EP3280554B1 - Forging hammer and method for controlling the working cycle of a forging hammer - Google Patents

Description

The underlying invention relates to a forming machine, in particular a forging hammer, and to a method for controlling a corresponding forming machine.

Various drive concepts are known for driving forming machines such as forging hammers. For example, it is from the generic prior art DE 20 2014 104 509 U1 known that forging hammers can be operated with electric linear motors.

Furthermore describes the DE 20 2014 104 509 U1 , a forging hammer for the reshaping of workpieces, comprising a striking tool and a hydraulic linear drive coupled to the striking tool and designed to drive the striking tool with a hydraulic circuit comprising a pressure accumulator, a hydraulic cylinder, in particular a differential cylinder, connected downstream of the pressure accumulator via a directional valve assembly, and comprising the Furthermore, a control unit designed at least for controlling the directional valve assembly.

The EP 0 116 024 B1 describes in connection with hydraulic machines the use of a pressure accumulator and hydraulic motor for the operation of hydraulic cylinders. The EP 0 116 024 B1 also describes that elastic energy stored in the hydraulic system during operation of hydraulic machines can be converted into electrical energy by a hydraulic generator connected in parallel with the hydraulic pump in terms of fluid technology, the hydraulic generator being connected to the hydraulic circuit in order to generate the electrical energy.

The known forming machines, in particular forging hammers, definitely leave room for improvements and variations with regard to drive, energy efficiency and achievable working speeds.

In this respect, an object of the present invention can be seen in particular in further developing and / or improving the known forming machines, in particular with regard to drive, energy efficiency and / or achievable working speeds.

According to the invention, this object is achieved in particular by configurations corresponding to the features according to patent claims 1 and 8. Further configurations, developments and variants result in particular from the dependent claims and from the following description of exemplary embodiments.

The forming machine according to the embodiment according to claim 1 comprises an impact tool, for example an upper, lower die and / or bear, which e.g. can be designed as such as a forming tool, or can have a forming tool, and / or can have an interface for receiving, in particular fastening, a forming tool.

The forming machine further comprises a hydraulic linear drive designed to drive the striking tool and coupled to the striking tool for the purpose of driving the striking tool. In the context of this application, a hydraulic linear drive is to be understood to mean drives which are in particular designed to convert hydraulic energy into kinetic energy of a linear movement. For example, the hydraulic linear drive can comprise a hydraulic cylinder driven by a hydraulic fluid and acting as a linear motor. In a solution proposed here, a differential cylinder is proposed as the hydraulic cylinder, which has, for example, a piston guided in a cylinder tube with a one-sided of which can have a extending piston rod on which the striking tool, in particular the bear, can be fixed. At this point it should be noted that the invention can also be applied to any hydraulic cylinder.

A first fluid space, which is formed on a side of the piston of the hydraulic cylinder facing away from the piston rod or is formed in operating states, is usually referred to as a piston space, and in particular in the sense of the underlying invention. Usually, and in the sense of the underlying invention, a second fluid space formed between the piston and the cylinder tube in an operating state of the hydraulic cylinder, in particular a differential cylinder, through which the piston rod extends or through which the piston rod can extend is referred to as an annular space.

The hydraulic linear drive comprises a hydraulic circuit with a servomotor hydraulic pump, i.e. a hydraulic pump coupled to its operation with a motor-driven servo motor. The servo motor hydraulic pump is set up in such a way that the pump speed or pump power can be controlled by the servo motor.

According to the invention, the servo-motoric hydraulic pump is configured as a unidirectional servo-motoric hydraulic pump using the directional valve assembly proposed here and is integrated in the hydraulic circuit. With regard to the hydraulic pump, the term unidirectional should in particular be understood to mean that, when the forming machine is in operation, hydraulic fluid always flows through the pump in the same direction of flow, or that the hydraulic pump uses the same in one or more successive working cycles of the hydraulic cylinder, in particular differential cylinder Pump direction or direction of rotation is operated. The unidirectional flow direction or pump direction can in particular be defined by a flow direction from one, in particular central, hydraulic tank to the hydraulic cylinder, in particular Differential cylinder, in particular to the piston space or to the annular space of the differential cylinder.

A hydraulic pump which is unidirectional in terms of fluid technology makes it possible, in particular, to achieve advantageous control times for the volume flows provided to the hydraulic system or the volume flows required by the hydraulic system.

The hydraulic pump can in particular be a constant pump, i.e. a hydraulic pump with a constant displacement.

The servomotor hydraulic pump proposed here enables the volume flow and / or pressure of the hydraulic fluid in the hydraulic circuit to be adapted comparatively precisely and quickly to the respective requirements and adjusted accordingly. The latter is of particular advantage for the comparatively high piston speeds and piston accelerations that occur with forging hammers. In particular, the pump speed or hydraulic power of the hydraulic pump can be optimally adapted to the movement phases that follow one another during a forging cycle and can be adjusted according to the respective requirements, while maintaining comparatively short control times.

The movement profile of the piston, for example the speed, in particular the final speed reached immediately before the bear or tool hits a workpiece, can be set or controlled comparatively precisely by controlling the hydraulic circuit in a correspondingly precise and timely manner. Ultimately, this has an advantageous effect on the achievable forging or forming result, and an energy-efficient operation can advantageously be achieved.

In the case of forging hammers in particular, the hydraulic pump of the hydraulic linear drive can be designed for comparatively high volume flows of, for example, 100 l / min to 500 l / min or more. In particular, in the case of even larger volume flows, a plurality can be connected in parallel in terms of fluid technology Hydraulic pumps are used. A pressure range in which the hydraulic pumps work, i.e. a hydraulic pump pressure, can be in the range between 190-220 bar.

As already mentioned, the hydraulic linear drive comprises a hydraulically operating or hydraulically operated hydraulic cylinder, in particular differential cylinder, in particular a double-acting hydraulic cylinder with a piston rod extending on one side of the piston. The hydraulic cylinder, in particular differential cylinder, or generally formulated the hydraulic linear motor, is fluid-technically with a directional valve assembly, i.e. a module comprising at least one, in particular directly controlled or piloted, directional valve, connected, and arranged downstream of the hydraulic pump via the directional valve assembly. This means that the hydraulic cylinder, in particular differential cylinder, can be supplied with hydraulic fluid during operation by the hydraulic pump.

Connected via the directional control valve assembly should in particular mean that the first fluid space, e.g. the piston chamber of the differential cylinder can be supplied or acted upon with hydraulic fluid in one switching position of a (directional) valve or a (directional) valve group, can be separated from the differential cylinder in another switching position, and / or in another switching position with a second one Fluid space, e.g. the annulus of the differential cylinder, can be fluidly connected. In particular, it should be noted that the directional valve assembly two, e.g. can have exactly two switching positions, the hydraulic pump being connected to the first fluid space, in particular piston space, in a first switching position, and to the second fluid space, in particular annular space of the differential cylinder, in a second switching position. Further or more detailed explanations for the connection also result from the explanations described below.

The hydraulic circuit further comprises a servo-motoric hydrogen generator, ie a hydraulic motor coupled to a servo motor that works as a generator. The hydrogenerator can, for example, be designed for volume flows in the range of 300 l / min. For higher volume flows, several hydrogen generators or hydraulic motors connected in parallel in terms of fluid technology can be used.

The servomotor-driven hydrogenerator is in particular designed and connected to the hydraulic circuit in such a way that when hydraulic fluid is acted on and the shaping machine is operating properly, it works as a generator, i.e. Generate electrical energy from hydraulic energy. The hydraulic motor can generate mechanical work from hydraulic energy for driving the regenerative servomotor, that is to say servo generator, wherein the servo generator can convert the mechanical energy into electrical energy.

According to the invention, the servo-motoric hydrogenerator is configured as a unidirectional servo-motoric hydrogenerator using the directional valve assembly proposed here and is integrated in the hydraulic circuit. With regard to the term unidirectional, reference is made to the above statements. In particular, with regard to the hydrogenerator, this is to be understood to mean that, when the forming machine is in operation, hydraulic fluid always flows in the same direction of flow through which the hydraulic motor or that the hydraulic motor in one or more successive working cycles of the hydraulic cylinder, in particular differential cylinder, with the same direction of rotation or The direction of flow of the hydraulic fluid is operated. The unidirectional flow direction or direction of rotation can in particular be defined by a flow direction from the hydraulic cylinder, in particular differential cylinder, in particular piston space or to the annular space, to a, for example central, hydraulic tank of the hydraulic system.

It is provided that the hydrogenerator is connected downstream of the hydraulic cylinder, in particular differential cylinder, in terms of fluid technology via the directional valve assembly. Overall, fluid-technical interconnections of the hydraulic pump, hydraulic cylinder, in particular differential cylinder, and hydrogen generator can thus be carried out can be achieved in which hydraulic pump, differential cylinder and hydrogen generator are connected in series essentially always or in one or more predetermined time periods during a working cycle of the hydraulic cylinder, in particular differential cylinder, which should mean that hydraulic fluid flowing into a fluid space of the hydraulic cylinder, in particular differential cylinder is always provided by the hydraulic pump, and hydraulic fluid flowing away from the hydraulic cylinder, in particular differential cylinder, is always discharged via the hydrogenerator.

By using and integrating the servo-motoric hydrogenerator, it is possible to extract hydraulic energy from the hydraulic fluid flowing from the hydraulic cylinder, in particular the differential cylinder, in accordance with the respective control of the regenerative servo motor of the hydrogenerator. In particular, the hydrogen generator can be operated as a hydraulic brake for the piston of the hydraulic cylinder, in particular a differential cylinder, by means of a corresponding torque control of the regenerative servomotor. In particular, it is possible to actively brake the piston and thus the striking tool.

With the arrangement and hydraulic interconnection of the hydraulic motor and hydrogen generator proposed here, it is possible to actively accelerate and actively brake the piston essentially at any time during the working cycle by means of appropriate control, without a reversal, i.e. Reversal of the direction of rotation at the hydraulic pump or hydrogenerator would be required. The latter in particular has an advantageous effect on energy efficiency and the achievable control accuracy and speed, and can ultimately also lead to improvements in the forming quality.

Apart from the fact that the hydrogenerator can be used as an active hydraulic brake for the piston, the hydrogenerator can also be used for energy recovery, in that superfluous elastic Energy is extracted from the hydraulic system by appropriate control of the hydrogenerator.

The forming machine further comprises at least one control unit designed and designed to control at least the hydraulic pump, the hydrogen generator and the directional control valve assembly, in particular at least in sections or overlapping at the same time.

In particular, by appropriately controlling the directional valve assembly by means of the control unit, the hydraulic pump, hydrogenerator and directional valve assembly can be connected in series over an entire working cycle of the differential cylinder or at least over a substantial part of the working cycle, so that a defined and comparatively accurate movement control of the hydraulic cylinder, in particular Differential cylinder, can be achieved by hydraulic coupling of the hydraulic cylinder, in particular differential cylinder, to the hydraulic pump. Simultaneously or parallel to this, in particular over the entire working cycle, elastic or hydraulic energy stored or generated in the hydraulic system or hydraulic circuit can be converted into electrical energy by corresponding control of the hydrogenerator.

It has been shown that the fluidic connection of the hydraulic pump, hydraulic cylinder, in particular differential cylinder, and hydrogen generator proposed here enables simultaneous operation of the hydraulic pump and hydrogen generator to be implemented, with advantageous effects on control precision and energy efficiency of the forming machine.

Especially with forging hammers with comparatively high speeds, e.g. from 2m / s to 5m / s, and comparatively high accelerations on the striking tool, the hydraulic pump and the hydrogenerator proposed here and the hydraulic interconnection of the hydraulic pump and the hydrogenerator proposed here over the entire working cycle an essentially continuous motion control is achieved what is of decisive advantage for precise forging results, while at the same time a comparatively energy-efficient operation is possible in comparison with conventional forging hammers.

In embodiments, the control unit can be set up in such a way that the directional valve assembly is controlled at least temporarily during a working movement or a working cycle of the hydraulic cylinder, in particular differential cylinder, or the switching position of the directional valve assembly is set such that the hydraulic pump with the first fluid chamber of the hydraulic cylinder, in particular the piston chamber, and the hydrogenerator are fluidically connected to a second fluid chamber of the hydraulic cylinder, in particular the annular chamber of the differential cylinder. With regard to the terms piston chamber and annulus, reference is made to the above explanations, which apply accordingly.

The control unit can also be set up so that at least temporarily during a return movement, i.e. a movement opposite to the working movement, of the hydraulic cylinder, in particular differential cylinder, the directional valve assembly is controlled such that the hydraulic pump is fluidically connected to the second fluid chamber of the hydraulic cylinder, in particular the annular chamber, and the hydrogen generator is connected to the first fluid chamber of the hydraulic cylinder, in particular the piston chamber of the differential cylinder.

In particular, the control unit can be set up in such a way that it controls the directional valve assembly in such a way that the hydraulic pump is connected or alternately connected to the first fluid space, in particular the piston space, and the second fluid space, in particular the annular space, in sequentially successive, in particular immediately successive, sections of a working cycle of the differential cylinder is. Accordingly, the hydrogenerator can alternately be connected alternately to a second fluid space, in particular an annular space, and a first fluid space, in particular a piston space.

In particular, with such a control and alternating connection of the hydraulic pump and the hydrogenerator, the hydraulic cylinder, in particular differential cylinder, and in particular the striking tool, with continuous motion control between the reversal points of the hydraulic cylinder, in particular differential cylinder, and in particular also in the area of the reversal points, combined with energy recovery the hydraulic generator are operated.

In embodiments, the directional valve assembly can comprise a 4/2 way valve.

In embodiments, the directional control valve assembly can in particular comprise four individual hydraulic valves that are fluidly connected to one another in a bridge circuit. A bridge circuit can be understood in particular as a ring circuit of, for example, four hydraulic valves with intermediate connection points. For example, such a bridge connection can be implemented by connecting two hydraulic valves connected in series.

In embodiments, the hydraulic circuit can comprise at least one suction valve, which is fluid-technically connected to a suction source, for example a hydraulic fluid reservoir or reservoir; or tank, on the one hand and with at least one fluid space, in particular the piston space and / or annular space, of the differential cylinder on the other hand.

The fluidic connection of the suction valve can in particular be designed in such a way that a negative pressure which arises in the at least one fluid space during operation of the hydraulic cylinder, in particular a differential cylinder, can be compensated for by sucking in hydraulic fluid via the suction valve. Corresponding negative pressures can occur in a forging hammer, for example in the annular space when the impact tool rebounds, and / or when in an operating state the volume increase in the piston space is greater than the volume provided by the hydraulic pump of hydraulic fluid. The latter can occur, for example, if the volume flow generated by the hydraulic pump remains or is smaller than or becomes the change in volume of the piston space caused by enlarging the piston space, which is the case, for example, after initially accelerating the piston towards the workpiece in order to regulate the required speed of the percussion tool Case may be.

The replenishment valve can be, for example, a hydraulic valve designed in the manner of a check valve, in particular a valve that automatically closes on one side. The suction valve can, for example, be designed for volume flows in the range between 150 l / min to 10,000 l / min. The respective design of the replenishment valve depends, among other things, on the respective stroke volume and the piston speeds that occur.

In embodiments, the control unit can be set up to control the pump speed of the hydraulic pump such that the hydraulic pump is always operated at least at a non-zero minimum speed during operation, in particular during one or more successive working cycles. This should mean in particular that the hydraulic pump is controlled in such a way that the pump speed is not below a non-zero limit. This can be achieved in particular by the hydraulic interconnection of the components of the hydraulic circuit proposed here in combination with the use of a servo-motor hydraulic pump proposed here.

In embodiments, the control unit can be designed and set up in such a way that it controls the hydraulic pump or can control such that during operation, in particular a working section of one or more working cycles, the hydraulic cylinder, in particular the differential cylinder, has at least one different from zero Minimum speed is operated.

In particular, the control unit can be set up in such a way that the hydraulic pump is always operated at least at the minimum speed during one or more immediately successive working cycles. This means in particular that in a corresponding mode of operation the minimum speed represents the lower limit for the speed of the hydraulic pump. The hydraulic pump is therefore not stopped completely during appropriate operation, but is operated continuously, which can bring advantages in terms of energy efficiency and accuracy of setting the speed, in particular the final speed, of the forging tool.

In embodiments, the control unit can be set up in such a way that the hydraulic pump is first activated or is activated at the minimum speed, and then the pump speed is initially increased from the minimum speed to a maximum speed in a working area of a working cycle of the hydraulic cylinder, in particular differential cylinder. In a subsequent working section, the pump speed can be reduced from the maximum speed to the minimum speed, in particular in such a way that the minimum speed is reached or is present at a reversal point of the hydraulic cylinder, in particular a differential cylinder. The reversal point is preferably the reversal point of the piston of the hydraulic cylinder, in particular the differential cylinder, facing the area of action of the striking tool.

According to refinements, the increase in the pump speed of the hydraulic pump or the reduction in the pump speed of the hydraulic pump can take place in accordance with a linear function of time. In particular, the control unit can be configured in such a way that the maximum speed is or is reached before reaching or at the time the impact tool strikes a workpiece positioned in the work area.

To achieve a predetermined final speed of the striking tool, it can be provided in embodiments that the pump speed of the hydraulic pump is reduced when the maximum speed is reached, so that under the action of the hydraulic forces prevailing in the hydraulic circuit and, if applicable, the force of gravity acting on the striking tool, the or a predetermined final speed has been reached in or shortly or immediately before the reversal point, or forming point, or in or short or immediately before the reversing point of the forming point. To set the top speed, the hydrogenerator can also be operated as a hydraulic brake in order to actively brake the piston.

In particular, it follows from the above explanations that by appropriately controlling the hydraulic pump and the hydrogenerator, the sequence of movements, in particular the final speed, of the hydraulic cylinder, in particular differential cylinder, and thus of the striking tool can be varied and adjusted comparatively flexibly within the limits given by the overall structure of the forming machine . In particular, a suitable control of the pump speed of the hydraulic pump, optionally with the additional use of suitable sensors for measuring the position and / or speed of the hydraulic cylinder, in particular differential cylinder, or the striking tool, and / or sensors for measuring one or more pressures prevailing in the hydraulic system comparatively accurate and reliable adjustment of the impact speed or final speed of the striking tool can be achieved.

In accordance with the aforementioned statements, the forming machine, for example interacting with the control unit, can have sensors which are designed to determine the position of the hydraulic cylinder, in particular differential cylinder, and / or the impact tool. Furthermore, sensors for measuring the pressure in the hydraulic circuit, for example in a line opening into the first fluid space, in particular piston space, and or in a line opening into the second fluid space, especially annular space, can be attached. The sensors can be coupled to the control unit, so that values for pressures and / or position of the striking tool or hydraulic cylinder, in particular differential cylinder, transmitted from the sensors to the control unit for controlling the hydraulic pump and / or of the hydrogenerator can be used. The pressures and / or positions are preferably processed by the control unit and used to control the hydraulic pump and / or the hydrogenerator in such a way that the striking tool has the required final speed in or shortly or immediately before the point of impact.

In embodiments, it can be provided that during a return movement, i.e. a hydraulic cylinder, in particular differential cylinder, a working movement opposite to the aforementioned working movement, that is to say during a movement section in which the hydraulic cylinder, in particular differential cylinder, or the striking tool moves away from the workpiece after the shaping has taken place, the hydraulic pump is operated at the minimum speed, i.e. that the pump speed of the hydraulic pump is set to the minimum speed in this movement section. In particular, the operation at the minimum speed can be used to accelerate the bear and, in the case of an upper pressure forming machine, to drive the bear upwards.

In further refinements, it can be provided that the control unit is connected to sensors for measuring the speed of the hydraulic cylinder, in particular differential cylinder, or percussion tool, that is to say that the peripheral machine can comprise corresponding speed sensors, and determined speed data from the control unit for control or regulation the hydraulic pump and / or the hydrogenerator can be used to regulate the final speed to a predetermined value.

In particular, using the sensors proposed here in combination with the servo-controlled components, ie the hydraulic pump and the hydrogenerator, it is possible, for example, to have the end speed of the impact tool at the point of impact corresponding to the value required in each case. For example, different final speeds can be set essentially without great effort in successive work cycles.

In embodiments it can be provided that a starting point for starting a forming or forging process, in particular a starting point from which the piston or bear is accelerated in the direction of the forming area, depending on the respectively desired, required or predetermined final speed, corresponding to the respectively desired one , required or predetermined energy, in particular forming energy, depending on the height of the workpiece to be formed measured in the direction of movement of the piston, and / or depending on the respective forming path, for example for upsetting or reshaping the workpiece parallel to the direction of movement of the piston.

The starting point from which the acceleration of the bear takes place can be, in particular, a reversal point facing away from the forming area, in the case of an upper pressure forming machine, for example, an upper dead center of the piston or bear.

A variable setting of the starting point or output stroke from which the piston or striking tool, bear or die is accelerated, as described in particular in advance and possible in configurations, enables in particular an optimal setting of the movement sequence of the piston or bear, etc. It is also possible to variably adjust the stroke, for example the top dead center of the piston, so that, for example, improved forming or forging cycles, or forming or forging frequencies can be achieved.

In particular, in embodiments it is possible for the control unit to be designed in such a way that the path or corresponding strokes covered by the striking tool during a forging cycle are / are minimal. For example, the control unit can be designed and set up in such a way that different strokes, for example a minimally necessary stroke to achieve a desired or predetermined final speed or forming energy that follows in the forming operation, differ by targeted starting Reversal points, for example top dead centers of the piston, can be realized.

In particular, by using variable strokes of the piston, it is possible to optimize forming times, and the movement sequence depending on the desired final speed, forming energy, depending on the height of the workpiece to be formed in the direction of movement of the piston, and / or depending on the respective forming path, e.g. for upsetting or forming the workpiece parallel to the direction of movement.

In embodiments, the control unit can be set up and configured to use a starting point, in particular top dead center, of a preceding forming cycle, e.g. a starting point of the piston or bear or die at the beginning of a preceding forming cycle, in particular immediately preceding forming cycle, to determine a further starting point, in particular top dead center, of a subsequent, preferably immediately following, forming cycle.

In particular, the control unit can be designed to use e.g. the piston, bear or die of a first forming process, second control data for movement control e.g. the piston, bear or die of a second forming process. The second forming process can follow the first forming process directly in time. Optimized forming times can advantageously be achieved through such control of the forming processes, in particular successive forming processes. The second control data can be determined from the first control data on the basis of the first control data and the boundary conditions specified for the subsequent temporal forming process.

In refinements, it can be provided, for example, that an impact energy, for example forming energy, of a stroke last used is used for this purpose the starting position of the piston is calculated on the basis of a subsequently required impact energy from the control unit or control, in particular is determined automatically. For example, the starting position can be set depending on the respective height of the workpiece to be formed.

In embodiments, it can be provided that the position, in particular the starting position, of the piston, or bear, or die, is determined at the beginning or at a defined point in time during a forming or forging cycle and / or is used as a calculation basis for determining a starting position of the piston , Bears or dies and / or operating parameters for controlling the movement of pistons, bears and / or dies during or for a subsequent subsequent forming or forging process.

In embodiments, the control unit can be set up and designed such that it controls or can control the hydraulic pump in such a way that a maximum feed speed of the hydraulic cylinder, in particular differential cylinder, or of the striking tool is in the range between 1.5 m / s to 6 m / s, in particular at about 1.5 m / s or 5 m / s, or between 4.8 m / s and 5.5 m / s, and that preferably a maximum return speed of the hydraulic cylinder, in particular differential cylinder, in the range between 1.5 m / s and 2 , 5m / s, preferably 2m / s, in particular between 1.8 m / s and 2.1m / s.

In embodiments, it can be provided that the volume flow during braking in one or the other direction of movement of the piston, ie during the forward or backward movement of the piston, in the case of an overpressure forming machine when the piston moves up and down, is approximately the same. However, the volume flow can vary depending on the piston diameter, rod diameter, piston speed and others, or can be set depending on these sizes. The recovery of energy can take place in particular under roughly the same conditions of the reciprocating movement be optimized by means of the hydrogenerator, and overall an energy-saving operation can be achieved.

In embodiments, the forming machine can further comprise an energy store, which is connected to the hydrogenerator for the purpose of feeding in electrical energy generated by the hydrogenerator. In this way, the electrical energy generated by the hydrogenerator, or the electrical energy generated by the hydraulic energy of the hydraulic circuit by the hydrogenerator, can be temporarily stored, and can be made available again as electrical energy in a subsequent work cycle or working section of the converter rail, for example for Operation of the hydraulic pump. Apart from this, it is also possible for the electrical energy generated by the hydrogenerator to be fed into a power network or power-heat network connected to the forming machine.

It has been shown that the specific combination of the hydraulic components proposed here, in particular hydraulic motor, hydrogen generator and directional valve assembly and their connection, enables particularly precise and exact control of the forming machine, in particular the hydraulic cylinder, in particular differential cylinder, or percussion tool of the forming machine or is, at the same time a comparatively energy-efficient operation of the forming machine is made possible by a hydraulic circuit as proposed here.

According to claim 8, a method for controlling a work cycle of a forming machine is provided. The forming machine is a forging hammer.

In the method proposed here, it is provided that a hydraulic cylinder, in particular differential cylinder, coupled to an impact tool, is fluidly coupled via a hydraulic valve and a directional valve assembly connected upstream of the hydraulic cylinder. Servomotor hydraulic pump of a hydraulic linear drive is driven by the supply of hydraulic fluid. In particular, the hydraulic cylinder can be driven by acting on a fluid space, in particular the piston space or annular space of the differential cylinder.

In particular, it can be provided that, in particular if the hydraulic pump with a fluid space of the hydraulic cylinder, e.g. Piston chamber or fluid chamber of the differential cylinder, fluidically connected, from another fluid chamber of the hydraulic cylinder, in particular differential cylinder, hydraulic fluid, e.g. the hydraulic fluid flowing from the second fluid space, in particular the annular space, or the first fluid space, in particular the piston space, is directed via the directional valve assembly to a servo motor-driven hydrogenerator that is fluid-connected downstream of the directional control valve assembly.

In particular, this should mean that the hydraulic pump is fluidly coupled to a fluid space, and, at least in one section of the working cycle, in particular at the same time, the hydrogen generator is coupled to the further fluid space.

In this way, at least in the sections in which both fluid spaces are coupled to the hydraulic pump or hydrogen generator, in particular connected in terms of fluid technology, dual control of the hydraulic circuit is possible, which should mean that the hydraulic circuit can be influenced or influenced, in particular, by simultaneous control of the hydraulic pump and hydrogen generator .

In particular from the possibility of dual control of the hydraulic circuit on the one hand via the hydraulic pump and on the other hand via the hydrogen generator, the hydraulic cylinder, in particular differential cylinder, can be controlled comparatively precisely and reliably, as a result of which, in particular, improved forging results can be obtained.

In particular, it can be achieved in this way that the hydraulic motor and hydrogen generator are available during the entire working cycle of the hydraulic cylinder, in particular differential cylinder, and can be operated separately or simultaneously, as a result of which a comparatively exact control of the hydraulic cylinder, in particular differential cylinder, is achieved with simultaneously energy-efficient operation can be. For further advantages and advantageous effects, reference is made to the above statements, which apply accordingly.

In embodiments, it can be provided that during a working movement, in particular a feed movement in the direction of the working area or forming area of the hydraulic cylinder, in particular differential cylinder, the directional valve assembly is controlled in such a way that the hydraulic pump with the first fluid chamber, in particular the piston chamber, and the hydrogen generator with the second fluid chamber , in particular the annular space of the differential cylinder, are fluidically connected.

In further refinements, it can be provided that at least temporarily during a return movement of the hydraulic cylinder, in particular differential cylinder, i.e. during a movement of the hydraulic cylinder or percussion tool away from the working area or operating point of the hydraulic cylinder, in particular differential cylinder or percussion tool, the directional valve assembly is or is controlled such that the hydraulic pump with the second fluid space, in particular annulus, and the hydrogenerator with the first annulus, in particular Piston chamber, the differential cylinder are fluidly connected. Because of advantages and advantageous effects and / or further details of the mode of operation proposed here, reference is made in particular to the above explanations, which are used accordingly.

In embodiments, it can be provided that the hydraulic pump is controlled by the control unit such that the hydraulic pump is in operation is operated above or at least with a non-zero minimum speed.

In particular, in embodiments, the pump speed in a working section of a working cycle of the hydraulic cylinder, in particular differential cylinder, can first be increased from the minimum speed to a maximum speed and then reduced from the maximum speed to the minimum speed, for example in such a way that in the working area of the impact tool, the reversal point of the hydraulic cylinder in particular differential cylinder or piston the minimum speed is reached or is present.

The pump speed can be controlled, for example, according to a predefined function of the time and / or the position of the hydraulic cylinder, in particular a differential cylinder, for example in accordance with a linear relationship with time. However, control using at least partially non-linear relationships is also possible with the hydraulic system proposed here.

In embodiments, the pump speed can be set or regulated to the minimum speed during a return section of the working cycle of the hydraulic cylinder, in particular differential cylinder.

In embodiments, it can be provided that, in order to accelerate the hydraulic cylinder, in particular differential cylinder, that is to say the piston of the hydraulic cylinder, in particular differential cylinder, in the direction of a first reversal point assigned to a forming or working area of the forming machine, ie the hydraulic cylinder or differential cylinder or impact tool, the pump speed of the Hydraulic pump from the minimum speed, in particular in a linear dependence on the time, to the maximum speed, in such a way that the maximum speed is or is reached before reaching a first reversal point of the hydraulic cylinder, in particular differential cylinder, assigned to the forming area.

It can further be provided in embodiments that the control takes place in such a way that the pump speed of the hydraulic pump, i.e. the speed of the hydraulic pump of the hydraulic pump is reduced in such a way after reaching the maximum speed, in particular in a linear relationship with the time, that the minimum speed is reached or is set when the first reversal point is reached or is reached. For advantages or advantageous effects of corresponding configurations, reference is made to the above statements.

In embodiments, it can be provided that, when the first reversal point assigned to the forming area of the forming machine is reached or when a predetermined speed of the bear or the piston is reached, the directional valve assembly is controlled such that a pressure output of the hydraulic pump with the second fluid chamber of the hydraulic cylinder, in particular Annulus of the hydraulic cylinder, in particular differential cylinder, is or is fluidly connected, and that a pressure input of the hydrogenerator is or is fluidly connected to the first fluid chamber of the hydraulic cylinder, in particular piston chamber of the differential cylinder.

In particular with such configurations, an elastic energy stored, generated and / or generated in the hydraulic system of the forming machine, in particular potential energy stored in the hydraulic fluid, can be converted into electrical energy or another secondary energy form via the hydrogenerator, for example by decompression of the hydraulic fluid or the hydraulic system , and are fed to the metal forming machine, for example, in subsequent working cycles. In this context, reference is also made to the explanations above, which apply accordingly.

In embodiments, it can be provided that a negative pressure generated in the second fluid space, in particular the annular space, by rebound of the hydraulic cylinder, in particular differential cylinder, or percussion tool in the first reversal point, is compensated for by at least one suction valve, which on the one hand is fluidly connected to the second fluid space and on the other hand a hydraulic tank. Furthermore, it can be provided that an overpressure generated by the rebound in the first fluid chamber, in particular piston chamber, or an elastic energy generated in the hydraulic circuit is converted by decompression via or by the hydrogenerator into a secondary form of energy, for example electrical energy, and preferably in one Cache is saved. For advantages and advantageous effects, reference is made in particular to the statements above and below, which apply accordingly.

In embodiments, it can be provided that the directional valve assembly is controlled in such a way that, when or when, or immediately before, a second reversal point of the hydraulic cylinder, in particular the differential cylinder, facing away from the forming area of the forming machine, is actuated such that a pressure output of the hydraulic pump with the first fluid chamber, in particular Piston space, is or is fluidly connected, and a pressure input of the hydrogenerator is or is fluidly connected to the second fluid space, in particular the annular space of the differential cylinder.

In particular, it can be provided in embodiments that pressure fluctuations in the hydraulic system that may occur during a reversal of the pressure output of the hydraulic pump and the pressure input of the hydrogenerator are compensated for by one or more suction valves switched accordingly in the hydraulic circuit. In other words, suction valves can be provided such that any pressure fluctuations in the hydraulic system can be compensated for, in particular to avoid pressure peaks.

It is advantageously provided in embodiments that the movement control of the piston, bear and / or die by the control unit in or in the region of the two reversal points of the piston, apart from the rebound occurring only in the deforming reversal point, is carried out approximately or essentially in the same way becomes. This means in particular that, apart from the time span in which a rebound acts on the hydraulic system, essentially the same motion control can be used at both reversal points, possibly adjusted for gravity.

In embodiments, it can be provided that several successive work cycles are / are controlled according to one of the designs described above, the hydraulic pump and the hydrogenerator being continuously in the same direction of rotation during the work cycles, i.e. be operated without reversing the direction of rotation, and / or wherein the hydraulic pump is operated at least at the non-zero minimum speed over the several working cycles, and / or wherein secondary energy, for example electrical energy, generated by the hydrogenerator in one working cycle and / or partial working cycle subsequent working cycle and / or partial working cycle of the forming machine, in particular the hydraulic pump, is supplied. In this way in particular, advantageous energy efficiency can be achieved.

It is particularly clear from the above and previous explanations that the forming machine proposed here and the method proposed here for controlling the forming machine achieve the object on which the invention is based.

FIG. 1

eine schematische Darstellung des Aufbaus eines gemäß einer Ausgestaltung der Erfindung ausgebildeten Schmiedehammers;

FIG. 2

den Schmiedehammer nach FIG. 1 in einem ersten Betriebszustand;

FIG. 3

den Schmiedehammer nach FIG. 1 in einem zweiten Betriebszustand;

FIG. 4

den Schmiedehammer nach FIG. 1 in einem dritten Betriebszustand; und

FIG. 5

ein Arbeitsdiagramm betreffend Betriebs- und Steuergrößen des Schmiedehammers.

Exemplary embodiments of the invention are described in more detail below with reference to the attached figures. Show it:

FIG. 1

is a schematic representation of the structure of a forging hammer designed according to an embodiment of the invention;

FIG. 2nd

after the forging hammer FIG. 1 in a first operating state;

FIG. 3rd

after the forging hammer FIG. 1 in a second operating state;

FIG. 4th

after the forging hammer FIG. 1 in a third operating state; and

FIG. 5

a working diagram regarding operating and control parameters of the forging hammer.

FIG. 1 shows a schematic representation of the structure of an upper pressure forging hammer 1 designed according to an embodiment of the invention.

Components of the forging hammer 1 are described below using the FIG. 1 described in more detail, the function and operation of the forging hammer 1 in particular in connection with FIG. 2 to 5 are explained in more detail.

The forging hammer 1 comprises a frame (not shown) on which a differential cylinder 2 is fixed. A lower die 3 is also fastened to the frame with a lower tool 4 detachably attached thereto.

A piston rod 7, which extends on one side from the piston 6, is attached to a piston 6, which is guided in a longitudinally displaceable manner in a cylinder tube 5 of the differential cylinder 2.

At one end of the piston rod 7 remote from the piston 6 there is a bear 8, i.e. Blacksmith bear, upper die attached, which can be moved back and forth along with the piston 6 in the longitudinal direction of the cylinder tube 5.

The degree of freedom of movement of the piston 6 or bear 8 is in FIG. 1 represented schematically by means of a double arrow. In the present case, the forging hammer 1 is designed as a vertical forging hammer, which is to mean that, in the correct operating state, the bear 8 or an upper tool 9 detachably fastened to it moves in the vertical direction from top to bottom and vice versa.

In the example of the FIG. 1 The forging hammer 1 is shown in a working state in which the upper tool 9 rests on the lower tool 4, corresponding to a first turning point U1 of the bear 8 or upper tool 9.

The forging hammer 1 has a hydraulic circuit comprising the differential cylinder 2, with one, or, as required, a plurality of servo-motoric hydraulic pumps 27, which comprises a hydraulic pump 11 controlled by a servo motor 10, the pressure side 12 of which with a 4/2 way valve 13 and the suction side 14 thereof are fluidly connected to a hydraulic tank 15.

The hydraulic circuit further comprises a hydrogen generator 16, the input side 17 of which is connected to the directional control valve 13, and the output side 18 of which is fluidly connected to the hydraulic tank 15.

The forming machine 1 further comprises a control unit 19, which is designed and is provided with corresponding control lines, so that the components of the forging hammer 1, in particular the directional control valve 13, hydraulic pump 27, and hydrogen generator 16, and, if appropriate, further components can be controlled.

The control unit 19 can be configured with various sensors for detecting operating parameters of the forging hammer 1. For example, the forging hammer 1 can have one or more pressure sensors 20 with which, for example, a pressure prevailing in a piston chamber 21 of the differential cylinder 2 and / or in an annular space 22 of the differential cylinder 2 during operation of the forging hammer 1 can be detected, which pressure can be detected, for example, by the control unit 19 can be used to control the forging hammer 1, in particular the differential cylinder 2 and / or the hydraulic pump 27 and / or the hydrogenerator 16.

The hydrogenerator 16 comprises one, or, if necessary, several, hydraulic motors 28 and a servo generator 29 coupled mechanically to the hydraulic motor 28, i.e. a servomotor operated as a generator.

The hydraulic pump 27 and the hydrogen generator 16 can be controlled using the servo motor 10 and the servo generator 29, and for this purpose are connected to the control unit 19 via corresponding control lines. In particular, the hydraulic pump 27 and the hydrogenerator can be controlled in terms of speed and / or torque, for example in such a way that one for setting and / or reaching a predetermined or desired final speed of the bear 9 is achieved by. In particular, the hydraulic pump 27 and the hydrogenerator 16 can be controlled such that the bear 9 or piston 6 follows a predetermined movement sequence, the hydraulic pump 27 and hydrogenerator 16 providing the hydraulic drive power or braking power required in each case.

The forging hammer 1 can further comprise a position and / or speed sensor 23, with which the control unit 19 can determine a position and / or speed of the bear 8 or the piston 6, with corresponding position and / or speed data for control purposes of the hydraulic circuit, in particular the hydraulic pump 27 and / or the hydrogenerator 16 and / or the directional control valve 13, can be used, for example for controlling or setting a desired final speed or impact speed of the differential cylinder 2.

The forging hammer 1 shown in connection with the figures further comprises an energy store 24 in which secondary energy generated by the hydraulic generator 16, for example by converting hydraulic energy, in particular elastic energy, from the hydraulic circuit, for example in the form of electrical energy, can be stored. For charging and discharging control, the energy store 24 can be connected to the control unit 19. In particular, the energy store 24 and the associated one Control can be coordinated so that energy recovered from one or more preceding work cycles of the forging hammer 1 for operating the forging hammer 1, for example the hydraulic pump 27, is used or called up in subsequent work cycles.

The piston chamber 21 and the annular chamber 22 of the differential cylinder 2 are fluidically connected to the hydraulic tank 15 via suction valves 25 in order to compensate for any negative pressures that occur in the hydraulic system such that hydraulic fluid 30 is sucked in via the suction valves 25 from the hydraulic tank 15 in the event of a negative pressure and thus into the hydraulic system can be introduced.

In particular, the piston chamber 21 and the annular chamber 22 can each be fluidically connected to the hydraulic tank 15 or a hydraulic fluid source via a suction valve 25, so that in the event of a negative pressure hydraulic fluid is sucked into the piston chamber 21 or the annular chamber 22 by a suction effect caused by the negative pressure.

The suction valves 25 can, for example, be spring-loaded check valves or other similar valves which allow only unidirectional flow of hydraulic fluid in the direction from the hydraulic tank 15 to the piston chamber 21 or the annular chamber 22, but block in the opposite direction.

An exemplary operation of the forging hammer 1 based on the components described above is described below with reference to FIG FIG. 2 to FIG. 5 described, which show the forging hammer 1 in different operating states.

FIG. 2nd shows the forging hammer 1 in an operating state in which the hydraulic pump 27 and the directional control valve 13 are controlled by the control unit 19 such that the piston 6 of the differential cylinder 2 in the direction of the lower tool 4 is accelerated or moved for the purpose of machining a workpiece 26.

The directional valve 13 is designed in the present embodiment as a 4/2 way valve, and in the in FIG. 1 shown operating state switched so that a first connection A1, which is fluidly connected to the pressure side 12 of the hydraulic pump 11, is connected to a second connection A2, which is fluidly connected to the piston chamber 21. In this way, hydraulic fluid 30 can be pumped from the hydraulic tank 15 into the piston chamber 21 by appropriate control of the servo motor 10 by the hydraulic pump 11, so as to increase the stroke of the piston 6 and to transmit a hydraulic acceleration force to the piston 6.

Furthermore, in the FIG. 1 shown operating state, in which the piston 6 is accelerated or moved in the direction of the lower tool 4, a third port A3 of the directional control valve 13 fluidly connected to the annular space 22, and switched through to a fourth port A4 of the directional control valve 13, which is fluidically connected to the hydrogenerator 16, more precisely connected to the input side 17 of the hydraulic motor 28.

Since the forging hammer 1 in the present example is designed as an upper pressure forging hammer 1 with an upper differential cylinder 2, the weight forces of the moving mass also contribute to the acceleration of the bear 8 in the direction of the lower tool 4 in addition to the hydraulic forces generated by the hydraulic pump 27 and the hydrogenerator 16 , in particular from bear 8, piston rod 7, piston 6, upper tool 9, etc., at.

In the case of a vacuum forging hammer or vacuum forging bear, to which the present invention can also be applied, the weight forces when the bear accelerates in the direction of the workpiece to be machined counteract the hydraulic force, which can also be recorded in terms of control technology by the hydraulic system proposed here. With a combination of upper pressure and negative pressure, a forging hammer can be used Both the upper pressure and the lower pressure forging hammer can be controlled with the method proposed here and have a corresponding structure.

Coming back to the in FIG. 1 The state shown is further explained that in the operating state shown, the bear 8 is acted upon with hydraulic fluid 30 by the hydraulic pump 27, and the hydrogen generator 16, if necessary, draws hydraulic energy from the hydraulic system and acts as a hydraulic brake to the extent that the upper tool 9 when striking the workpiece 26 to be machined has a respectively desired impact speed or final speed, and accordingly a respectively desired or predetermined forming energy can be delivered to the workpiece.

To control the acceleration and setting of the speed of the bear 8, the control unit 19 can evaluate one or more position and / or speed sensors 23 and on the basis of the data obtained thereby, for example on the basis of the determined actual speed of the bear 8, or in accordance with the upper tool 9 or of the piston 6, control the hydraulic pump 28 and / or the hydrogenerator 16 such that the desired final speed is reached.

During the movement of the bear 8 or piston 6 in the direction of the workpiece 26 or lower tool 4, corresponding to the volume flow generated by the hydraulic pump 11, hydraulic fluid 30 flows into the piston space 21. At the same time, hydraulic fluid 30 located in the annular space 22 is displaced from the annular space 22, which is returned to the hydraulic tank 15 via the directional control valve 13 and the hydrogenerator 16.

Since the hydrogenerator 16 is switched on in the return line, elastic energy stored in the hydraulic system can, for example, be withdrawn from the hydraulic system and converted into electrical energy. The electrical energy can in turn be temporarily stored in the energy store and the forging hammer 1 in subsequent work cycles, or also be provided immediately. Elastic energy stored in the hydraulic system can be released, for example, by decompression of the hydraulic fluid 30.

Furthermore, by appropriate control of the hydrogenerator 16, i.e. of the servo generator 29, hydraulic energy is withdrawn from the hydraulic circuit by, for example, increasing the torque of the servo generator 29 so that kinetic energy of the hydraulic fluid flowing through the hydraulic motor 28 is converted into electrical energy. The latter leads to a braking effect overall, so that the moving mass, in particular piston 6, bear 8, etc., can be braked in a targeted manner.

This means that the hydrogenerator 16 in the hydraulic system proposed here can be operated as a hydrofluidic brake to generate a braking effect for the moving mass, in particular the bear 8. For example, the hydrofluidic braking effect can be used for the purpose of setting a respectively required final speed when moving in the direction of the first turning point U1 and / or for braking the moving mass when moving in the direction of the second turning point U2, e.g. be used in the region of the upper second turning point with appropriate control of the hydrogenerator 16.

With the solution proposed here, the hydraulic pump 27 and the hydrogenerator 16 can be operated essentially simultaneously at any time during the entire working cycle, the hydraulic pump 27 making it possible to generate a (positive) acceleration force and the hydrogenerator 16 making it possible to generate an opposite braking force. In particular, this enables a comparatively exact and precise control of the movement sequence, for example of the bear 9, essentially, ie for example apart from periods in which the directional valve 13 is reversed, to be achieved during the entire working cycle of the forging hammer 1.

Any, in the hydraulic system, i.e. Hydraulic system, underpressure occurring on the piston chamber side can be compensated for in the forging hammer 1 shown in particular by the fact that hydraulic fluid 30 can flow in via the suction valve 25, which is fluidically connected to the piston chamber 21 and the hydraulic tank 15.

Negative pressures in the part of the hydraulic system on the piston chamber side can occur, for example, if, during the acceleration of the bear 8, the volume flow of hydraulic fluid 30 generated by the hydraulic pump 27 remains behind the volume change caused by enlarging the piston chamber 21. The latter can occur, for example, if the change in volume of the piston chamber 21 caused by the accelerating effect of gravity is greater than the volume flow of hydraulic fluid 30 provided by the hydraulic pump 27.

For example, after a predetermined acceleration time or phase, i.e. at or after the end of the hydraulic filling time of the piston, the volume flow of the hydraulic pump can be reduced so that the piston reaches the respectively predetermined final speed.

In exemplary operations, the time required to move the bear 8 from a second reversal point U2 of the piston 6 or the bear 8 to the first reversal point U1, which is distant from the lower tool 4, can be approximately 200 ms (milliseconds).

With regard to the masses to be moved, which can be quite considerable with forging hammers, up to several tons and comparatively high top speeds, correspondingly high hydraulic capacities are required, which moreover have to be regulated and controlled in a comparatively short time and moreover with high accuracy.

In addition, comparatively high volume flows of hydraulic fluid and comparatively high flow speeds occur in forging hammers in the hydraulic circuit, which must be controlled accordingly to ensure safe and reliable operation.

In particular, these aforementioned tasks and challenges can be solved with the forming machine proposed and described herein, in particular the hydraulic system proposed here.

FIG. 3rd shows the forging hammer 1 in an operating state in which the bear 8 is in the first reversal point U1, ie in the present case the lower reversal point. By the bear 8, in particular the upper tool 9 striking the workpiece 26, the mass being moved in each case, including in particular the mass of the bear 8, the upper tool 9, the piston 6, the piston rod 7, is braked, the kinetic energy being converted into energy Workpiece 26 is introduced for its forming.

In particular, by means of the hydraulic system proposed here with a hydraulic pump 27 and hydrogen generator 16 which can be operated simultaneously during the working cycle, it is possible to set the final speed of the bear 8 comparatively precisely, so that advantageous forging results can be obtained.

Immediately after or in the area of the impact of the upper tool 9 on the workpiece 26, a more or less pronounced rebound may occur on the braked mass, depending in particular on the material of the workpiece, which causes acceleration in a direction away from the lower tool 4 . Impact and rebound can take place, for example, in a time range from 0.5 ms to 20 ms.

Due to the rebound, the piston 6 in particular is suddenly moved from the first reversal point U1 in the direction of the second reversal point U2. On the one hand, this creates a displacement effect in the piston chamber 21 for the hydraulic fluid located therein, and on the other hand, a negative pressure is created in the annular space 22 or in the resulting annular space 22 and, correspondingly, a suction effect.

In order to take into account the changed conditions in the area of the impact and / or the first reversal point in the hydraulic system, the directional control valve 13 is controlled accordingly by the control unit 19, in particular in such a way that the third connection A3 is fluidly connected to the first connection A1, and that the second Port A2 is connected to the fourth port A4 of the directional valve 13. As a result, the piston chamber 21 is fluidly connected to the hydrogen generator 16, and the annular chamber 22 is fluidly connected to the pressure side 12 of the hydraulic pump 11. A corresponding reversal of the directional control valve 23 can also take place before the first reversal point U1, for example at the time when the bear 9 has the desired final speed. For example, the directional control valve 23 can be switched over at a point in time at which the respectively desired final speed is reached, and any braking or braking operation of the piston 6 or bear 8 that may be required has been completed. The braking process can take place, for example, in the end region of the movement of the bear 8 in the direction of the forming region or in the direction of the workpiece 26. The end of the braking process can be before the point of impact of the bear 8 in the work area. In this respect, the directional control valve 23 can be switched over in time, in particular shortly before the point of impact, in particular in such a way that the required switching position of the directional control valve 23 is at least at the point of impact.

In general, the control of the directional control valve 23 can take place in such a way that control processes, in particular taking into account any system inertia or switching times, are initiated with a time delay such that the switching position of the directional control valve 23 required for a certain point in time is reliably reached at the respective point in time.

In the switching position of the directional valve 13, which in the operating state of FIG. 4th shown, hydraulic fluid 30 displaced from the piston chamber 21 can be discharged via the hydrogenerator 16 into the hydraulic tank 15 by the displacement effect. In particular, the one with the rebound in Hydraulic system generated and released by decompression of the hydraulic system elastic energy from the hydrogen generator 16 are converted into electrical energy, wherein the hydrogen generator 16 is controlled accordingly via the servo generator 29 so that it can be driven by the hydraulic motor 28 at least partially convert the elastic energy into electrical energy.

The electrical energy can be stored in the energy store 24 electrically connected to the servo generator 29 and e.g. for subsequent work cycles for electrically driving the hydraulic pump 27 and others be used.

Furthermore, hydraulic fluid 30 can be supplied to the annular space 22 through the fluidic connection of the hydraulic pump 27 and the annular space 22 in order to at least partially provide the hydraulic fluid required in the annular space 22 due to the movement of the piston in the direction of the second reversal point U2 or the annular space 22 in accordance with the movement of the To supply piston 6 at least partially with hydraulic fluid 30.

Due to the comparatively high accelerations occurring during the rebound, it can happen that the change in volume of the annular space 22 caused by the movement of the piston 6 in the direction of the second reversal point U2 is greater than the volume flow supplied by the hydraulic pump 27. In this situation, an underpressure or suction effect can occur on the annulus side, despite the active hydraulic pump 27, which can be compensated for by the suction valve 25 on the annulus side in accordance with the solution proposed here. The annulus 22 is connected fluidically to the hydraulic tank 15 through the annulus-side suction valve 25, so that hydraulic fluid 30 can flow into the annulus 22 from the hydraulic tank 15 due to the suction effect.

The suction valve or valves 25 can, as already mentioned, be designed as check valves and offer the possibility of vacuum peaks in the hydraulic system, without this requiring a full control of the hydraulic system by the control unit 19.

In particular, to compensate for negative pressure peaks, or generally negative pressures, it is not necessary to operate the hydraulic pump 27, for example in the region of the rebound, at a correspondingly high speed and correspondingly high delivery rate. Instead, after reversing the directional valve 13 according to the configuration FIG. 4th , in which the hydraulic pump 27 is fluidly connected to the annular space 22 and the hydrogenerator 16 is fluidly connected to the piston space 21, the hydraulic pump 27 is operated by the control unit 19, for example, at a minimum speed or minimum delivery rate which is required around the piston 6 after decay of the rebound to move to the second reversal point U2 at the desired speed. In this way, the control effort in particular can be reduced.

The movement of the piston 6 from the first U1 to the second reversal point U2 can e.g. in about 500 ms.

When reaching or in a period before reaching the second turning point U2, the control unit 19 can control the hydraulic circuit, in particular the directional control valve 13 and the hydraulic pump 27 and the hydrogenerator 16, in such a way that the piston 6 together with the moving mass connected to it is braked. The braking process can be performed in exemplary working cycles e.g. in a time span of approx. 100 ms.

To brake the piston 6 and the mass moved thereby in the area of the second turning point U2, the control unit 19 can control the hydrogenerator 16 in such a way that hydraulic energy is withdrawn from the hydraulic fluid flowing back from the piston chamber 21 by the hydrogenerator 16, so that the hydrogenerator 16 acts as a hydrofluidic brake works.

At the same time, if not already done, the hydraulic pump 27 can be controlled in such a way that its delivery quantity is or is reduced, for example in such a way that the hydraulic pump 27 is operated at the minimum speed.

When braking, with an upper pressure operated forging hammer according to the figures, the force of gravity acting on the moving mass additionally acts as a brake for the movement in the direction of the second reversal point U2.

For braking in the area of the second turning point U2, the hydraulic system is in any case controlled so that the bear 8 is completely braked in the second turning point U2, possibly using sensor-based position and / or speed data of the bear 8. Merely the completeness is noted that in the first turning point U1 the moving mass is braked as such by the forging process, but in the first turning point U1 effects such as rebound must be absorbed or managed by suitable control of the hydraulic system.

After braking in the second reversal point U2, the control unit 19 can control the hydraulic system in accordance with the previously described flowchart to carry out a further work cycle. The control unit 19 can control the directional control valve 13 in such a way that the hydraulic pump 27, as in FIG FIG. 2nd shown, is fluidly connected again to the piston chamber 21 and the hydrogenerator 16 is fluidly connected again to the annular space 22.

If, in a subsequent work cycle, for example, an impact speed different from a previous work cycle is required, the hydraulic pump 27 and the hydrogen generator 16 can be controlled accordingly when the moving mass is accelerated and, if necessary, when the moving mass is decelerated to set the given impact speed.

It should be noted here that a change or variation of the impact speed with the hydraulic system proposed here and the connection proposed here of the hydraulic pump 27, the directional control valve 13 and the hydrogenerator 16 and the control unit 19 connected therewith can be accomplished comparatively easily. In particular, the system proposed here can be used to react comparatively flexibly to changed boundary conditions by correspondingly changing the control, possibly with additional evaluation of pressure, position or speed sensors.

FIG. 5 shows a working diagram relating to operating and control variables of the forging hammer 1, a total of five curves being shown, a first speed curve D1 describing the time dependence or the time course of the speed of the hydraulic pump 11. A second speed curve D2 describes the time dependency or the time course of the speed of the hydrogenerator 16.

A first torque curve M1 describes the time dependence or the time profile of the torque of the hydraulic pump 11, and a second torque curve M2 shows the time dependency or the time profile of the torque of the hydrogenerator 16.

A movement curve B describes the time dependence or the time profile of the stroke of the piston 6 or bear 8. According to the movement curve B, the piston moves from the second reversal point U2 to the first reversal point U1, and then back to the first reversal point U1.

In the example of the movement sequence shown according to movement curve B, the piston 6 or bear 8, corresponding to the start of a work cycle, is at a start time t0 at t = 0 in the second reversal point U2. The bear 8 or piston 6 is accelerated from the second reversal point U2 in the direction of the first reversal point U1, the directional control valve 13 being controlled in such a way that the hydraulic pump 27 is fluidly connected to the piston chamber 21. In this operating state, the hydrogenerator 16 is fluidically connected to the annular space 22.

For acceleration, the pump torque of the hydraulic pump 27 and thus the power which can be transmitted to the hydraulic system is increased in accordance with a comparatively steep flank, in the curve shown here as an example FIG. 5 down to about 1100Nm.

As the speed of the bear 8 increases, the torque required to accelerate the bear 9 decreases, not least because the gravity of the moving mass also contributes to the acceleration. The bear 8 and the moving mass is accelerated to a first point in time t1, which is before a second point in time t2, in which the bear 8 reaches the first reversal point U1.

Along with the increasing speed of the bear 8 or piston 6, the speed of the hydraulic pump 27 increases from the minimum speed Dmin to the maximum speed Dmax corresponding to the change in volume of the piston chamber 21 caused by the movement of the piston 6. In the same period between t0 and t1, hydraulic fluid 30 becomes , with increasing volume flow, displaced from the annular space 21, the speed of rotation of the hydrogenerator 16, ie the speed of the hydraulic motor 28 of the hydrogenerator 16 increases.

In the period between the first point in time t1 and the point of impact, which essentially corresponds to the second point in time t2 assigned to the first reversal point U1 in the diagram, that is to say in the period between the end of the acceleration phase and the point of impact, the respective final speed can optionally be set.

To adjust the speed, the directional control valve 13 can be reversed so that the hydraulic pump 27 is connected to the annular space 22 and the hydrogenerator 16 to the piston space 21. Here, as exemplified in The diagram shows that the torque of the hydrogenerator 16 is increased in the period between t1 and t2, which means in particular that energy is withdrawn from the hydraulic fluid flowing into the piston chamber, which ultimately brakes the volume flow to the piston chamber 21, as a result of which the bear 9 has a braking effect can be generated. This means that the hydrogenerator 16 acts as a hydrofluidic brake in this period, in order to counteract any further acceleration of the bear 8 after the end speed has been reached.

The speed of the hydrogenerator 16 is approximately constant between t1 and t2 at the point in time mentioned (see curve D2). Before time t1, in the example the FIG. 5 in the time interval between t0 and t1, the speed of the hydrogen generator 16 can be set to the speed required for generator operation, in particular increased.

The torque of the hydrogenerator 16 (see curve M2) increases until the second time t2, which e.g. can mean that the hydrogenerator 16 actually draws hydraulic energy from the hydraulic system.

With regard to in FIG. 5 curves of torque and speed of the hydraulic motor 28 and hydrogen generator 16 shown by way of example should be noted that the actual course of the curves may vary depending on the respective hydraulic system. For example, the course of the speed and / or torque can be offset in time from the times t0 to t4, which can be caused, for example, by different mass inertias and / or fluid inertias of the hydraulic fluid and / or components of the hydraulic system. For example, the increase in the speed of the hydrogen generator 16 before the time t1 to the speed required or suitable for generator operation can also be done otherwise than by the method shown in FIG FIG. 5 shown course can be achieved. In other words, the speed and torque of the hydraulic motor and / or the hydrogenerator can vary depending on the respective forging hammer Design and dimensioning of the hydraulic system in particular FIG. 5 shown course deviate.

At the same time, in the period between t1 and t2, the hydraulic pump 27 is controlled in such a way that the speed drops to the minimum speed Dmin, the torque increasing when the final speed is reached.

It should be mentioned here that the speed and torque of the hydraulic pump 27 are set such that, from the second point in time t2, the piston can be moved from the first reversal point U1 towards the second reversal point U2 at a predetermined return speed, for example 2 m / s.

From the second point in time t2, the hydraulic pump 27 is corresponding to the in FIG. 5 shown example run according to the previously set minimum speed Mmin and the corresponding torque, and bear 8 or piston 6 are moved from the first reversal point U1 to the second reversal point U2. So that the hydrogenerator 16 does not act as a hydraulic brake for the return movement and acts as a brake on the hydraulic pump 27, the torque of the hydrogenerator 16 is reduced to zero after the second period. The speed of the hydrogenerator 16, ie the hydraulic motor 28, results in this period in particular from the volume flow of the hydraulic fluid 30 displaced from the piston chamber 21.

The return movement of the piston 6 is slowed down from a third point in time t3 in such a way that the piston 6 together with the associated moving mass is braked in the second reversal point U2 and the working cycle can be repeated.

For braking, the torque of the hydrogenerator 16 is increased so that it acts as a hydraulic brake for braking the mass moving in the direction of the second reversal point U2. Along with this, the torque of the hydraulic pump 27 is reduced, which also leads to a slowdown the return movement leads. These measures and the acting gravity completely brake the moving mass up to a fourth time t4, which defines the end of the working cycle.

The fourth point in time can be followed by a further working cycle which is carried out in accordance with the previously described working cycle, wherein after reversing the directional control valve 13, the hydraulic pump 27 is again connected to the piston chamber 21 and the hydrogenerator 16 is connected to the annular chamber 22 again.

Overall, it is shown that by means of the proposed hydraulic system, a comparatively precise control of the hydraulic motor 28 and hydrogen generator 16 is possible, such that the bear 8 can be controlled in accordance with a respectively predefined movement sequence and movement and speed curve, and at the same time the energy loss occurring in the hydraulic system Useful energy can be converted. Due to the control proposed here and the proposed construction of the hydraulic system of the forging hammer, comparatively precise and energy-efficient working cycles for the differential cylinder 2 and forging hammer 1 can be implemented.

In particular, due to the possibility of the simultaneous operation of hydraulic pump 27 and hydrogen generator 16, a comparatively precise and reliable setting of the movement sequence and the speed, in particular the final speed or impact speed, of the bear 9 can be achieved.

Relief and simplification of the control of the arrangement proposed here consisting of hydraulic pump, hydrogenerator and directional valve can be achieved, for example, by the suction valves 25, which automatically, so to speak, any negative pressure conditions and pressure peaks, for example hydraulic impacts on the piston, hydraulic pump, hydrogenerator and / or directional valve assembly, in the hydraulic System can compensate. The latter is not only beneficial on the control effort, but at the same time a comparatively low-wear operation can also be achieved.

Reference list

1

Forge hammer

2nd

Differential cylinder

3rd

Lower die

4th

Lower tool

5

Cylinder barrel

6

piston

7

Piston rod

8th

bear

9

Upper tool

10th

Servo motor

11

hydraulic pump

12th

Printed page

13

Directional control valve

14

Suction side

15

Hydraulic tank

16

Hydrogenerator

17th

Home page

18th

Exit side

19th

Control unit

20

Pressure sensor

21

Piston chamber

22

Annulus

23

Position or speed sensor

24th

Energy storage

25th

Suction valve

26

workpiece

27

servomotor hydraulic pump

28

Hydraulic motor

29

Servo generator

30th

Hydraulic fluid

U1

first turning point

U2

second turning point

A1 - A4

first to fourth connection

D1, D2

Speed curve

M1, M2

Torque curve

B

Movement curve

t0

Start time

t1 - t4

first to fourth time

Dmin

Minimum speed

Dmax

Maximum speed

Claims (17)

1. Forging hammer (1) for shaping workpieces (26), comprising a striking tool (8, 9) and a hydraulic linear drive (2, 13, 16, 19, 27) that is coupled to the striking tool (8, 9) and is designed to drive the striking tool (8, 9), said linear drive having a hydraulic circuit comprising a servomotor-driven hydro pump (27), a hydraulic cylinder (2), in particular a differential cylinder (2), which is fluidically connected downstream to the hydro pump (27) via a directional valve assembly (13), and a servomotor-driven hydro generator (16) which is fluidically connected downstream to the hydraulic cylinder (2) via the directional valve assembly (13), and further comprising a control unit (19) which is designed to at least control (19) the hydro pump (27), the hydro generator (16) and the directional valve assembly (13), wherein the hydro pump (27), using the directional valve assembly (13), is configured as a unidirectional servomotor-driven hydro pump (27) and is integrated into the hydraulic circuit, and wherein the servomotor-driven hydro generator (16), using the directional valve assembly (13), is configured as a unidirectional servomotor-driven hydro generator (16) and is integrated into the hydraulic circuit.
2. Forging hammer (1) according to claim 1, wherein the control unit (19) is configured such that the directional valve assembly (13) is actuated at least temporarily during a working movement of the hydraulic cylinder (2) such that the hydro pump (27) is fluidically connected to a first fluid chamber (21), in particular a piston chamber (21), and the hydro generator (16) is fluidically connected to a second fluid chamber, in particular an annular chamber (22), of the hydraulic cylinder (2), and such that the directional valve assembly (13) is actuated at least temporarily during a return movement of the hydraulic cylinder (2) such that the hydro pump (27) is fluidically connected to the second fluid chamber (22) and the hydro generator (16) is fluidically connected to the first fluid chamber (21) of the hydraulic cylinder (2), and/or
   wherein the control unit (19) is configured such that the hydro pump (27) is alternately connected to a or the first fluid chamber (21) and to the second fluid chamber (22) of the hydraulic cylinder (2) in sequentially successive, in particular immediately successive, portions of a working cycle of the hydraulic cylinder (2), wherein optionally the hydro generator (16) is correspondingly alternately connected to the second fluid chamber (22) and to the first fluid chamber (21).
3. Forging hammer (1) according to either claim 1 or claim 2, wherein the directional valve assembly (13) comprises a 4/2 way valve (13), or wherein the directional valve assembly comprises at least four individual hydraulic valves that are fluidically connected in a bridge circuit, wherein the bridge circuit is optionally designed as a polygonal circuit of four hydraulic valves having intermediate connection points, is also optionally implemented as a parallel circuit of in each case two hydraulic valves that are connected in series,
   and/or
   wherein the hydraulic circuit comprises a plurality of hydro pumps (27) that are fluidically connected in parallel and/or the hydraulic circuit comprises a plurality of hydro generators (16) that are fluidically connected in parallel.
4. Forging hammer (1) according to either claim 1 or claim 2, or to claim 3 if dependent on claim 2, wherein the hydraulic circuit comprises at least one feeder valve (25) which is fluidically connected on one side to a feeding source (15) and on the other side to at least one fluid chamber (21, 22) of the hydraulic cylinder (2), in particular to the piston chamber (21) and/or annular chamber (22), the fluidic connection of the suction valve (25) optionally being designed such that a negative pressure that arises in the at least one fluid chamber (21, 22) during operation of the hydraulic cylinder (2), in particular the differential cylinder (2), can be compensated for by feeding in hydraulic fluid by means of the feeder valve (25).
5. Forging hammer (1) according to any of claims 1 to 4, wherein the control unit (19) is configured to control the pump speed of the hydro pump (27) such that, during operation, said hydro pump is operated at least at a minimum speed (Dmin) that differs from zero, wherein the pump speed in a working region of a working cycle of the hydraulic cylinder (2) is preferably first increased from the minimum speed (Dmin) to a maximum speed (Dmax) and is subsequently decreased from the maximum speed (Dmax) to the minimum speed (Dmin), wherein the control unit (19) is optionally configured such that the hydro pump (27) is always operated at least at the minimum speed (Dmin) during a plurality of immediately successive working cycles, wherein
   the control unit (19) is also optionally configured such that the hydro pump (27) is first activated at the minimum speed (Dmin), and subsequently the pump speed in a working region of a working cycle of the hydraulic cylinder (2) is first increased from the minimum speed (Dmin) to a maximum speed (Dmax), and the pump speed is also optionally decreased from the maximum speed (Dmax) to the minimum speed (Dmin) in a subsequent working portion, in particular such that the minimum speed (Dmin) is achieved in a reversal point of the hydraulic cylinder (2), wherein the pump speed of the hydro pump (27) is also optionally increased correspondingly with a linear function of time, wherein the control unit (19) is also optionally configured such that, when a predetermined final speed of the striking tool (8, 9) has been reached, starting from when the maximum speed (Dmax) has been reached, the pump speed of the hydro pump (27) is reduced such that, under the influence of the hydraulic forces prevailing in the hydraulic circuit and, if applicable, the force of gravity acting on the striking tool (8, 9), the predetermined final speed is achieved in or shortly before or immediately before the reversal point, or shaping point, or in or shortly before or immediately before the reversal point of the shaping point, wherein, in order to set the final speed, the hydro generator (16) is optionally operated as a hydraulic brake in order to actively brake the hydraulic piston (2).
6. Forging hammer (1) according to any of claims 1 to 5, wherein the control unit (19) is designed and configured to control the hydro pump (27) such that a maximum feeding speed of the differential cylinder (2) is in the range of between 1.0 to 6 m/s, and/or wherein the control unit (19) is configured such that a starting point for starting a shaping or forging process depending on a final speed that is required in each case, depending on the height of the workpiece (26) to be shaped, which height is measured in the direction of movement of the hydraulic piston (2), and/or wherein the control unit is configured such that the distance covered by the striking tool (8, 9) during a forging cycle is minimal, and/or wherein the control unit (19) is configured such that striking energy of a previously driven stroke is used to calculate the starting position of the hydraulic piston (2) on the basis of subsequently required striking energy, wherein the starting position is optionally set depending on the particular height of the workpiece (26) to be shaped, and/or the control unit (19) is configured such that a position, in particular the starting position, of the hydraulic piston (2) at the beginning or at a defined point in time is determined during a shaping or forging cycle and is used as a calculation basis for determining a starting position of the hydraulic piston (2) and/or for operating parameters for controlling the movement of the hydraulic piston (2) for a chronologically subsequent shaping or forging process.
7. Forging hammer (1) according to any of claims 1 to 6, further comprising an energy storage means (24) which is connected to the hydro generator (16) for the purpose of feeding electrical energy generated by the hydro generator (16).
8. Method for controlling a working cycle of a forging hammer (1), wherein a hydraulic cylinder (2), in particular a differential cylinder (2), that is coupled to a striking tool (8, 9) is driven by the supply of hydraulic fluid (30) by means of a servomotor-driven hydro pump (27) of a hydraulic linear drive (2, 13, 16, 19, 27), which hydro pump is fluidically coupled via a hydraulic circuit and a directional valve assembly (13) that is fluidically connected upstream to the hydraulic cylinder (2), wherein hydraulic fluid (30) that flows out from the differential cylinder (2) is conveyed, via the directional valve assembly (13), to a servomotor-driven hydro generator (16) that is fluidically connected downstream into the hydraulic circuit of the directional valve assembly (13), wherein the hydro pump (27), using the directional valve assembly (13), is operated as a unidirectional servomotor-driven hydro pump (27) and wherein the servomotor-driven hydro generator (16), using the directional valve assembly (13), is operated as a unidirectional servomotor-driven hydro generator (16).
9. Method according to claim 8, wherein, at least temporarily during a working movement of the hydraulic cylinder (2) the directional valve assembly (13) is actuated such that the hydro pump (27) is fluidically connected to a first fluid chamber (21) of the hydraulic cylinder (2), in particular a piston chamber (21), and the hydro generator (16) is fluidically connected to a second fluid chamber (22) of the hydraulic cylinder (2), in particular an annular chamber (22), and such that, at least temporarily during a subsequent return movement of the hydraulic cylinder (2), the directional valve assembly (13) is actuated such that the hydro pump (27) is fluidically connected to the second fluid chamber (22), in particular the annular chamber (22), and the hydro generator (16) is fluidically connected to the first fluid chamber (21), in particular the piston chamber (21), of the hydraulic cylinder (2), and/or wherein, in sequentially successive, in particular immediately successive, portions of a working cycle of the hydraulic cylinder (2), the hydro pump (27) is alternately connected to a or the first fluid chamber (21) and second fluid chamber (22) of the hydraulic cylinder (2), wherein the hydro generator (16) is optionally correspondingly alternately connected to the second fluid chamber (22) and the first fluid chamber (21).
10. Method according to either claim 8 or claim 9, the hydro pump (27) is controlled by the control unit (19) such that, during operation, the hydro pump (27) is operated at least at a minimum speed (Dmin) that differs from zero, wherein the pump speed in a working portion of a working cycle of the differential cylinder (2) is preferably first increased from the minimum speed (Dmin) to a maximum speed (Dmax) and then decreased from the maximum speed (Dmax) to the minimum speed (Dmin), and wherein, preferably during a return portion of the working cycle, the pump speed is set or adjusted to the minimum speed (Dmin).
11. Method according to any of claims 8 to 10, wherein, in order to accelerate a piston (6) of the hydraulic cylinder (2) in the direction of a first reversal point (U1) that is associated with the shaping region (4) of the forging hammer (1), the pump speed of the hydro pump (27) is increased from a or the minimum speed (Dmin), in particular in a linear dependence on time, to a or the maximum speed (Dmax) such that the maximum speed (Dmax) is achieved before reaching a first reversal point (U1) that is associated with the shaping region (4) of the hydraulic cylinder (2), wherein the pump speed of the hydro pump (27) is preferably reduced after the maximum speed (Dmax) has been reached, in particular in a linear relationship with time, such that the minimum speed (Dmin) is achieved when the first reversal point (U1) has been reached, wherein the hydro pump (27) is always operated at least at the minimum speed (Dmin) during a plurality of immediately successive working cycles, wherein the hydro pump (27) is also optionally activated first at the minimum speed (Dmin), and then the pump speed in a working region of a working cycle of the hydraulic cylinder (2) is increased from the minimum speed (Dmin) to a maximum speed (Dmax), and also optionally, in a subsequent working portion, the pump speed is decreased from the maximum speed (Dmax) to the minimum speed (Dmin), in particular such that the minimum speed (Dmin) is achieved in a reversal point of the hydraulic cylinder (2), wherein, when a predetermined final speed of the striking tool (8, 9) has been reached, starting from when the maximum speed (Dmax) has been achieved, the pump speed of the hydro pump (27) is also optionally reduced such that the predetermined final speed is achieved in or shortly before or immediately before the reversal point, or shaping point, or in or shortly before or immediately before the reversal point of the shaping point under the influence of the hydraulic forces prevailing in the hydraulic circuit, and, if applicable, the force of gravity acting on the striking tool (8, 9), wherein, in order to set the final speed, the hydro generator (16) is optionally operated as a hydraulic brake in order to actively brake the hydraulic piston (2).
12. Method according to any of claims 8 to 11, wherein, when a or the first reversal point (U1) of the forging hammer (1) that is associated with a shaping region (4) has been reached, or when a predetermined speed of the rams (9) has been reached, the directional valve assembly (13) is actuated such that a pressure outlet (12) of the hydro pump (27) is fluidically connected to a or, if dependent on claim 9, to the second fluid chamber (22) of the hydraulic cylinder (2), in particular an annular chamber (22) of the differential cylinder (2), and a pressure inlet (17) of the hydro generator (16) is fluidically connected to a or, if dependent on claim 9, to the first fluid chamber (21) of the hydraulic cylinder (2), in particular the piston chamber (21) of the differential cylinder (2).
13. Method according to claim 12 if dependent on claim 9 or a claim referring back to claim 9, wherein a negative pressure that is generated by rebound in the first reversal point (U1) is compensated for in the second fluid chamber (22), in particular the annular chamber (22), by means of a feeder valve (25) that is fluidically connected on one side to the second fluid chamber (22) and on the other side to a hydraulic tank (15), and, preferably, elastic energy generated by the rebound in the hydraulic circuit is converted into electrical energy by means of decompression by the hydro generator (16), and is preferably stored in an intermediate storage means (24).
14. Method according to either claim 8 or claim 13, wherein, when a second reversal point (U2) of the hydraulic cylinder (2) that is remote from the shaping region (4) of the forging hammer (1) has been reached, the directional valve assembly (13) is actuated such that a pressure outlet (12) of the hydro pump (2) is fluidically connected to a or, if dependent on claim 9 or a claim referring back to claim 9, to the first fluid chamber (21) of the hydraulic cylinder (2), in particular the piston chamber (21) of the differential cylinder (2), and a pressure inlet (17) of the hydro generator (16) is fluidically connected to a or, if dependent on claim 9 or a claim referring back to claim 9, to the second fluid chamber (22) of the hydraulic cylinder (2), in particular the annular chamber (22) of the differential cylinder (2).
15. Method according to any of claims 8 to 14, wherein a starting point for starting a shaping or forging process depending on a required final speed, depending on the height of the workpiece (26) to be shaped, which height is measured in the direction of movement of the hydraulic piston (2), and/or wherein the distance covered by the striking tool (8, 9) during a forging cycle is minimal.
16. Method for controlling a forging hammer (1) according to any of claims 1 to 7, wherein a plurality of successive working cycles is/are controlled according to a method according to any of claims 8 to 15, wherein the hydro pump (27) is operated at least over the plurality of working cycles at a minimum speed that differs from zero.
17. Method according to claim 16, wherein secondary energy generated in a working cycle by the hydro generator (16) is supplied in a subsequent working cycle of the forging hammer (1) and/or wherein striking energy of a previously driven stroke is used to calculate the starting position of the hydraulic piston (2) on the basis of subsequently required striking energy, and/or wherein a position, in particular a starting position, of the hydraulic piston (2) is determined at the beginning or at a defined point in time during a shaping or forging cycle and is used as a calculation basis for determining a starting position of the hydraulic piston (2) and/or for operating parameters for controlling the movement of the hydraulic piston (2) for a chronologically subsequent shaping or forging process.

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