Classifications

• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B30—PRESSES
  • B30B—PRESSES IN GENERAL
  • B30B1/00—Presses, using a press ram, characterised by the features of the drive therefor, pressure being transmitted directly, or through simple thrust or tension members only, to the press ram or platen
  • B30B1/26—Presses, using a press ram, characterised by the features of the drive therefor, pressure being transmitted directly, or through simple thrust or tension members only, to the press ram or platen by cams, eccentrics, or cranks
  • B30B1/266—Drive systems for the cam, eccentric or crank axis
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B21—MECHANICAL METAL-WORKING WITHOUT ESSENTIALLY REMOVING MATERIAL; PUNCHING METAL
  • B21D—WORKING OR PROCESSING OF SHEET METAL OR METAL TUBES, RODS OR PROFILES WITHOUT ESSENTIALLY REMOVING MATERIAL; PUNCHING METAL
  • B21D24/00—Special deep-drawing arrangements in, or in connection with, presses
  • B21D24/04—Blank holders; Mounting means therefor
  • B21D24/08—Pneumatically or hydraulically loaded blank holders
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B21—MECHANICAL METAL-WORKING WITHOUT ESSENTIALLY REMOVING MATERIAL; PUNCHING METAL
  • B21D—WORKING OR PROCESSING OF SHEET METAL OR METAL TUBES, RODS OR PROFILES WITHOUT ESSENTIALLY REMOVING MATERIAL; PUNCHING METAL
  • B21D24/00—Special deep-drawing arrangements in, or in connection with, presses
  • B21D24/10—Devices controlling or operating blank holders independently, or in conjunction with dies
  • B21D24/14—Devices controlling or operating blank holders independently, or in conjunction with dies pneumatically or hydraulically
• • 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

Definitions

• the invention is based on a press with a hydraulic drive as indicated in the preamble of claim 1.
• Press ram For presses, a distinction is made depending on the type of drive Press ram between hydraulic and mechanical presses.
• the press ram of a hydraulic press is operated by a hydraulic cylinder driven. This type of drive is first of all common for very large presses with high press force.
• a metal forming press with a press ram and a counter holder and with a hydraulic drive is e.g. known from DE-AS 20 43 967 (closest prior art). At this Press is pressed into the oil by a pump during the advance of the counter holder pumped the hydraulic cylinder. When the counter holder reaches its end position has reached, the pressure medium supply from the pump driven by an electric motor to the cylinder is interrupted. A certain pressure must be maintained in the cylinder if the counterhold during the return stroke of the Press ram is displaced. It is common knowledge that Pressure medium for this via a pressure relief valve, a throttle valve or drain a proportional valve into the pressure medium tank allow. In print this is e.g. in the EP 0 173 755 B1. When the pressure medium drains through the pressure relief valve or the throttle valve becomes much there Generates heat that is lost unused. Possibly. is even one Cooling and thus additional construction work necessary.
• a hydrostatic press used for sheet metal forming and which has a press ram and a counterholder is also known from FR-A 24 49 490.
• the disclosed hydraulic press is a pressure chamber of the hydraulic cylinder with which the counter-holder can be moved via a line connected to a pressure-controlled hydraulic motor, over the during the return stroke of the counter holder from the pressure chamber displaced oil flows and with it in the pressure chamber Pressure is maintained.
• the hydraulic motor drives together another motor, which is probably an electric motor acts, a hydraulic pump, from the pressure medium into a pressure chamber of a hydraulic cylinder assigned to the press ram is. In this way, a hydraulic press good efficiency achieved.
• Regarding the funds for the Drive of the counter holder in the forward stroke is based on known hydraulic Press drives referenced.
• Presses of small and medium size are mostly mechanical Presses in which the press ram is mechanically driven by a crank mechanism is driven by an electric motor.
• Such a Electromechanical drive of the press ram is favorable in terms of efficiency and usually quite inexpensive.
• the invention has for its object a press, which the features from the preamble of the claim 1 has to train so that despite the increased Use of hydraulic components a favorable energy balance is obtained, i.e. the losses of unusable energy are low.
• the drive should also be inexpensive.
• the hydrostatic machine is for the counterhold according to claim 2 also with a quantity-dependent Provide control to which the pressure control is superior. This means that during the forward stroke the cylinder with constant, but by changing the swivel angle of the hydrostatic machine adjustable speed is moved.
• third hydrostatic machine provided that is hydraulic with the second hydrostatic machine is coupled.
• the second hydrostatic machine in the drive rod of the press ram maintains their speed particularly precisely when they is regulated according to claim 11, wherein the drive train of the press ram then also contain a hydraulic accumulator can.
• a particularly advantageous embodiment of an inventive Press contains claim 6. After that is a first connection of the second hydrostatic machine with a pressure medium reservoir connected. Also are a second connection of this machine, the hydraulic cylinder of the counter holder and the pressure side of the first, pressure-controllable and of a motor-driven hydrostatic machine with each other connected.
• the hydraulic drive is expedient designed so that the first pressure-controllable hydrostatic Machine that can be pivoted on both sides can, no pressure medium displaced to the pressure medium reservoir becomes. If pressure was displaced over them, it would also the first hydrostatic machine to work as a motor and power to the electric via the electric motor connected to it Return network.
• the first, pressure-controllable machine is to be connected to the second connection of the second hydrostatic machine a quasi-stationary pressure maintain.
• Move slowly around the counter holder To be able to is according to claim 7 between the second terminal the second machine and the pressure side of the first machine on the one hand and the hydraulic cylinder, on the other hand, preferably adjustable flow valve arranged in one direction of the hydraulic cylinder effective and in the other direction is ineffective.
• This ineffectiveness in the other direction is achieved according to claim 8 very simply that in the bypass to the flow valve to the hydraulic cylinder non-return valve is arranged.
• the counterstroke's return stroke prevails in the hydraulic cylinder and in the lines between it and the pressure side of the first machine and the second port on the second machine is the one set on the first machine Pressure.
• a valve is provided with which the pressure medium flow is lockable to the hydraulic cylinder of the counter holder.
• the counter-holder in the setup or Trial operation can be lowered without the press ram emotional. It is conceivable that for such a lowering Pressure medium from the hydraulic cylinder via the first hydrostatic Lower the machine and swivel this machine on both sides and to equip it with a flow control. Indeed then first discharges itself possibly with the pressure side of the Machine connected hydraulic accumulator up to the load pressure of the counter holder, before it moves. The may be moving Counterholder starting from a position below its upper one First stop upwards. The counterhold finally reaches its lower stop, the hydraulic accumulator empties continue. When switching on the drive, it is therefore necessary to first recharge the hydraulic accumulator to the set pressure.
• a press ram is in a frame 10 11 guided vertically. It is mechanically driven by a crank mechanism driven one in one direction rotating crank 12 and a coupling rod 13, which on her one end articulated to the crank 12 and at the other end is articulated to the plunger 11.
• the plunger 11 bears on its side facing the press table 14 One die side 15.
• On the press table 14 is the associated tool patrix 16 attached.
• the tool patrix 16 is surrounded by an annular counter-holder 17 which over individual bolts 18 passed through the press table 14 a support plate 19 located below the press table 14 is supported.
• the support plate 19 is from the plunger 20 of a plunger cylinder 21 carried on the frame 10 sits and is arranged centrally to the plunger 11 so that the Plunger 20 and with it the support plate 19, the bolts 18 and the counter holder 17 perform movements in the vertical direction can.
• first hydrostatic machine 30 which is pivoted on both sides, axial piston machine with pressure control is formed mechanically with a fixed coupling 31 Three-phase motor 32 coupled. Hydrostatic swiveling on both sides Machines are well known. It is only again mentioned that this feature entails that under Maintaining the direction of rotation of the volume flow within one such machine and the direction of action of the torque reversed can be.
• the axial piston machine 30 is on one side via a Line 33 with the cylinder 21 and on the other side with a Oil reservoir 34 connected. It has a quantity-dependent Control, but the pressure control is superior.
• the axial piston machine 30 is used to lift the plunger 20 operated as a pump.
• the speed at which the Plunger 20 moves thereby, is due to the quantity Control specified.
• the axial piston machine 30 only promotes the Leakage oil losses.
• the support plate 19 is in position shown in which she said the stop of the frame is present. It can be seen that the counter-holder 17 with the press ram 11 facing top of the male tool 16 is aligned and under a sheet placed on the die 16 35 protrudes.
• the press ram 11 moves due to the advance of the forward stroke its weight down and eventually jams due to of the pressure prevailing in the cylinder 21 the sheet between the Tool die 15 and the counter holder 17. With the further Movement of the press ram 11 downwards during the working cycle of the forward stroke, the counter-holder 17 against that in the cylinder 21 prevailing pressure, the sheet between the die 15 and counterholder 17 remains pinched and over the male tool 16 is pulled.
• the pressure medium is out the cylinder 21 via the axial piston machine 30 into the oil collection container 34 ousted.
• the axial piston machine works here as an engine.
• the three-phase motor drives together with the axial piston machine 30 32 in the embodiment according to FIG. 1, a hydraulic pump 40 (third hydrostatic machine) operating in a closed hydraulic circuit hydraulic with a hydraulic motor 41 (second hydrostatic machine) is connected. Without this is shown in more detail, the leakage at the hydraulic pump 40 and on the hydraulic motor 41 in a manner known per se by a Auxiliary pump replaced from a small container permanently sufficient liquid volume via a check valve Low pressure side of the closed circuit promotes.
• the hydraulic motor 41 drives the crank 12 via the fixed clutch 27.
• the speed of the hydraulic motor 41 is said to be largely constant, however be adjustable.
• the hydraulic motor is therefore equipped with a tachometer generator 42 provided, which taps the speed of the hydraulic motor 41. Depending on the tapped speed, the hydraulic pump 40 regulated so that the liquid flow delivered to a largely constant speed of the hydraulic motor 41 leads.
• the hydraulic machine 30 is also used in the embodiment according to FIG driven by a three-phase motor 32 via a clutch 31.
• the hydraulic pump 40 is through a hydrostatic machine 50 (third hydrostatic machine) and the hydraulic motor 41 through a hydrostatic machine 51 (second hydrostatic machine) replaced.
• Both hydrostatic machines 50 and 51 are preferred Axial piston machines. These machines are on line 52 connected to each other and each connected to the oil reservoir 34.
• a hydraulic accumulator 53 hangs on line 52 With the help of the pressure-controlled axial piston machine 50 and the hydraulic accumulator 53 becomes a largely constant in line 52 Maintain pressure regardless of that of the axial piston machine 51 torque required at constant speed.
• the axial piston machines 50 and 51 and the accumulator 53 containing circuit is a so-called secondary regulated circuit in which the speed of the secondary unit 51 scanned with the help of the tachometer generator 42 and kept at a largely constant but adjustable value becomes.
• the swing angle of the secondary unit 51 is about tracked a control process of the size of the torque present.
• the axial piston machine 30 used in motor operation to drive the pump 40, so that the conversion mechanical-hydraulic energy into electrical energy is avoidable.
• the embodiment according to Figure 2 corresponds insofar as that of Figure 1, but there is the speed the axial piston machine 51 because of the secondary regulated circuit adhered to better than the speed of the axial piston motor 41 of the embodiment according to FIG. 1. This appears because of the influence the axial piston machine 30 to the axial piston pump 50 particularly favorable in the drive train of the press ram 11. Furthermore can with extreme load distribution from the counterholder over the Axial piston machine 30 excess energy in the hydraulic accumulator get saved. Otherwise, both the axial piston machine 30 and the axial piston machine 50 over the Three-phase motor 32 deliver power to the mains.
• a hydrostatic machine is also used in the embodiment according to FIG 30, which is pivoting on both sides, with a bare Pressure control provided axial piston machine is formed via a fixed coupling 31 mechanically with a three-phase motor 32 coupled.
• Pressure control here means that the swivel angle the machine is set so that the machine such a volume of pressure medium is pumped that a certain pressure occurs on the pressure side. In the present In this case this pressure should correspond to the pressure in the Hydraulic cylinder 21 must prevail so that the sheet 35 firmly between the counter-holder 17 and the die 15 is clamped.
• the hydrostatic machine 30 in terms of its regulation of the local one hydrostatic machine 50 corresponds.
• This hydrostatic machine 30 serves the hydrostatic machine driven by the motor 32 3 for lifting the counter-holder 17. It is therefore provided with the reference number 30 and as the first hydrostatic machine consider.
• This hydrostatic machine 30 according to FIG 3 is on its pressure side via a line 33 to the cylinder 21 and on the other hand with the oil collection container 34 connected.
• line 33 are in series with one another adjustable flow valve 120 and an unlockable check valve 121 arranged, which blocks to the hydraulic cylinder 21 out. in the A check valve 122 is bypassed to the flow valve 120, which also locks to the hydraulic cylinder 21.
• the hydrostatic machine 51 as in the execution after Figure 2 is coupled to a tachometer generator with which the Speed of the machine 51 is tapped with a first Connection with the pressure medium reservoir 34 and with a second connection via a line 52 immediately, ie under Bypassing the valves 120, 121 and 122, with the pressure side of the Machine 30 connected. There is also a hydraulic accumulator on line 52 53 attached.
• the hydrostatic machines 30 and 51 as well the memory 53 belong to a secondary regulated circuit, in which the speed of the machine 51 is regulated. By change the machine automatically searches for the swivel angle the required torque to the existing one Operating pressure in line 52 the predetermined speed to be able to hold. Is e.g. the machine a little too slow, like this the swivel angle is increased and thus the torque somewhat increased until the target speed is reached.
• the hydraulic machine 30 is shown as pivoting on both sides. However, the drive should be designed so that no drain of pressure medium to the tank via the machine 30 takes place. During this drain, machine 30 would operate as a motor and drive the motor 32 so that energy into the electrical Grid would be fed. Because the conversion of mechanical is lossy in electrical energy, this should be avoided by designing the drive accordingly will. The machine 30 can then be pivoted on one side Be trained machine.
• the valve is in the state of the press shown in FIG 121 unlocked and in the hydraulic cylinder 21 and in line 52 there is the pressure set on the machine 30, that of the counter pressure corresponds.
• the plunger 11 moves down and finally takes the counterholder 17 and thus the piston 20th With.
• Pressure medium is displaced from the cylinder 21, the over check valve 122 and line 52 to machine 51 and flows through this to the tank 34. Only additional, from the machine 51 required pressure medium volume is from the machine 30 promoted.
• the valve 121 can now be closed briefly, to lift the plunger 11 alone.
• the valve 121 is unlocked again, so that pressure medium from the pressure side of the machine 30 into the hydraulic cylinder 21 flows, the prevailing in line 52, the counter pressure corresponding, regulated pressure via the flow valve 120 on the for lifting the counter support 17 inclusive the pin 18, the support plate 19 and the piston 20 necessary Load pressure is reduced.
• valve 121 For sole setup or trial operation of the press ram when the counterholder is lowered, the valve 121 remains blocked.

Landscapes

• Engineering & Computer Science (AREA)
• Mechanical Engineering (AREA)
• Press Drives And Press Lines (AREA)
• Control Of Presses (AREA)
• Fluid-Pressure Circuits (AREA)
• Shaping Metal By Deep-Drawing, Or The Like (AREA)

Applications Claiming Priority (5)

Publications (2)

Family

ID=25913291

Family Applications (1)

Country Status (7)

Cited By (1)

Families Citing this family (29)

Family Cites Families (13)

• 1993
  • 1993-03-25 CZ CZ932262A patent/CZ281492B6/cs not_active IP Right Cessation
  • 1993-03-25 JP JP5516968A patent/JPH06510949A/ja active Pending
  • 1993-03-25 US US08/142,490 patent/US5499525A/en not_active Expired - Fee Related
  • 1993-03-25 WO PCT/DE1993/000275 patent/WO1993019866A1/de active IP Right Grant
  • 1993-03-25 DE DE4309641A patent/DE4309641A1/de not_active Withdrawn
  • 1993-03-25 EP EP93907756A patent/EP0586669B1/de not_active Expired - Lifetime
  • 1993-03-25 ES ES93907756T patent/ES2114044T3/es not_active Expired - Lifetime
  • 1993-03-25 DE DE59308158T patent/DE59308158D1/de not_active Expired - Fee Related

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