138) connectable to the hydromachine (34) for supplying pressure medium to the hydraulic control device (12; 1 12) and / or the press (1; 101). Control device according to at least one of the preceding claims, wherein the throttle device is designed as a directional valve (32) with a locking position (a), which can close the first pressure medium circuit (28), and with control positions (b) for outlet flow which can connect the at least one working chamber (18) to the print media sink (T) via the first print media circuit (28). Control device according to claim 10, wherein the directional valve (32) comprises control positions for the inlet (c), with which said at least one working chamber (18) can be connected to a source of pressure medium. Control device according to at least one of the preceding claims, with at least one pressure sensor unit (66) and with position sensor units (60, 68) which can read the pressure in said at least one working chamber (18) and the stroke of an upper tool (4) in the press (1; 101) and with the piston (16) and with a control unit (62) which is in signal connection with the sensor units. Control device according to claim 12, wherein a pressure medium volume flow through the hydromachine (34) is controllable in relation to the time or stroke of the control unit (62). Control device according to claim 12 or 13, wherein a stroke volume at least of the hydromachine (34) is adjustable and controllable with the control unit (62). Press with a hydraulic control device (12; 112) according to at least one of the preceding claims and with an upper tool (4) acting in the opposite direction to the piston (16), Page 22 of 24
    [16]
    16. whereby a workpiece can be applied a regulated force by the interaction of the upper tool (4) with the piston (16). Press according to claim 15 with the hydraulic control device (12; 112) according to claim 9 or a claim referring thereto, wherein the hydraulic pump (38; 38, 138) is connectable to the hydraulic machine (34) or connected to it. Page 23 of 24
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