Planetary gear transmission systems or components – Input from independent power sources – Including electric motor input
Reexamination Certificate
1999-03-22
2001-02-27
Marmor, Charles A (Department: 3681)
Planetary gear transmission systems or components
Input from independent power sources
Including electric motor input
C100S048000
Reexamination Certificate
active
06193625
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a method of controlling a ram speed of a press ram of a metal-forming press, comprising the steps of superimposing a second drive energy from an auxiliary drive on a first drive energy from a main drive and driving the press ram at the resultant speed. The present ivnention additionally relates to a driving device for a press ram of a metal-forming press.
2. Description of the Invention
The prior art discloses a large number of solutions for determining a drive characteristic (speed profile) of the press ram of a metal-forming press during a total cycle (one stroke) of the press ram, said total cycle consisting of energy supply, acceleration of the press ram, stationary phase, energy recovery and metal-forming phase.
It is, for example, known to equip a press drive with two flywheels and the associated clutches and to adjust a desired speed profile of the press ram by alternately actuating said clutches. Such drives are, however, comparatively complicated and uneconomical as far as the energy consumed is concerned.
It is also known to use for press drives of metal-forming presses single-stage planetary gearings in the case of which two different output speeds of the gearing are provided via clutch/brake combinations.
For decelerating the press ram (negative acceleration) the energy that has to be removed from the drive when shifting to a lower speed is normally dissipated as lost energy towards the machine frame and converted into frictional energy (heat) which is not suitable for further use.
German Patent No. DE 40 24 290 discloses the measure of superimposing an auxiliary drive on a main drive so as to realize arbitrary speed profiles for the press ram. The moments of inertia which have to be overcome for introducing the auxiliary energy are, however, substantial.
SUMMARY OF THE INVENTION
Hence, it is the object of the present invention to provide a method of controlling a ram speed of a press ram of a metal-forming press of the kind cited at the start and a driving device for a press ram of a metal-forming press, in particular for carrying out said method, which permit the speed profile of the press ram to be adjusted with high variability during a stroke of said press ram, and which additionally permit an adjustment of the speed characteristic of the press ram which has been improved significantly as far as the energy balance is concerned.
In the case of a method of the kind mentioned at the beginning, this object is achieved in that for a positive acceleration of the press ram the second drive energy is taken from an energy storage device and that for a negative acceleration of the press ram energy is fed back into said energy storage device.
Preferably, the moments at which the positive and the negative acceleration of the press ram begin and end are selectable freely with respect to a crank angle of a drive of the press ram so that the speed of the press ram during its phases of movement is variable with the aid of the auxiliary drive in the range of arbitrary positive and negative angles of rotation of a crankshaft driving the press ram, including the possibility of a standstill of the press ram and of a reversal of its operating movement. With the aid of the method according to the present invention, the energy which is inevitably released during a deceleration phase of the stroke in connection with the necessary speed reduction is not dissipated as energy loss but stored in energy storage devices as energy which can be reused for the future process and fed back into the press drive.
On the one hand, the control for the main movement of stroke-bound metal-forming machines can be rendered more flexible by means of said method, and, on the other hand, said method can also be used for achieving in an advantageous manner the desired impact speed of the press ram at the beginning of the metal-forming process in combination with an optimized use of energy. At the same time, it is also possible to adapt the speed characteristic of the press drive to the most advantageous speed profile of the associated handling means used for operating a metal-forming press.
With regard to the driving device for a press ram of a metal-forming press comprising a main drive and an auxiliary drive for varying a speed characteristic of the press ram in dependence upon the crank angle of said main drive, the above-mentioned object is achieved in that the auxiliary drive is arranged between the main drive and an energy storage device.
Preferably, the main drive is implemented as a motor-controlled flywheel drive with a differential gear, which is preferably implemented as a planetary gearing, and the energy which can be returned to the auxiliary drive via a process control means can be taken especially from an energy supply system acting as an energy storage device or from a discrete energy storage device, such as a magnetic-dynamic storage device or a hydraulic accumulator.
BRIEF DESCRIPTION OF THE INVENTION
REFERENCES:
patent: 4586400 (1986-05-01), Nygen
patent: 4825721 (1989-05-01), Gabriele
patent: 5129317 (1992-07-01), Gloe et al.
patent: 5211610 (1993-05-01), Hurth
patent: 5425682 (1995-06-01), Hayashi
patent: 5460084 (1995-10-01), Otremba et al.
patent: 5588344 (1996-12-01), Chun
patent: 5799744 (1998-09-01), Yamaguchi et al.
patent: 629792 (1936-04-01), None
patent: 4004290 (1990-09-01), None
patent: 295 589 A5 (1991-11-01), None
patent: 44 21 527 A1 (1995-12-01), None
patent: 116014 (1984-08-01), None
patent: 561604 (1993-09-01), None
patent: 2258186 (1993-02-01), None
patent: 59-70497 (1984-04-01), None
Peter F. Brosch; “Moderne Stromirichterantriebe: Arbeitsweise drehzanhlveränderlicher Antriebe met Stromrichtern”; 1992; pp. 32-34; Chapter 6.2.4.
Morgenstern Karlheinz
Ullrich Jens
Fraunhofer-Gesellschaft zur Förderung der angewandten Forschung
Laubscher & Laubscher
Marmor Charles A
Pang Roger
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